Wooden Bar Clamps

[greg Forster]

I'm going to make some wooden bar clamps(similar to CW) , 3-5 ft. lengths; looking at soft maple, ash, yellow pine(nice clear stuff), price-wise all around $3.00- pros /cons? I think I'll make wood screw and tapped piece from maple.

thanks

something like this, bar 2" thick, 3" wide; haven't worked out the notch angles ,etc- but this general idea -leaning toward Ash unless I hear different

:201743

[ray hampton]

I like this idea but want to see more pictures, are the part that hold the screw heavy enough

[john brenton]

Yellow pine might be a good idea for the head and perhaps fixing a piece onto the business end of the screw as the pine is soft enough not to mar the wood you're working. Pecan/hickory might be a good option for the body as well. I've never looked into it before. Whatever you decide to do please let us know. I'd like to make some myself. The ponies are just fine, but I'd like to make them just for fun.

[george wilson]

We had clamps like that in the Cabinet Shop in the museum. We use some I made in the harpsichord movie. I'd certainly use a good hardwood throughout,or the bars will flex and bow your wood that you are trying to glue up. Need hard wood like maple to thread,too. Don't worry about marring your work. Use a soft wood scrap if necessary.

[Steve Friedman]

Funny thing about these threads. My son bought me two clamps that look exactly like the drawing for Father's Day. I have no idea what to do with them, but wondered about that design. I can post pictures tonight so you can see the details, but they seem pretty cumbersome and possibly user made. What were they typically used for? Seems to big to be useful for cabinetry. Looks like it came off a farm. By the way, is there a wooden pad that's supposed to fit onto the end of the screw? The two that I have are nearly identical, with notches every couple of inches. But then one of them seems to have a bunch of extra notches - so that there is one every inch or so. The notches were rounded to match the shape of the metal piece.

Sorry to hijack, but I was just about to post about them because I was clueless.

Thanks, Steve

[Bill Houghton]

The clamps I've seen around here - not many of them, granted - have been Douglas fir. Yellow pine would be similar, from what I've read of it.

[greg Forster]

Thanks for all the comments;
Steve , like to see photos when you get a chance

[Tony Joyce]

This thread may also be of some interest.
http://www.sawmillcreek.org/showthread.php?3786-Real-Wood-Clamps

[Steve Friedman]

Greg, here are some pictures. The dimensions are:

Overall length 31"
screw diameter 3/4"
Bar is 1-5/8" wide x 1-7/8" deep
screw hole locations - 1-1/8" and 2-1/2" from bar
movable arm is 3" deep x 4-3/4" tall
Fixed arm is 4" deep x 2-1/4" tall

I assume you can see the through tenons attaching the fixed arms. The two clamps look like a set, but one has two dowels in the tenon and the other has only one.

Hope this helps. Still curious to know what these were used for and the time frame.

Steve

[greg Forster]

Thanks Steve, very helpful. Your clamps have some design features/refinements I will work into my design. Hopefully by end of Sept. I will have some clamps to show- in the midst of moving 650 miles now; plus need to build a screw box and a few other tools to make some tools once I get settled in.

[Steve Friedman]

Good luck. Let me know if you want close-ups or dimensions of anything specific.

[mike holden]

Greg,
I may be wrong, but I would think that the strap and cutouts on the bottom of the beam are backward. If you applied pressure from the screw, it would simply push the block back as drawn?
Mike

[harry strasil]

I can't give you a time frame Steve, but they are carcase clamps and the old timers used a short piece of scantling with a depression for the end of the screw to fit into with a little lubricant of some kind, probably beeswax in the depression. You will notice how far the double mortices are from the end to prevent break out, on some of these you will also find a wagonbox rivet crossways near the end with a rivet burr on the peaned side to strengthen the end against break out. As hide glue was the glue available at that time period, the mortises were generally not glued as hide glue doesn't react well to shear pressure as these mortices would be subject too.

The old time WWers called them CRAMPS, and if there was a sliding section for the threaded part to push on, it was referred to as a Tommy Bar.

[Brendan Dahl]

Another source for inspiration:
http://woodgears.ca/clamps/jh_barclamps.html

[Steve Friedman]

Thanks Harry,

Wow. It seems awfully clunky for something with a maximum opening of only 24"! Do you know if they were typically manufactured or did everyone just make their own? Parts of mine seem manufactured, but it's not as finished as I would have expected, which is why I thought user made.

Thanks.

Steve

[harry strasil]

Clunky, nice way to describe the technology of the time, especially if nothing better was available. I imagine user made, with the hardware boughten from a competant smith, Not as Clunky as some examples I have seen.

[harry strasil]

Some of the first commercial bar clamps were similar to the Jorgenson pony pipe clamps, you purchased the hardware and furnished the wooden bar which was a 2 by 4, and cut square notches in the back side for the movable jaw to catch in.

http://img.photobucket.com/albums/v81/irnsrgn/wood/oldcramps004.jpg

[greg Forster]

Mike, I don't know for sure, sometimes my ideas are confused; I added a new, improved? drawing with what I think would happen "force-wise" (Greg, who didn't survive the 1st year of engineering and 30 yrs. later still perplexes and irritates architects and structural engineers by drawing proposed solutions on wall studs or in the dirt- if I don't have a building close-by)

Harry, the rivets interest me - any pictures ?

201940
http://www.sawmillcreek.org/images/misc/pencil.png

[harry strasil]

your slots are backward greg, the force is from between the stop and screw, not from the back side.

[greg Forster]

Thanks, Mike and Harry - it has finally made it through my dense skull; the entire lower jaw mechanism wants to push "downward"; I had a confused thought were the wooden jaw pushed down and the metal bracket pushed up and forward



201949

[harry strasil]

Greg, just think of a 2by4 with a 1.5" hole thru the wide side in one end centered 2" from the end. To keep it from splitting out you drill a 1/4" hole centered and all the way thru the narrow way, centered between the edge of the hole and the end of the 2by, and use a 1/4" by 4" carriage bolt to keep it from splitting out.

Hope this helps!

Jr. who started his blacksmith apprenticeship at the end of the era when things were still made mostly of wood and reinforced with iron straps and rivets or bolts.

[Peter Cobb]

Just last week I saw a youtube video "The teen woodworker" on this very style of clamp. Used dowels instead of straps, but same idea.

http://www.youtube.com/watch?v=OQFVzq41zFA
Perfectly happy to epoxy everything together, he is.
Cheers,
Peter

[Adam Cherubini]

Hi Greg,

I've had good luck with the taiwanese wood threading kits from Woodcraft (and harbor freight and other places). The 1" 6tpi or 8tpi is good. The 1-1/2" 6tpi not so much. If I understand your intentions, I would place the centerline of the screw close to the beam for ultimate stiffness. In the picture above, the head has 2 holes for the screw.

Tho I have a couple of these clamps, I use pipe clamps and PVA for long glue-ups. Tho I do this infrequently. For manageable sizes, I use HHG rub joints. For table tops I use the PVA and 10-20 clamps and lots of pressure.

While you are making clamps, I recommend you fab up some big hand screws. I made a set of these years ago and have used them continuously ever since. The 1" thread kit is perfect for these. Check out Jay Gaynors book "Tools: Working wood...." for inspiration.

For everyone else, those bog wooden hand screws do things no other clamp can do. And their purpose, I think, is slightly different from normal clamps. I use mine to hold work while I do stuff to it (as opposed to holding parts together during gluing). Mine are like a poor man's pattern makers vise. (If you get my drift).

Adam