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By terrawooddesign, Apr 11 2020 04:56PM

Project: Wall mounted clamping system

Designed & fabricated by: Chris Grohs & Nichole Sheaffer

Date published & produced: March 2020

Introduction & purpose:

An essential role to furniture making and home installations is the role of a clamping system. As there are many clamping systems to choose from, the main and dominant goal of the panel system is to produce even compression and finish with a panel that rests equally in one plane [ flat and simple ]. While box clamps atop a flat workbench work well, the space that is taken by the system while set to cure will not produce efficiency in a small workshop [ this is the case of the Terrawood shop ]. With the right project on the boards, such as cabinets or a closet build out, putting a 12-24 hour clamping system on the table can put our 1,000 sq.ft. shop on hold. This can’t happen when there are multiple panels to prepare and process. There are a few clamping systems pre-fabricated and available for purchase online, simply Google “panel clamp” or go to as a start for your search. Also, there is another clamping system plan at that features bar clamps as opposed to the box style clamps featured in our shop plans. We referenced the plans on Rockler’s article, “Wall-mounted Plywood Panel Press Project” (the authors are not listed) to get the main construction for the system. However, not all elements were compatible for our shop, so we altered the details to develop a system that worked with what was already present in the shop and added to that. You too, might come to a point where you realize already present shop gear could and should be used before spending resources to acquire new shop goods. Use your predefined skills to expand your tools and you’ve got it- a new wall mounted clamping system.

Grab some coffee and here are the details:

Supplies needed (tools are not listed, that’s your job):

Qty listed as (x)

(5) 3/8”-16 ‘all-thread rod’ @ 6’ length

(3) 1x3 -1/4” steel square tubing @ 8’ length

(2) 1x2- 1/4” steel square tubing - See step 19 for use and measurement

(1) can of self etching metal primer

(2) packs of shims (ideally composite shims to withstand the compression)

(26) 3/8” lock washers

(78 - a.k.a. a big ass box) 3/8” -16 compatible nuts for the all-thread rod

(26) 3/8” washers

(2) 1/2” plywood ripped to 3” @ 8’ length

(~14) 5” screws with a flat head- we used Spax

(6-8) 2” wood screws

(7) 8/4 x 7” @ 8’ length hardwood ( we used Ash, what you are trying to accomplish here are the 26 cauls, this dimension number could also change depending on your desired height - SEE STEP 7).


(1) 3/4” x 9 x 8’ surfaced and dimensioned hardwood lumber

- (7-10) working box clamps. (We used (7) 40”ish box clamps)

(1) container of sealer and finishing applicant

- (2) rolls of high quality packing tape ( don’t skimp on this part. we used TREX)

(26) through threaded Star Knobs compatible with 3/8”-16 all-thread rod (we picked ours up in bulk from Amazon ‘SHOCKING’ we know.)

That’s it for the list. You’ll have to have some certain shop tools, but those will be listed along the way as we go step-by-step. So, be certain to scan through the details. We made it easy and listed the TOOLS in bold and all caps. Also, I’m not including the math on certain areas, mainly because you are smart and you may want to apply different measurements to fit your needs.


Step 1. Find a working space on your wall that will cover an area of approximately 5’ x 10’. More space if you have it available and like some extra elbow room. Clean all metal parts of oil residue.

Step 2. Define (12) spaces on 2 of the steel tubing pieces, this will equal (13) posts per 8’ tube. Use a DRILL PRESS to properly drill a 3/8” hole continuously and squarely through the marks on your steel tubing. * Note that the top tube has holes directly in line with the center, while the lower tube is off set in favor of the bottom. The key is to have the surface in which your glue-up rests on your box clamp to be HIGHER than that of the All-Thread on the lower assembly. Hint! Define your points with high accuracy.

Step 3. Define all wall studs on your chosen space. Mark, Transfer, and use the DRILL PRESS with a bit appropriate to the 5” screw threading (listed in the materials) and drill out the marks on each steel tubing. The 2 steel square tubes should lay out exactly the same. Always measure starting from the same end.

Step 4. Use a METAL SAW to cut the All-Thread at 10” pieces. Our system accommodates a glue-up with a max thickness of 3”. If you choose to go bigger, cut the All-Thread to equal that additional measurement. ie. if you wanna have a 4” max thickness cut 11” rods. I’m sure you get the picture.

Step 5. Set your 10” threaded rod through all 3/8” holes and apply the lock washer and nut flush to the backside and WRENCH down the nut on the topside keeping the rod flush with the backside nut. You may apply this in whatever order you choose just be certain that the rod is not proud of the nut on the backside. Get it tight and make sure it’s square.

Step 6. Spray down the entire front side, including the rod and nut, of each assembly using your FINGER. You can do the backside if you choose.

Step 7. DRILL holes into the 1/2” plywood backing according to the bolts that stand proud on the backside of each assembly [this should be a pair of equal backers if you did it right]. Use whatever tool you would like. The goal is to have a backer that allows the nuts freedom to float away from the wall while accomplishing a flat even surface between the wall and your assembly. Secure this temporarily with tape. This is now a part of the assembly.

Step 8a. Flat, Square, and Parallel. Map out the outer parallel edges of your (2) assemblies on the wall with a defined line. Double check that all marks are square. This can be at whatever distance is best for your project applications [we went for 40” which was defined by max capacity of our working box clamp] . Start with the bottom first and mount your assembly according to your defined line. Use your Spax like screws to get this tight into the stud. Sight and shim where necessary.

8b. Line up the top and secure that assembly as you did the bottom. Sight and shim where necessary. Double check your work with a NYLON LINE.

HINT! Take your time thinking through the proper steps to hang this to your wall. Double check your studs and always mark starting from the same starting point ( in other words- dont flip your ends). Use as many tools as you need to get this up right. A few tools might be: 6’ LEVEL, SELF LEVELING LASER, STRAIGHT EDGE, EYES, SQUARE, CHALK, PENCIL, WOOD PROPS ( cut to equal and exact distance between the top and bottom to act as rests )... I’m sure there are more. Use your skills. Any bow warp or twist in the system will translate exactly to your glue-up panel. Unless you don’t care or are going for that sort of thing, then by all means, build it with a warp or twist.

Step 9. Build the cauls. Mill max thickness and about 3” depth (wide) with the proper length. Plan to end at final length of the total height of your entire wall assembly. In other words if from the very top to the very bottom = 45”, then that’s your final number. Get it close, let it rest, let it move. The more stable your wood, the better and longer lasting your final tool will be. * sand off the mill marks. Tools that you should use: JOINTER, PLANER, TABLE SAW, CHOP SAW, TAPE MEASURE, FLAT SANDER of some sort.

Step 10. Once your cauls are all exactly the same, square, and stable now its time to remove the material for the 3/8” slots where the All-Thread will rest. One end will have a groove that extends further along the center face of the caul than the other. This is to allow ease of removal and insertion. The shorter groove sets on the bottom and the longer is at the top. See the illustration for measurements. So much easier than explaining it. Can you imagine how much easier it will be to apply or remove these cauls? Tools that you might use for this: DRILL PRESS, TABLE SAW, TENONING JIG

Step 11. To the rear cauls only, use a ROUTER to remove a gap along the slot on the opposing side of the clamping surface. Use an appropriate straight bit that will easily clear out the material and exceed the total diameter of the 3/8” nut (about 3/4” but double check that this is true). This allows space for the nut to nest so that the flat surface of the caul can rest along the flat surface of the steel assembly. Again, there IS an illustration.

Step 13. Chamfer the edges ( however you choose, just remove the material to tighten the applied clamping pressure) of the caul’s clamping surface. We used a 3/4” round over bit on the ROUTER TABLE. Another option would be a 45deg. ROUTER BIT.

Step 14. Congratulations your cauls are all cut and complete. Try them out! IF the don’t clear upon top to base insertion, you may have to go back and cut the 3/8” groove to be longer.

Step 15. You’ll want to sand and smooth all of the surfaces. Any SANDING MACHINE will do.

Step 16. Seal and finish all of the cauls on all surfaces.

Step 17. Once cured, tape the clamping sides of all cauls with your heavy duty clear packing tape.

Step 18. Secure the back clamps with washers and nuts. These need to be exactly SQUARE with the base of the bottom assembly. Once in place, now is a great time to take a straight edge across the surface of the cauls to double check how accurate you were at hanging your assemblies square and flat. IF the STRAIGHT EDGE is not touching all surfaces of the cauls evenly you’ll have to find your error and correct this.

Step 19. Leaving your outer/frontside clamps to the side for now, it is time to assemble the base. The base is key. This is the resting point for all of your clamps, which will hold the weight of all glue-ups that make their way to this system. So, it has to be strong, flat, and square to the rest of your wall clamp assembly. Start by drilling holes through metal with your DRILL PRESS that will accommodate the threading of your 2” wood screws ( on the materials list ). These holes should be spaced out equally along the center line. (This is where you will eventually attach the 3/4” hardwood plank.)

Step 20. Now for the legs. You may have to get a bit innovative if you don’t have a WELDER. There is definitely no wrong way of doing this, so long as it’s stable and can support a fair amount of weight. As shown on the Rockler example, they have a system with a wall mounted platform made entirely of wood and can certainly be applied to this application. Here’s how WE did it: we developed (2) welded T-base legs ** that carried adjustable bolt levelers on the floor. These were then welded square to the 8’ pre-drilled square tube that stands at a defined height according to the lower base of the wall clamps. ** To find the overall height of the base, measure from the base of your wall clamp assembly to the floor accounting for your hardwood platform and your leveling system. Why we chose this method over the wall mounting platform: we wanted to develop a system that could withstand the weight of a 3”x 36” counter or table top at 8’ length. A wall mounted system would be sufficient for thinner material. Be sure to check out the illustration for a simple perspective.

Step 21. Using your FINGER spray the base assembly with a self-etching primer of your choice.

Step 22. Now it’s time to line up and secure the FINAL piece of your base wall assembly. Dry fit your 3/4” dimensioned hardwood plank between the base and the clamping system. Line up the face of the lower assembly to the back of your metal base. Line up the rear of the hardwood plank to the rear of the base wall assembly. This should fit tight and secure. Adjust your levelers until you are satisfied with the overall rigidity and squareness of the base.

Step 23. With the platform and base dry fit in place, spin one star knob onto any lower All-Thread rod until it touches the platform. Mark the center point of the threaded rod onto the platform. At this point you will notch out a space for your knob to fit and tighten to the minimum amount of material clamped in the system. Make a template and trace this at each center point of the All-thread rods on the base. Before removing the plank for sawing, double check that your work makes sense. IF its all good, remove the plank and remove the notch at each point. HINT: If you don’t remove enough material the knob will bind on the platform when doing thinner glue-ups. If you remove too much you will lose structure and expose the metal base below.

Step 24. Sand, seal, and finish your platform.

Step 25. Fit your base assembly and platform in place as you had before. Now secure the platform to the base from beneath with your wood screws.

Step 27. Attach all star knobs to the tips of the All-Thread

Step 28. Insert the remaining cauls with clamping side facing in.

Step 29. Crank in your star knobs to their max and check the space in between the cauls for minimum desired thickness and clearance.

Step 30. Test it out! Congratulations. HIGH FIVE