# Clamping pressure



## kweinert (Feb 27, 2019)

In the segmenting work I do I have a very simple jig that I use. It's just an L shape glued down to a base.

I cover the base and front edges of the jig with packing tape and right now I'm using basically a spreader bar from the side to ensure all the edges are aligned and a bar on top to try to keep it flat. I'm also pressing against the end to hold the pieces together.

If you've seen any of my recent posts in @ripjack13 's segmented pen swap you'll have a better visual on what I'm talking about.

Now to the point: right now all these things are held in place with regular clamps. I'm working on a design in my head to improve this jig and I'm thinking that I want to use both push type clamps and hold down clamps in the redesign.

Sort of like these:












Now, obviously, I need to work out the physical sizes that will work for me. The question I have for you folks is how much clamping pressure would be reasonable.

What I'm clamping will range from pen sized like I have now (2" wide, 12" long, 3/4 thick) to feature segments for bowls (6" wide, 18" long, 1 1/2" thick).

The push clamps are for both side and end pressure and the hold downs are for top pressure (obviously :)

I'm seeing values for holding pressure from 100 - 500 lbs (or more) and while I want something that will do the job I don't necessarily want overkill on it either.

So, your thoughts on any resources for determining the pressure or personal experience will be greatly appreciated.

Also thoughts on a reasonable place to get them are also appreciated - the above pictures were borrowed from Amazon :)

Thank you.


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## ripjack13 (Feb 27, 2019)

I have a bag full of those things. somewhere in my garage. I was going to use em for my chop saw table, but I have yet to build it.
I got em from a job I used to work at and they got em from McMaster Carr, so they're the good ones...


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## Gdurfey (Feb 27, 2019)

@kweinert, I was looking through the woodcraft catalog over Christmas at similar clamps and am trying to remember if they had "approx." clamping pressure in the description. Seems like either rockler, woodcraft, or similar catalogs might give you some ideas. Honestly on my old bar clamps when the bar starts bowing and such, I wonder how much pressure is really there. I was also looking at clamps to integrate into a workbench top with t-track type of guides crisscrossing. 

Interested in what you learn.


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## kweinert (Feb 27, 2019)

Gdurfey said:


> @kweinert, I was looking through the woodcraft catalog over Christmas at similar clamps and am trying to remember if they had "approx." clamping pressure in the description. Seems like either rockler, woodcraft, or similar catalogs might give you some ideas. Honestly on my old bar clamps when the bar starts bowing and such, I wonder how much pressure is really there. I was also looking at clamps to integrate into a workbench top with t-track type of guides crisscrossing.
> 
> Interested in what you learn.



On the Amazon side they do give a clamping pressure but I don't have a good mental image of what that really means:

www.amazon.com/XRPAOWA-Toggle-Holding-Capacity-Stroke/dp/B074RYNVYM/ref=sr_1_5?keywords=push+clamp&qid=1551299622&s=gateway&sr=8-5

*XRPAOWA 4 PCS Toggle Clamp 301AM 99lbs Holding Capacity Stroke Push Pull Action Hand Tool Light Duty Toggle Clamp Tool*

Is 99 lbs a lot? Will that be enough to create a tight enough glue joint across my application?

I'm pretty sure that the 100lb hold down is sufficient to keep the pieces flat - but if there's not a massive price difference I will probably go with a higher one because more pressure there doesn't have a negative affect. 

Squeezing the joint though, could be an issue if the pressure gets too high.

Just trying to learn and absorb knowledge from others here.

As usual I'm probably over thinking things.

Reactions: Informative 1


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## ripjack13 (Feb 27, 2019)

You have to remove the https :// at the beging of the link, in order for amazons pages to show up...


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## Nubsnstubs (Feb 27, 2019)

I've used two 15 pound pieces of lead to secure glue block to some of my blanks when I don't have enough thickness to incorporate a tenon. 30 pounds did the job on a 12" solid blank, maybe 15 pounds total.

The clamps you show are copies of De- Sta-Co clamps. They'll give you plenty of pressure to do what you want to do. At one time I had over a hundred in use when I was in business. Good clamps for whatever use you need, if you can figure how to make it work. .......... Jerry (in Tucson)

Reactions: Thank You! 1 | Agree 1 | Informative 1


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## gman2431 (Feb 27, 2019)

I've used these clamps, the de sta cos mentioned above, for fixturing up glue ups when fabricating solid surface. They work great. The rubber tips will compress some and there is a range of sorts pressure you can exert.

Reactions: Thank You! 1


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