6’x12’-6000# Utility Trailer

A product from MechanicalElements.com

Construction Instructions

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 1
 6’ x 12’ – 6000# Utility Trailer Construction Instructions

Thank you for purchasing the plans for one of the best trailer designs around. This trailer is designed
specifically as a heavy-duty, utility trailer with a low profile bed and options for versatility. The design
incorporates strength in the main frame rather than requiring sides – even short sides – to give adequate
strength. This trailer is designed tough for long, faithful service – so it may be a little heavier than some.
This approach allows the trailer to be used in numerous ways for maximum utility and versatility.

Your success with the trailer is dependent on the care given in construction – including materials used,
construction techniques and assembly methods. If you build it well, it will perform well. Load capacity is
dependent on the axle, tires, options and proper load application. The specified capacity does not include
capabilities of purchased parts like the hitch, chain, axle, tires, etc.. Do not exceed manufacturer limits.

As a reminder, these plans are for individual use only. Any use of these plans for resale or
for producing products for sale is prohibited. Licensing for production and/or resale is
available on request. Intellectual property rights for all materials are reserved. We thank you
again for honoring these terms.

We truly hope you will enjoy your trailer, and to help ensure that, we have included a section of Towing
Tips at the end. Please use caution and proper safety equipment while building and using the trailer.

Components Required:

− Axle Assembly:
Axle with spring centers at 72”. Several variations are available. The axle you choose
should fit your particular application and the vehicle you will be towing it with. The
following items must be considered when choosing an axle:
• Axle Capacity – This trailer design will accommodate a load capacity of up to 6000 lbs.
Choose an axle applicable with this design requirement. This will determine how much
weight your trailer can carry.
• Straight or Drop axle – this will determine, in part, the bed height. A drop axle will lower
the trailer 4” from the straight axle. If you are pulling it with a truck or other high
clearance vehicle, the straight axle will probably match better. If you will be pulling with a
car or minivan, the drop axle may be a better choice. Also consider loading the trailer – if
ramps are used to roll things on and off, the drop axle and lower bed may be better.
• Underslung or Overslung Spring Mounts – this will also effect trailer height – overslung is
higher. We recommend underslung springs for better towing stability.
• Spring Type and Length – Typical trailer leaf springs are available in “Slipper” and “Eye”
styles. We recommend the Eye Style because they make less noise and move some
with a load. It can be argued that they help stability with a single axle arrangement.
Springs come in various sizes or lengths (distance from eye to eye). We recommend
longer springs for a softer ride. The 27” eye to eye spring length is shown. This trailer is
not designed for coil or pneumatic springs.
• With or Without Brakes – this will effect your stopping distance. If you carry heavy loads,
particularly with a lighter vehicle, we recommend using brakes. Next choose Hydraulic or
Electric brakes. Electric is more common, and easier to adapt to other vehicles.
Research this topic if you need more info. Some states don’t allow surge hydraulic.
Axles can be purchased from Rigid Hitch, Northern, or many other places.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 2
 The axle shown in these instructions is Rigid Hitch # M-D6072-E – 6000#, 4” Drop axle, 27”
springs centered and underslung at 72” with electric brakes. This comes with all
mounting hardware required. Similar axle assemblies can be purchased from other
sources, including local vendors. Check area listings in the phone directory.
− Wheels and Tires – these must match the axle bolt pattern. Specific trailer wheels and tires are
usually available with the axles, but another option is automotive. Most axles match an auto
bolt pattern (like a Ford 8-bolt) so common rims and tires can be used. For a great look, nice
wheels can be purchased from a scrap yard and standard tires mounted. Be sure the load
rating of the tires matches the load you expect. 235-85 R16 Load Rating E is typical. Also, if
wheels and tires for the trailer match the tow vehicle, an added spare may not be necessary.
− Trailer Fenders – we recommend heavy-duty fenders like the Rigid Hitch #8433 (though this
particular one may be a little small for big wheels and tires). Fenders come in different sizes,
configurations and materials. Choose plastic or composite for harsh weather conditions.
(Though you’ll have to find a different way to mount them.) The fenders must accommodate
the tire size and width. Check to see if your state requires fenders.
− Trailer Ball Coupler – must fit the ball size you use. We recommend a 2-5/16” ball (rated for
6000 lbs or more) and class IV – V receiver for a 6000 lb trailer. To mount on this trailer, the
coupler must accept a 3” wide rectangular tube. Rigid Hitch part # 80131 is pictured in these
instructions. Part # HB-28387 for a 2” ball, Part # HB-28462 for a 2-5/16” ball will also work.
− Safety Chains – are required in most states for trailers over a certain size or weight. Generally,
we recommend safety chains. Rigid Hitch part # 61 or 61-1 will be adequate.
− Lights, Wiring and Electric Connector – these items will depend on taste, choice of brakes, and
connector type. For lights, the Rigid Hitch parts # 3504 (left) and #3554(right) are water-
resistant and will nest in the rear channel of the trailer. Side marker lights (if needed,
depending on state laws and your preference), wiring and connectors, must also be selected.
We suggest a liberal wire size and length. It can help avoid future problems. Wiring
connectors that attach directly into your vehicles wiring are available for many vehicles.
Check local and internet sources.
− Optional Equipment:
• Tongue Jack and/or Swivel Wheel – to help in loading the trailer and moving it when not
attached to the vehicle. Rigid Hitch # 87743 will fit most applications with this trailer. It
will jack up the tongue, roll around, and snap up along side the tongue tube when the
trailer is in tow. The XP-10 is similar, and comes in either bolt-on or weld-on versions.
• Hitch handle – to lift tongue up to the hitch – not of much use with a heavy trailer or load.
• Toolbox – pictured in some views of this trailer. Many varieties exist from vendors like
Rubbermaid, and can be found at stores like K-Mart or Wal-Mart.
• Trailer Sides – pictured in some views of this trailer – may be temporary or permanent.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 3
Materials:
− Steel
• 5” x 2” x 1/8” (or 3/16”) wall, Rectangular Tube
– 2 @ 144” – main side rails.
• 4” x 5.4 lb. C-Channel
– 2 @ 73.5” –Bed back bumper channel & Bed front channel.
• 3” x 2” x 3/16” Angle – Option: for heavy or rough use, use 3” x 2” x 1/4” Angle
– 11 @ 69.5” – cross members.
– 2 @ 48” – axle spring mount angles.
– 2 @ 18” – rear angle braces – Option: use 2” x 1 1/2” x 3/16” Angle.
– 1 @ 30” – bed support angle – Option: use 2” x 1 1/2” x 3/16” Angle..
• 3” x 2” x 1/8” wall, Rectangular Tube
– 2 @ 70.5” – tongue angle braces.
• 3” x 3” x 1/4” Square Tube
– 1 @ 193” – tongue tube.
• 3” x 1/4” Flat Stock
– 1 @ 96” – tongue stiffener beam.
– 1 @ 18” and Several @ short lengths – tongue stiffener gussets.
– 4 @ 11” – Fender mounting brackets – Option: use 2” x 1/4” Flat Stock.
– Optional: Several @ 3” – spring mount lift shims (stack for correct height).
• 6” x 3/16” Flat Stock
– 4 @ 6” x 6” x 45° – frame gussets.
– 1 @ 10” w/angled sides (see drawing) – tongue gusset.
• 1” x 1/4” Flat Stock or 1” x 3/16” Flat Stock
– 4 @ 7” – optional tail light protectors – not needed with optional hinged tailgate.
– 2 @ 57” & 2 @ 31” – optional side mounted tie-down rails.
– 12 @ 1” – center supports for optional side mounted tie-down rails.
− Standard Bed option (double layer) as show on drawings:
• 4’ x 8’ x 1/2” Plywood Decking – 5 sheets – consider grade and treatment.
• Construction adhesive (like liquid nails)
− Optional Bed option (single layer):
• 4’ x 8’ x 3/4” or 4’ x 8’ x 1” Plywood Decking – 3 sheets – consider grade and treatment.
− Bed Option with integrated Unistrut for tie-down:
• 4’ x 8’ x 3/4” Plywood Decking – 3 sheets – consider grade and treatment.
• 12’ Unistrut Channel – 2 @ 144”
• 7/8” x 4” (3.5”) Spacers – must be true 7/8” thick to make deck flush with top of the
Unistrut. 1” thick will work but will make the plywood tight in the channels. Other
combinations like 7/8” plywood with 3/4" spacers will also work well.
– 2 @ 144”
– 11 @ 66.5” or width between unistrut channels – can vary with need.
• Construction adhesive (like liquid nails) – optional.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 4
 − Plank Bed option:
• Use appropriate 12’ 2x6 or 2x8 planks as desired – consider grade and treatment.
• This option will require more bolts and a different offset from the top surface of the frame
for setting the cross members. Be sure to make that adjustment in construction.
− 1/2" – 20 x 4” Grade 8 Bolts with locknuts and washers – 4 – for securing hitch coupler. Or weld
on coupler instead.
− 1/2" – 20 x 3” Grade 8 Bolts with locknuts and washers – 6 – for securing axle assemblies.
− 3/8" – 18 x 1.75” Carriage Bolts with locknuts and washers – 2.5” length for unistrut and plank
deck options – select appropriate number for chosen bed option – for securing decking to
frame cross members.
− Wheels, Tires and Lug nuts – many sizes and options available - 15”, 16” or 16.5” wheels - a
variety of tire sizes - 235-85 R16 (Load Range E) shown. Match tires to the load conditions.
− Sides Option: This will depend on your preferences – side height, top or no top, gate or door
configuration, permanent or removable, etc.. See drawings for more information.

** Due to the vast number of different requirements for sides, the plans show several options,
but materials required to build the sides are not included in this list. However, sides shown in
drawings are made from 2.5” x 1.5” x 1/8” Rectangular Steel Tube and 2.5” x 2” x 3/16”
Angle for the framing. 5/8" plywood is used inside.
− Paint and/or other finishing supplies (depending on finish desired)
− Pull-out Ramp Option (instead of hinged tailgate), (stores under trailer):
• 3/4” x 3/4” x 1/8” Angle – 2 @ 120” – under trailer ramp storage support angles.
• 2 1/2” x 1/4” Flat Stock
– 2 @ 96” – ramp side stiffener.
– 2 @ 5.25” – ramp catch plate ends.
• 4” x 1/8” Flat Stock
– 1 @ 24” – ramp catch plate.
• 2x4 or 2x6 x 8’ boards – 3 – for wood ramp core.
• 4 x 8 x 1/2” Plywood – 1 sheet – for wood ramp core.
• 1/2" x 4” steel rod or (bolts with the heads cut off) – 2 – for ramp catch plate.
• 2 short 2x2 or 1x2 pieces for handles.
• 48 #8 x 2” wood screws.
− Hinged Tailgate Option (instead of ramp):
• 2 1/2” x 1 1/2” x 3/16” Angle
– 6 @ 58” (or length of ramp) – linear cross members (vertical when gate is up).
Note: Gate length can change as required. Make length match accordingly.
– 2 @ 73.5” – end pieces, width of tailgate.
• 3/8” or 1/4" Flat Stock – Hinge Tabs
– 8 pieces, see drawing sheet 23 for more information.
• 72” x 60” Expanded Metal or Plywood – for gate and ramp surface
Note: Gate length can change as required. Make dimensions for these materials match
accordingly.
• 5/8” diameter @ 75” length Steel Rod – for Hinge

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 5
Tools Required:
− Saw, to cut steel (circular saw may be used with a metal cutting abrasive blade).
− Saw, to cut plywood (and wood spacers if applicable).
− Welder capable of welding steel at 1/4” thick.
− Hand grinder – for grinding welds and fitting metal pieces.
− Adequate Drill and drill bits for 1/4", 3/8”, 13/32”, 1/2” and 9/16” or 5/8” and 21/32” for hinged
tailgate/ramp option.
− C-clamps (many, varying sizes).
− Straight edge (min 48”), Square and Tape measure.
− Wrenches, pliers, screwdrivers, Hammer, files and other common hand tools.

Component Suppliers:
− Rigid Hitch Inc. 3301 W Burnsville Pkwy.
Burnsville, MN 55337-4290
Phone: 800-624-7630 or (952) 895-5001
We like Rigid Hitch (even though they don’t have a web site) because they carry higher quality
components. They might be a little more expensive and they’ll probably refer you to a dealer.

− Northern Tool & Equipment Phone: 800-221-0516

http://www.northerntool.com/

− Search the Internet there are lots of places that sell trailer parts and accessories on line.

− Check Local Sources. Most cities and towns have a local source for trailer parts and
accessories. Check local listings. This is a great way to see
things prior to purchase.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 6
 Utility Trailer Construction Instructions:

1. Locate and Print the trailer drawing sheets.

– If you ordered complete printed plans, the drawing sheets are included in the package.
– If you received plans electronically, the same drawings are provided in PDF format:
6x12-60utrailer-drawings.pdf
Print the drawings at the desired size (the Acrobat Reader gives options for print size or to shrink
large pages). Contact a local Kinko’s or similar print shop if you want a larger size and need
assistance printing it. (Max size is C, 22”x17”)

2. Look through these instructions and the drawings to determine which options you wish to include
on your trailer, then get the appropriate components and materials.

3. Layout the trailer outer 4 members of the frame. Layout the 4 perimeter sections (2 c-channel
ends and 2 rectangular tube sides) shown on Drawing Pages 3 & 4 for the main trailer frame. It
may be easiest to lay this out right side up since the “bottom” is all at one level. Use clamps and
straps to assure the parts will not move. It is often a good idea to clamp a few diagonals across the
frame to hold position. It is also good to check that the measurement from opposite corners is
equal – this will validate squareness – assuming the cut lengths are equal.

4. Tack weld the 4 corners then check squareness and flatness again. Make any adjustments
necessary. It is critical at this point that squareness is established as a sloppy start will yield a
sloppy finish, and this will effect how well the trailer tows.

5. Lay in the cross members. This is usually best done with the trailer frame upside down so the
angle iron has a flat place to set. Depending on the deck you will be using, shims (such as boards,
plywood or the unistrut for that option) may be used to “lift” the cross members to the correct
position. With spacers, the cross members will all line-up vertically and will all lay flat to the bed.

6x12-35 Trailer frame shown. Others similar - see drawings.

6. Tack weld the cross members in place. Keep checking squareness as you go because welds tend
to “pull” as they cool and you need to keep the frame square.

7. Layout and tack in the angle braces and gussets shown on Drawing Pages 4 & 5. Again, keep
checking squareness as you go.

8. Tack weld in the bed support angles shown on Drawing Page 5. Use the same spacers used with
setting the cross members to assure a flat bed. (Note: These pieces in the back are only to
support the deck and can be lighter – especially the 3 short pieces on the back channel. This will
make the trailer lighter, but only a little so if you have some stock lying around, this can be a good
idea. If not, don’t buy something special, the heavy stuff (as shown) will work great.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 7
9. Lay in the tongue tube. The tongue tube is set in place on the cross members or on the front and
back channel members depending on the bed option chosen. In the basic design (shown in the
drawings), the tongue tube rests on every cross member including the front and back channels.
Shims or notching may be required if variations are made from the standard design. See Drawing
Pages 4 & 6. The tongue must be square with the trailer frame. Tack this in place.

Option Note: The trailer tongue can be extended up to an additional 6 inches if desired. If done,
make sure to note the change in the bill of materials.

10. Lay in the tongue stiffener and gussets. The tongue stiffener can be bent and welded in place
over a center gusset to assure a perfect fit. Additional short gussets pieces can then be welded in
place between the tongue stiffener and the tongue tube as shown. This part will stiffen the tongue
to better support a front loaded trailer.

11. Add the tongue support braces. As shown on Drawing Page 7 the two tongue support braces are
added next. Each brace must be angle cut -- at one end to weld against the tongue tube, and at
the other to weld against the lowest 1” of the frame side beam. The tops of the support braces
should be at the same height as the tongue tube for best look and fit of the gusset plate to be
welded on later. These will also support the front toolbox or front storage area if that option is used.
Tack these braces in place.

For aesthetics, the ends outside ends may be angled and/or capped. Capping the ends will also
keep moisture out of the tube and decrease corrosion.

Bottom of completed 6x12-60 trailer.

12. Double check Squareness. At this point, all the structural members of the main trailer should be
tacked in place. If it is square and flat to your liking you are ready to weld it all together. If there
are tweaks to be made, do it now.

13. Completely weld the trailer frame together. Start in the corners, and stitch in a few areas. Do not
complete any one full weld until you have added several tacks to all the joints – especially the angle
braces and gussets. Check squareness again. Then complete the welding. By doing a little at a
time as you go around, the likelihood of creating a “pull” out of square is greatly reduced. The extra
effort will be well worth it.

14. Optional: Under trailer ramp storage. If desired, layout, tack, then weld on the under trailer ramp
storage angles. These must be straight and evenly spaced. Note the orientation shown on
Drawing Page 8.

15. Construct the Axle Spring Mounts. The left side axle spring mount is shown on Drawing Page 9.
You will need a right and a left. Care should be taken to make sure the holes line up as shown.
The axle spring anchors shown on the drawing should come with the axle and spring hardware.
We recommend that the spring mounts and springs be assembled together for tack welding to
assure proper alignment. Disassemble to complete the weld.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 8
 Depending on your chosen axle and springs, shims up to 1” thick may be required between the
spring anchors and the spring mount angles as shown on the drawing. Prior to mounting, be sure
the axle and springs allow enough space between the center member (tongue tube) and the axle.
Some springs are not arched as much so they won’t lift the trailer as high. Use shims as needed
for the spring mounts, or notch the tongue tube to allow for axle motion of 3 – 4 inches.

These spring mounts will be used to attach the axle to the trailer frame. The axle spring mounts
can then be moved fore or aft to better balance the trailer load. In this way the trailer can be
balanced to tow stable regardless of the load distribution on the bed. If the movable axle option is
not desired, the line of holes in the angle can be omitted, then the axle mounts can be welded to
the trailer frame.

16. Build the Axle. Assemble the axle components including the axle spring mounts built in the previous
step as shown in on the Drawing Page 10 and in the picture below. The tires and wheels must also
be assembled. (Note: because the straight axles are typically slightly narrower, if you are using
wide tires with a straight axle, you may need to get different rims (automotive rear drive) or shims to
move the wheels away from the axle spring mounts.)

Straight, Underslung Axle Assembly Shown. Others Similar.

17. Assemble the fenders to the axle spring mounts. With the tires and wheels on the axle, measure
for placement of the fenders. Clamp the fenders and mounting brackets to the axle spring mounts
as shown on Drawing Page 10. Make sure to allow a few inches of suspension travel – 3” to 4” is
adequate. We recommend you set-up and clamp both fenders and mounting brackets prior to
welding so they can be set to match. Tack them in place then disassemble items (like tires)
necessary to gain access for a full weld. (Note: if you think you will need to remove the fenders,
bolt them instead. It won’t be as strong or sturdy, but it will make removal much easier. For
fenders of other materials, like plastic, bolting will be required. Be sure to use washers near the
plastic for strength. Also, if you are concerned about splashing from the tires to your load, you can
fill the space between the fender and the axle spring mounts with sheetmetal or wood.)

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 9
18. Mount the axle assembly to the trailer frame. Hopefully you have a good way of managing heavy
objects, as the axle and the trailer frame must be assembled as shown on the Drawing Pages 11 &
12. (If you need a crane, you can check out our crane at www.MechanicalElements.com.) Measure
carefully from the center of the tongue tube (where the hitch will go) diagonally to the center of the
front spring bolts. This dimension must be the same for both sides. The dimension shown on the
drawing is a recommended position that will be good for most applications; however, one of the
great features of this trailer is the ability to move the axle as required for the load. When the axle
assembly is in the right place, secure it to the frame with clamps.

19. Drill the first axle mounting holes. With the axle assembly secured in the proper position, drill
through the 2 holes (2 each side of trailer) indicated on the Drawing Page 12 already in the axle
spring mounts, through the main side rails of the frame. These holes will be the base to measure
for the rest.

20. Drill the remaining axle mounting holes. After drilling the first holes, remove the axle assembly
and re-drill the 2 holes slightly larger – depending on the accuracy used in drilling the first set and
the holes in the axle spring mounts, you may wish to drill the holes at 9/16” (recommended) or 5/8”.
(This helps the bolts go in later when the axle is moved.) Measure and drill the remaining 5 axle
mounting holes in the c-channels of the trailer frame. This step is not necessary if you don’t ever
wish to change the axle position. Some disassembly may be required.

The movable axle option is beneficial for carrying widely varying loads, and for trailers that can
adapt to specific load requirements. Adjust the axle position so that the tongue carries-12% - 20%
of the load. (The shown dimension is ~12% for an evenly loaded trailer.) Additionally, each 3” the
axle is moved forward reduces the tongue load by ~1.5% to 2%. Be sure not to exceed
manufactures load ratings for the hitch, ball or receiver.

21. Position and mount the axle assembly. Reposition the axle assembly at the start location as
shown on the Drawing Page 11 (or other position if desired) then secure with bolts and locknuts.
You should be able to use 3 bolts on each side in most every axle position. The possible axle
positions are now in 3 inch increments forward and back. We strongly recommend using the nylon
insert lock nuts on all fasteners of a critical nature. Vibrations from the road have loosened too
many bolts to take a chance.

22. Attach the ball coupler. This is most easily done by clamping the coupler in place, then drilling the
tongue tube through the holes in the coupler. Once the holes are drilled, insert the mounting bolts
and tighten. Again, use locknuts.

23. Optional: Mount a Tongue Jack and/or Swivel Wheel. If you have chosen to use a tongue jack or
swivel wheel, mount it to the tongue tube. Most of these devises have bolts or plates that wrap
around the tube. Make sure yours can fit the tube. Drilling should not be required.

24. Wire the lights and brakes (if used). Check the laws of your state to determine requirements to be
met for lighting and brakes. Get appropriate lights (running lights if necessary) then wire the lights,
connectors and brakes (if used). Follow the manufacturer instructions. The picture below shows
the mounting of the taillight from Rigid Hitch indicated above.

25. Wire the electrical connector at the hitch. Choose a connector for your options (electric brakes,
etc.) and to match the tow vehicle. Purchase the connector and wire per manufacturer instructions.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 10
 We recommend protection on the wires to the connector like a sleeve to avoid damage with use.
Secure the sleeve and wires at the trailer tongue. An added welded bracket can be very useful.

26. Optional: Install the tail light protectors as shown on Drawing Page 13. Install the lights to assure
proper placement, then remove for welding. Be sure to allow space for installation and service of
the lights. If the hinged tailgate/ramp option is used, tail light protectors are not needed.

27. Optional: Install Tie-down bars around edges of frame. Bars in front and behind the wheels can
be added to the trailer frame for tie-down attachment (shown above and on Drawing Page 24).
These offer nice options for tie-down attachment – even with sides, these come in handy.

28. Optional: Install Tie-down hooks or D-rings. If bars like those in the step above are not desired,
tie-down hooks or D-rings can be installed around the trailer at strategic locations – both on the bed
and/or on the frame – for securing a load. Many choices are available including recessed rings that
can be mounted in the bed.

29. Build the trailer deck. The trailer deck shown on Drawing Page 14 is 1” thick, built of a double layer
of plywood (2 layers, 1/2" thick). By assembling the deck this way, all the seams will overlap
making the deck as strong and rigid as possible. It also minimizes the scrap plywood left over. For
some people this may be over-kill, so there are lots of options here.

Option: - By design, the 1” thick deck is flush with the side rails, so using a single layer of 1” thick
plywood is the first option. (Use only the pattern for the top layer.)

Option: - For weight reduction, use 3/4" plywood (with only patterns for the top layer shown in the
drawing). This will leave a 1/4" step up from the deck to the side rails. This may be desirable so
things won’t roll off as easily (while loading). It also makes an edge to brace against for tie-down.

Option: - If only a single layer of 3/4" plywood is desired, and the deck is to be flush with the top of
the rails, the cross members and tongue can be installed 1/4" higher than shown. In addition, the
tongue must move forward 1” to fit inside the back channel, and the front channel will need a notch.

Option: - If you prefer “2 by” decking instead of plywood, install the cross members 1/2" lower for 1-
1/2” decking. Lay the planks in lengthwise (long-wise). Add 1/2" steel spacers on the tongue tube.

Option: - Again, if you prefer “2 by” decking instead of plywood, another option is to use 2.5” x 2” x
1/4” thick angle iron instead of the specified 3” x 2” x 3/16” Angle. The shorter thicker angle will
allow the added 1/2" space for the plank deck without changing the construction and placement of
the tongue tube and bottom of the cross members. Again, lay the planks in lengthwise (long-wise).

Option: - For those who like lots of tie down options, embed unistrut (or something similar) into the
bed and put the decking (plywood) around it. That is shown in the pictures of our 5x10 utility trailer
on our web site, and the bed is illustrated (shown up side down) in the picture below.

Possible deck configuration using Unistrut (6x12-35 Bed Shown, Others similar.)
(View from the bottom showing required wood spacers, 1 for each cross member.)

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 11
 Unistrut is a trademark channel system of fastening that allows tie-down placement anywhere along
it. Spacers under the plywood lift the deck to flush with the Unistrut top. Assemble plywood and
spacer strips to resemble the groups shown. These may be glued together for strength and squeak
resistance. Be sure to overlap the pieces so seams are not at the same location. Place the unistrut
next to the side beams, or move them inboard slightly as illustrated. Note that Unistrut is 1-5/8” so
the spacers and plywood stack will need to be a similar thickness, and the cross members and
tongue will have to be “lowered” appropriately in the design to accommodate the option.

30. Assemble the deck to the frame. Once the deck is in place on the frame, drill through the cross
members from underneath and through the wood with a 3/8” drill as needed for each cross member
– 3 or 4 places evenly spaced in plywood decking will be sufficient. Use 3/8” carriage bolts to
secure the decking to the cross members. Tighten the bolts until the head of the carriage bolt is
just sinking into the wood as shown in the picture.

Please note: If a different bed option is chosen, the specified bolt length may need to change. If
Plank is used, an appropriate number of bolts (probably not in every cross member) will need to be
used. These variations will effect the bill of materials listed at the start of these instructions.

31. Optional: Build the ramp. Construction details are shown on Drawing Page 15. This ramp is
intended for people use, not heavy machinery. It is made of a wood core (2x4’s and plywood),
steel side stiffeners and a front catch plate. (2x6’s can be substituted in the core for more strength
(and more weight). 1/8” thick steel can be substituted on the sides for less weight (less strength).)

This ramp is designed to be stored under the trailer and slide in and out from the back. The 2, 1/2"
round bars (guide pins) welded to the catch plate (shown on the drawing and in the picture above)
slide in the optional angles welded under the trailer frame. The catch plate hooks are designed to
grab the back channel of the trailer frame for easy loading and unloading. The picture above
highlights the ramp catch plate, the guide pins and hooks. The holes in the plate are for screw
attachment. For greater strength, weld the catch plate to the side stiffeners.

To secure the other end of the ramp in the stored position, drill 2 holes in the back c-channel and
weld nuts inside. Drill matching holes in the end of the ramp and attach with bolts. Wings (like a
wing nut) on the bolts make storing easier. Tying the bolts to the inside of the ramp is nice to keep
them from getting lost. Be sure to secure the bolts so they won’t vibrate loose as you travel.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 12
 To make the ramp easy to grab and pull out from under the trailer, add a couple of 1 x 2 pieces of
wood just inside the back end for handles to pull it out.

Note: If this ramp is used with a flush top deck option, the decking (trailer floor) must leave a little
space, between the back channel and the wood so the hooks can get around the channel. The
hooks on the catch plate keep the ramp from sliding off the back of the trailer when it is being used.

32. Optional: Attach a tool or storage box. A tool or storage box can be added and mounted on the
front section of the trailer if desired. The picture below shows a mounted box. Boxes for this use
can be purchased at numerous variety stores like K-Mart, Wal-Mart, Target, etc.. Rubbermaid and
others make weatherproof plastic boxes that will work. Most of these can be fastened by bolting
through the bottom to the trailer. For better support, bolt a piece of plywood to the tongue triangle
then bolt the box to the wood. To waterproof it, use a little sealant around each bolt.

6x12 Shown with Optional Toolbox, Tie-down bars and Ramp

33. Optional: Build trailer sides. If sides are desired, they can be added in a number of different ways.
If you need sides, consider the height and strength required. Also consider if the sides need to be
permanent or if they must be removable. If removable, consider the process for taking them on and
off. Also consider weather proofing of the interior if that is desired.

In the plans several variations for sides are shown, however, because of varying needs for sides,
only a few specifics are given and exact materials are not listed. If sides or a top are desired, use
these instructions as recommendations, then plan and incorporate sides as desired. In particular,
we recommend completing the main trailer then measuring and fitting sides per your needs.

To add sides, measure and build from the completed trailer frame. Take note of how the tailgate or
back door will interface with the sides. Weld (or bolt) the uprights at the corners to give stability.
We recommend welding if the sides aren’t removable. Be aware of the axle and its positions when
locating the uprights – they may limit axle movement. Sides shown in the drawings are made from
2” x 1” x 1/8” rectangular steel tubing and 2” x 1.5” x 3/16” angle, with plywood as an inside liner.
Optionally, the framing can be made from any materials desired. Strength and use must be
considered when choosing materials. Triangulation my also be considered and used for rigidity.

Use the included drawings as reference to formulate a plan. There are several concepts presented
to give ideas and some dimensions are shown only for reference. Since you are building your own
trailer, you are obviously smarter than average in this area, so figuring out sides with the help of the
included drawings will be fairly easy.

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 13
 Depending on what you want, the frame may overlap the plywood or not. The plywood may want to
be at the same height as the frame, or extend slightly above. If a top is desired, an angle iron piece
can be used over the top edge of the plywood to make a secure mounting surface for sealing (see
picture). Length of the uprights may be different depending on the way the top is handled.
For aerodynamic efficiency, add the half-pipes to the front (as shown in one drawing view). These
can make a significant aerodynamic effect – especially since the trailer will be immediately behind
the tow vehicle. Rounding just the edges can reduce wind noise and increase efficiency.

For access to the inside space, consider a gate or door and whether that should slide in, hinge to
the right, hinge to the left, split in the center, bolt-on, etc.. When considering a gate or door, make
sure the sides accommodate its attachment. Latches and hinges of many varieties are available to
meet your needs. Shop around to choose the best approach for you.

If you use the included option for the hinged tailgate/ramp, the sides will need to accommodate a
connection from the lifted gate to the sides to secure it for traveling. That can be as simple as a
couple of holes to allow a pad lock to be latched through.

34. Optional: Build the hinged tailgate/ramp. Layout the ramp as shown in the drawings. Note areas
that are chamfered. These may be used or not, depending on your preference. For light duty,
thinner (wall thickness) angle iron can be used. For heavier duty, use thicker angle.

The top of the ramp can be expanded metal or plywood. Expanded metal offers visibility from the
rear-view of the tow vehicle, and less aerodynamic drag. Plywood is cheaper.

The hinge is created by welding tabs to the gate, and opposite tabs to the back channel. For best
function and set-up, support the tabs and tailgate in place with the rod through the holes, then tack
weld the hinge brackets in place. Remove the rod and back tailgate, then finish welding.

Several options are available for securing the tailgate up-right for travel. Some people like a spring
assist to lift the tailgate; some prefer simplicity. Some prefer hitch pins, while others like catches.
Many options are available, so consider your needs and build to suit. The simplest method is an
angled brace pinned from the trailer side to the tailgate. This method also keeps the top of the
trailer flat if sides are not desired. Use one, or one each side for greater stability.

35. Optional: Attach a spare tire. There are two easy locations for a spare tire (if you wish to have
one). The first is on the tongue – there are several bolt-on products available to accomplish this.
The second location is under the back of the trailer – particularly if the ramp option is not used.

Another option for a spare is to have the trailer wheels and tires match those of the tow vehicle.
That way, if the tow vehicle carries a full size spare, it could be used for either the trailer of the tow
vehicle should you need one.

36. Paint and finish the trailer to reflect your own personality. We strongly recommend taking the time
to protect your investment. Prepare the steel by sandblasting, then use a good primer and paint.
We recommend a 2-part epoxy based primer available at most industrial paint centers. (Powder-
coating the frame can be even better than paint, but requires special equipment. Usually, it’s fairly

Utility Trailer Construction Instructions, Copyright © 2003, Mechanical Elements.com, All rights reserved. Page 14
 economical to have done.) Use an industrial outdoor rated primer and paint on the wood parts –
house paint will not last very long. Consider where the trailer will be used when selecting paint.

37. Hook it up and take it for a spin! Enjoy it, you’ve earned it!!

Options:
Several options are included with these plans. Things like motorcycle stands, various tie-down
options, multiple sides ideas and ramp options. Consider your needs and incorporate the options that
best fill those needs. You will likely have the trailer for a long time, so take a moment and think about
what options will be best. You’ll be glad you did.

Towing Tips:
- Secure all bolts and fasteners in vibration resistant ways – use things like Nyloc nuts, Loc-tite, cotter
keys or wired nuts. Be sure the methods are appropriate for the situation.
- Check bolts, fasteners, lights and brakes prior to towing.
- Inspect the trailer regularly to assure there are no cracked welds, loose bolts, or other issues that can
create problems.
- Inspect the spare tire (if used) to be sure it is inflated properly and in good condition.
- Double-check the hitch to be sure it is connected securely.
- Use tow chains and secure them to a sturdy part of the hitch.
- For stability, distribute the load on the trailer evenly – not disproportionate on one side or the other.
- Again, for stability, the trailer load should be such that 10% - 20% of the load is on the tongue.
- If you have a problem with swaying or instability, re-distribute the load. Most instability issues come
from improper trailer assembly (things not lined up or square) or from improper load distribution.
- Don’t overload the trailer. Also, be aware of the towing limits of the pulling vehicle and the hitch.
- Don’t overload the tires. Tires on trailers often have a lower capacity than the axle they are mounted
on. This is a great way to have a blowout.
- Secure the load so it won’t shift or move in transit. Keeping a low center of gravity is also good.
- Double check tie-downs, tarps, ropes, etc. to be sure nothing will be “flapping in the breeze” or
dragging the ground.
- Set tire pressure appropriate for the load. When is traveling empty, tire pressure may be reduced to
10 or 15 psi. This will allow the tires to absorb bumps and other anomalies, keep the trailer from
bouncing around, and shaking the tow vehicle. Full tire inflation pressure is needed for a full load.
- If the trailer has high sides or a tall load, avoid traveling when high cross winds are present.
- Allow added distance for acceleration and braking. Even if the trailer has brakes, it can take more
distance to stop.
- Allow more girth around corners – take the corners wide – to avoid hitting the trailer tires on a curb,
because the trailer takes a shorter radius than the tow vehicle. Also, the longer the trailer, the more
space it takes.

For more information about trailers and towing, http://www.synthx.com/articles/articles.html has links for a
couple articles about trailers.

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