my attempts at homemade luthier clamps

[Tony_in_NYC]

Mario Proulx put together this documented build with lots of go bar action in it. check it out...

http://www.proulxguitars.com/buildup/build1.htm

Martin...for all of the time I have been on this forum, and all of the times I have seen Go-Bar decks used for gluing braces, I could not for the life of me figure out how you glued the long braces without cam clamps(or at least deep throat c-clamps)!
If you will excuse me, I need to go bang my head into the wall a bit. Maybe it will shake my mental block loose.

I had seen that already. Proulx is a hack. LOL Just kidding.

[Kevin Sjostrand]

I don't own a cam clamp either. I just sit on the joint, 300 lbs of pressure seems to be just right :>)

Joking aside, I have had good success with a variety of inexpensive clamps and my gobar deck. To each his own I guess!
But, if anyone has some cam clamps they would like me to inherit, please, by all means, send them to me. I promise I will use them.

Kevin

[Ben-Had]

I don't use cam clamps or a go bar deck for braces. One look at those go bar rods and I could just see me turning the wrong way and the whole thing go flying every which way. That's why I bought a vacuum press:)

Tim B

[kencierp]

Since each time one adds a rod to the go bar deck the relative pressure applied by all the previous rods change -- we Engineers have a problem with that, plus the angular attack/pressure points. But as indicated for some the job gets done in a satisfactory manner. I agree the best solution I have found is indeed a vacuum clamp --- surprisingly easy to make and also very affordable -- here's a thought starter:

http://www.kennethmichaelguitars.com/vacuumclamp.html

[Ben-Had]

Since each time one adds a rod to the go bar deck the relative pressure applied by all the previous rods change -- we Engineers have a problem with that, plus the angular attack/pressure points. But as indicated for some the job gets done in a satisfactory manner. I agree the best solution I have found is indeed a vacuum clamp --- surprisingly easy to make and also very affordable -- here's a thought starter:

http://www.kennethmichaelguitars.com/vacuumclamp.html

Good ole "Joe the Woodworker," that's where I got my stuff and I LOVE IT!

Tim B

[tippie53]

I use both vacuum and go bars . Lets be honest, the amount of force is determined by the length of the go bar rod. i doubt the if you are using a quality ply wood that the amount of clamp weight change is very noticeable.
Also if the joint has integrity and dry fits well , it don't matter . You need about an 8 to 10 lb clamp weight . Using 20 go bars will apply 160 to 200 lbs. It does the job. If you are using a hot hide glue the vacuum bad won't work as well as a go bar .
My take is that your joint mating is more important than the clamp technique . This is a case of choose what works best for you .

[naccoachbob]

Neil, for those screws you're using, why don't you go to a hardware store and pick up some threaded inserts? I think they're open at both ends. You can drill a properly sized hole in the clamp, then screw in the insert with some glue around them. That way they'll stay sturdy in there and your clamps will probably last longer.
Bob

[Tony_in_NYC]

Tony, not that I'm any wealth of knowledge as I'm only on my first, but I'm not sure what you mean about glueing long braces. I used a Go-Bar deck and you just put a half dozen rods or so across the clamp to hold it in place with pressure while the glue dries. Is that what you mean?

I know some advocate clamps and some like Go-Bar decks. In looking at my first build, the Go-Bar deck seemed the most user friendly and least expensive to build. Seemed to me like it takes the place of 10 clamps. There is probably a down side that I'm not aware of with my limited experience.

Sorry if this is a tread hijack.

Mike

Mike,
Sorry if I was not clear. I know how to clamp with a go-bar deck...in theory. Never used one though. What I meant earlier was that for me, if I didnt have my cam clamps, and since I dont have any deep throat clamps other than those cam clamps, I could not efficiently clamp a long brace if I could not clamp it in the center as well as the ends. A go-bar set up will accomplish this. As will cam clamps. When Martin said he didnt have cam clamps, I couldnt figure out how he clamped the center of a long brace. Go-bar deck never came to my mind. Of course...I have an infant who keeps me up so I am blaming lack of sleep.

[nkwak]

Wow - this topic took a bit of a trip, didn't it? That's OK, I don't mind as I'm here to learn.

FWIW making these clamps was more about trying to teach myself some woodworking skills, understanding how things work mechanically and learning how to troubleshoot problems. Apart from hedge clippers and hacksaws I have not worked with wood much at all so I consider myself to be a hapless n00b. Indeed, the last time I used a woodworking power tool was waaaaay back in 1982 for the 8th grade shop class: I made a pig-shaped cutting board with a jigsaw. Now I have a 9" band saw in my basement that I'm still learning to use.

That being said, for this project I used a $10 gents saw and a $5 yellow plastic miter box with a bottle of Titebond and a workbench with a vise that I inherited from my home's previous owner. It wasn't nearly as technical as when I constructed my as-yet untested birch plywood semi solid outside mold for my first build but I figured that these would at least come in handy for working around the house! ;)



The picture above illustrates a couple of problems I've been trying to resolve. The first was obvious: how to understand how the flexing of a piece of wood against another could generate sufficient force to clamp tightly. I learned that the moving jaw has to wedge itself against the shaft to keep it from moving along the length of said shaft. This is attained by rocking the jaw back slightly and spreading the "mouth" on the moving jaw until the opposing jaw surfaces are parallel to one another. I learned that there had to be a little "wiggle room" and that having a soft clamping surface (namely the cork padding on the jaws) actually played as big a part as any measurement. I'm hoping that little realization helps me work through any problems I may encounter down the line in my first build.

BTW, the second problem is a little less obvious: how to fix things that kids break. I dislike the idea of buying new things when they get broken - especially furniture. I'm no Mr. Fix It but I guess the Man Upstairs thinks I need to be or else he wouldn't have inflicted two boys upon me and my wife! :0)

Anyhoo, back to the sidetrack: why make clamps and not a go-bar deck? Well, the picture of the broken dresser should partially explain that: the kids would break it. Besides, I don't really need it since my build isn't taking place in my home; I'm just prepping things (tooling up, "getting jiggy" and whatnot) here at home and transporting them over to my friend John Kitchen's shop where he has a LOT of tools (including a go-bar deck) but he's lamented that he doesn't have enough clamps. I'm beginning to realize that there's not a lot I can do here since my home's not fully climate controlled - the RH can drop into the low 20% range during the winter.

[Ben-Had]

Now THAT's, a sweet looking box:)