3" C-Clamp differences.

bob vaughan

Bob Vaughan
Senior User
While gluing some cleats on table aprons, I had to use a lot of 3” clamps. After the glue-up I had a pile of various clamps on the bench and noticed some differences I’d not noticed before. The majority of my 3” clamps were either “Adjustable” or “Brink and Cotton” I remember some of the clamps having more bite than others but thought little of it. I was using all sorts of clamps from my inventory of small clamps.

Below are some observations I made of the two most common brands of clamps one finds at flea markets and yard sales. I’m showing this so the buyers can be more informed as to what to look for when choices have to be made. Clearly, the Brink & Cotton is the more desirable of the two.

1   clamp a - 1.jpg
Clamp comparisons

1   clamp b - 1.jpg
Pile of various 3" clamps

1   clamp c - 1.jpg
The glue-up. Required my getting creative and using what I had available in that size and capacity range.
 

bob vaughan

Bob Vaughan
Senior User
I looked a little more carefully and did notice that some if the Adjustable clamps had corner bracing and some did not.
 

tvrgeek

Scott
User
My favorites are from Wards and are aluminum. Only have two of them. The rest are so cheap, they say nothing.
 

bob vaughan

Bob Vaughan
Senior User
I've got a pocket hole jig but the aprons on this job required the rigidity of a pressure glued joint. I've used my pocket hole jig to fasten the aprons to a small table top and its handy, fast, cheap, and easy.
1   pocket - 1.jpg
Pocket holes drill for table top attachment.
 

Oka

Casey
Corporate Member
Another thing alot of the clamps you find are not hard steel, so if you cnich on them the jaw actually deflects
 

Hmerkle

Hank
Corporate Member
I've got a pocket hole jig but the aprons on this job required the rigidity of a pressure glued joint. I've used my pocket hole jig to fasten the aprons to a small table top and its handy, fast, cheap, and easy.
View attachment 200099
Pocket holes drill for table top attachment.
Can you talk about that a little furhter?
Why would a "pressure-glued joint" be stronger than an glued and screwed joint?
 

bob vaughan

Bob Vaughan
Senior User
Like all goods, there's good and there's bad. The point of this post was to help a buyer make a better informed decision when choosing between two similar looking clamps. That 3" size and type seems to get a lot of use around my woodworking shop for jigs, stops, and gluing. Some of the 3" c-clamps I used were a little too big but there were so few of them it wasn't a weight distortion problem.

There are other 3" C-clamps available of a far superior clamping force that won't deflect as much. Below is a line up of some 3" c-clamps. The Cincinnati stamped steel on the far left is light and strong but doesn't have the throat depth as the B&C (second from the left). The middle clamp is a cast iron oldie that has plenty of strength but heavy. The Jorgensen 103 has a 5/8" diameter Acme lead screw that gives plenty of pressure for gluing but can dent softer wood. Its good for multiple layers when thick glue needs to be spread out under pressure. On the far right is an Armstrong drop forged clamp that I use mostly for machine shop setups. It is capable of some really strong pressure.

1   clamp - 1.jpg

Below shown the radical differences in 2" c-clamps available . Obviously the Wilton drop forged clamp is for metal working.

1   clamp - 2.jpg

Bargain basement Asian-made C-clamps that I've seen were weak and deflect, their biggest deficit is the floppy, sloppy lead screw fit. When the screw is tightened the work shear slides all over the place under pressure with the lubrication of glue.
 

bob vaughan

Bob Vaughan
Senior User
Can you talk about that a little furhter?
Why would a "pressure-glued joint" be stronger than an glued and screwed joint?
Screws don't seem to give me the consistent squeeze-out for a good continuous glue joint. There's a good adhesion area right around the screw but the further away from that point, there's not the same pressure. Also using screws in the application at hand will take a lot longer if done correctly.

Note the glue squeeze out below. This cleat will have good adhesion and make for a rigid apron on a relatively light weight frame. I wouldn't be so fussy if I were making a picnic table out of pressure treated spongewood from Home Depot.

1   clamp a - 1.jpg

The table frame complete

1   clamp a - 2.jpg

As to pocket screws, they don't use them for butcher block tops and stair treads yet.
 

Hmerkle

Hank
Corporate Member
Screws don't seem to give me the consistent squeeze-out for a good continuous glue joint.

As to pocket screws, they don't use them for butcher block tops and stair treads yet.
That makes sense - with a screw you do only get localize pressure..

As for the butcher block tops and stair treads, don't give them any ides! (there will probably be a new infomercial dedicated to them!)
 

junquecol

Bruce
User
Screws don't seem to give me the consistent squeeze-out for a good continuous glue joint. There's a good adhesion area right around the screw but the further away from that point, there's not the same pressure. Also using screws in the application at hand will take a lot longer if done correctly.

Note the glue squeeze out below. This cleat will have good adhesion and make for a rigid apron on a relatively light weight frame. I wouldn't be so fussy if I were making a picnic table out of pressure treated spongewood from Home Depot.

View attachment 200111

The table frame complete

View attachment 200112

As to pocket screws, they don't use them for butcher block tops and stair treads yet.
Kreg used to have a series of videos on trimming out houses, and yes they did use pocket screws for stair treads, rather than buying treads complete.
 

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