How to clamp a triangular brace?

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Forum topic by manuka posted 02-07-2015 06:16 PM 1517 views 0 times favorited 12 replies Add to Favorites Watch
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30 posts in 744 days

02-07-2015 06:16 PM

Topic tags/keywords: clamping hardwood triangle

I nearly lost it trying to glue up these braces late last night. Clamps slipped, screws broke… When I started to want to throw things at the floor, I had to stop.

On the picture the two boards are just standing there, nothing is yet attached. It’s a dense timber so it will walk away from screws unless clamped.

How would you attach these braces?

With the coolness of morning, here are some ideas that came to me. Would appreciate comments on those too as at this stage.
- Forget about the triangles. Use rectangles for these braces. (Not loving this idea for looks.)
- Cut the triangles at a different angles so there is a clamping surface at the top.
- Order some shelf clamps. Those look like they would do the job, does anyone have experience with them? I don’t own them so I’d have to order and wait a week (not a big issue if this is the best way.)
- What else?

Thanks in advance for any thoughts and insights!

12 replies so far

View Fred Hargis's profile

Fred Hargis

3848 posts in 1916 days

#1 posted 02-07-2015 06:23 PM

Cut a notch in each triangle. Use that for your clamps. The notch would have a side parallel with the front and bottom of the triangle.

-- Our village hasn't lost it's idiot, he was elected to congress.

View Dan658's profile


93 posts in 693 days

#2 posted 02-07-2015 06:30 PM

I would glue and clamp the two boards together first, and then after the minimum clamping time, I’d place the triangle braces in with 2 part epoxy.

View TheFridge's profile


5682 posts in 909 days

#3 posted 02-07-2015 07:20 PM

Yup. Cut a small triangle in you triangle so the clamps sit good

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View dhazelton's profile


2289 posts in 1719 days

#4 posted 02-07-2015 07:28 PM

Countersink screws in from the side and bottom.

View firefighterontheside's profile


13097 posts in 1279 days

#5 posted 02-07-2015 07:36 PM

Glue and screw two perpendicular pieces together, then predrill thru corner blocks with a drill bit appropriate for the size of the screw, then move corner piece away and drill larger hole so that the threads of the screw don’t engage the hole. That will allow the screws to pull the two pieces tight together without breaking screws.

-- Bill M. "People change, walnut doesn't" by Gene.

View Ghidrah's profile


667 posts in 645 days

#6 posted 02-07-2015 07:48 PM

It looks like if you had a couple 4, 5 or 6” deep C or bar clamps you could glue the right angle together 1st then cut a couple blocks long enough to cut a 90° notch in them deep enough to retain/restrain both sides of the jig in place opposite the braces. Glue, place and clamp the braces to the restraining V notched blocks and wait.

-- I meant to do that!

View mcg1990's profile


158 posts in 715 days

#7 posted 02-07-2015 08:03 PM

Brown is what you’ve got, red is a cut block, green are clamps.


View daddywoofdawg's profile


1006 posts in 997 days

#8 posted 02-07-2015 08:15 PM

drill vertical holes in the “braces” maybe 2,then 1-2 horizontal to screw into the bottom of the shelf. glue and screw your braces where you want them then come back and do the same to the shelf.

View Mykos's profile


102 posts in 1217 days

#9 posted 02-07-2015 09:15 PM

I’d be inclined to do what mcg1990 described but even simpler, by using the other part of the triangle brace cutoffs. A loose triangle cut with the complimentary angle will let you put clamps on in both directions.

View SCOTSMAN's profile


5839 posts in 3008 days

#10 posted 02-07-2015 09:24 PM

Why couldn’t you just put a few dabs of hot melt glue onto it and hold for a few seconds till dry then screw away?Once it is screwed up you could if unhappy take it apart and remove-scrape away the H M glue then it should be easy to screw together but I would leave it alone or superglue even.You will only require a few drops of HMG or superglue wait till it’s nice and runny hot then as sai alittle will do you don’t want it seepeing out of the joint all onto your nice clean unburned fingers.Alistair

-- excuse my typing as I have a form of parkinsons disease

View manuka's profile


30 posts in 744 days

#11 posted 02-09-2015 02:46 AM

Wow, guys, many thanks for all the helpful replies!

Even if the method I followed wasn’t the one you posted, I learned from each suggestion. This will be a really useful thread for anyone else looking to clamp triangles.

After cutting one corner as some of you suggested and clamping the first side, I kept the sides square while clamping the second side by balacing clamps from two directions (photo).

View patron's profile


13524 posts in 2764 days

#12 posted 02-09-2015 03:00 AM

rather than all that
a pice of scrap stock say 1×2 cut just short of the hypotenuse side
with 45* notches in it both ends
to clamp to
just have different lengths stored in a box
for future works

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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