Thread: Wooden clamps

I will await with bated breath for the AWR article Ian.

George

I think this issue of AWR could be a sell out. I think they should up the print run.

Regards
Paul

Originally Posted by Bushmiller

I think this issue of AWR could be a sell out. I think they should up the print run....

Would that mean I get a bigger fee?

Cava, I hope it is explained clearly enough in my articles so that anyone keen to make big bench-screws will be able to follow it easily enough. You do need a wood lathe (or access to one) to make the body of the tap, and a router to cut the external threads, as shown in the thread I linked to, but it's all pretty low-tech, really, and a lot cheaper to DIY than fork out for a ready-made one! If you'd been able to come to the Brisbane TWWW show, you would've been able to see it all in action...

Cheers,

I think I get the jist of it Ian.

Tap first and then the screw. Whilst I do not have access to a lathe, I don't think it would be that difficult to improvise a piece of large dowel to be the tap.

Originally Posted by IanW

Would that mean I get a bigger fee?

I would not be aiming to buy any more boy's toys on the strength of it just yet .

Regards
Paul

Originally Posted by cava

I think I get the jist of it Ian.

Tap first and then the screw. Whilst I do not have access to a lathe, I don't think it would be that difficult to improvise a piece of large dowel to be the tap.

True, just about anything in a sound hardwood would do. However, remember the tap diameter is the minor diameter of the thread, so you will also need some dowel that is the diameter of your tap plus 2x the thread depth, i.e., for a 2 inch screw, the tap diameter is about 1 3/4 inches (thread depth of about 1/8" works well in these sizes). If you can purchase hardwood dowels of that diameter, you will be good to go.

I'm all for improvisation & figuring out low-cost solutions to problems. Something you will need to consider is how to fit an expanded section or 'boss' to your dowel screw so it looks like this: Bench screw.jpg
The boss serves two functions, it creates a shoulder to pull against the vise jaw, and also gives you lots of 'meat' to put a good-sized handle-hole through. If your handle hole is too large relative to the screw diameter, it is liable to split the screw shaft when you clench your vise up tightly.

If you want to get into serious wooden threading, it's a great excuse to get yourself a lathe...

Cheers,

Originally Posted by IanW

If you want to get into serious wooden threading, it's a great excuse to get yourself a lathe...

Cheers,

Yes, but it is easier to hide a chisel than a lathe.

Hey, Hey. What's with this negativity? What you need is a little bit of lateral thinking. All women love a bit of wood. Hold on... that didn't come out quite the way I meant. What I meant was they just love wooden bowls to put everything from fruit to knicknacks into.

You would be buying a lathe so you can make things for SWMBO to decorate her house and make it a real home. In those precious few moments when the lathe is idle you may be able to knock up a timber screw that could be used on a bench out of off cuts from timber turning for such things as bed side lamps.

Now it would not be an easy task to do all that with a chisel, even if it is in stealth mode.



Regards
Paul

I like the way you think.

Originally Posted by cava

I like the way you think.

Hmmm, sometimes methinks Paul talks more bravely than truthfully. Knowing mrs. Bushmiller, I suspect he doesn't manage to get too much past her keen eye without its being noted. I think he might rely on tolerance rather than deceit.....

Apart from the problem of hiding the arrival of a lathe in your shed (you could start with a midi, which you just might be able to camouflage sufficiently to thwart a very casual inspection), they are horribly addictive things. Frustrating, at first, but once you get your first continuous shaving off a skew or bowl gouge, you're hooked and many find there is no return to normal life (and as far as I can tell, there is no available detox programme, either... ).

Originally Posted by IanW

Hmmm, sometimes methinks Paul talks more bravely than truthfully. Knowing mrs. Bushmiller, I suspect he doesn't manage to get too much past her keen eye without its being noted. I think he might rely on tolerance rather than deceit.....

I may be a little braver in theory than practice .

Regards
Paul

Ian
What are the overall dimensions of these clamps?

Originally Posted by justonething

Ian
What are the overall dimensions of these clamps?

Here's a very quick sketch with the main dimensions, jot: clamp dim.jpg

It's legible on my screen, so I hope you can see it ok (sorry, not a user of sketch-up or anything digital).

The info is for the 3/4" screws. You don't have to turn the screw & handle as one piece, it's quite feasible to glue a handle onto a piece of dowel. Make sure the dowel you use for threading is a neat but loose fit in a 3/4" hole. That allows for a bit of expanding & contracting with the annual moisture cycles.

The dimensions are flexible to suit your own needs, but the range I've given works well for me. If you go over about 200mm opening (i.e. having the screws any longer than about 350mm), it's too easy to bend & break them under load, but kept within the dimensions suggested, they are pretty tough. I've had some for at least 30 years that are still going strong.

Jaws need to be at least 38mm wide to accommodate the holes comfortably, but about 45 x 45 is what I aim for. You can make them wider if you like (good if you work with cedar or other soft woods). Just about any wood will do (even radiata takes internal threads ok) for jaws, but I prefer to use softer woods so that there is less chance of marring what I'm clamping up. I make jaws from suitable scraps & leftovers, which is why mine vary a bit in size & a lot in woods! I used a bunch of Camphor laurel scraps for the latest lot & it's excellent for the job, softish but threaded very cleanly. Hard woods are fine & will take threads well, I just prefer the softer wood for reason stated and because it keeps the overall weight to something comfortable. Remember the threaded holes are in one jaw only..

I've made larger clamps with 1" screws, these have 300-350mm long jaws and open to about 300mm or a bit more at a stretch. Also smaller ones with 1/2" screws. These are a bit delicate but great for small jobs. Again I've had some for more than 30 years, but any I loan out tend to come home busted - people will try & tighten them with the jaws way off parallel!

Cheers,

I was making a couple of sets of jaws for the last lot of screws I turned up, & took a couple of pics, knowing you are such a visual lot...

Something I didn't mention above is that it helps a lot if you have a suitable vise of some sort for your DP when drilling the holes in the jaws. Makes it so much easier to keep the holes aligned and square to the closing surfaces, which is important if you want them to go together neatly. I use this home-made thing, which I've been meaning to replace for the last 20 years! Jaws 1.jpg

Of course you could do it without a DP, and with a lot of care.

Here's a couple of jaws ready to go. The tapped jaw is on the left and the other jaw has a full size hole (i.e. 3/4" in this case) in the centre and a 5/8" hole (the nominal root diameter of the screw) at the top. The top hole in this jaw is about 20-25mm deep, just enough to retain the end of the screw when you are winding them open or closed: Jaws 2.jpg

And when I said you could use any soft-ish wood for the jaws, I was going to say "probably not Red Cedar". But then I thought, why not? Nothing like the old experiment to find out, thinks I, so I fished out some scraps and made two sets of jaws. One set is mature old wood and pretty firm for R.C., while the other is actually Kalantas and a bit less dense (& paler). The screws are Crows Ash: Cr Ash Cedar.jpg

Both pieces took a good clean thread, and I tested them by tightening them much more than I would in regular use. Both stood up to the presure-test just fine, so I'll let you know in 10 years time or so how durable they prove to be, but I suspect they are going to be just fine. They look pretty, too...

Cheers,