Thread: Wooden clamps

Good stuff, Ian. One of my first projects (after the other ten first projects) when I get my new shop up and running is to get a Bealle threader and make some of these, so having a bit of insight is great.

Hey Luke, while you are working through the first 10 first projects, you'll be able to pick up a few hand screws from Harbor Freight for under $10 to see you through.

Franklin

Originally Posted by Fuzzie

...... hand screws from Harbor Freight for under $10......

The 10 inch, which would be the equivalent of my woodies above, are just $8.99!! If I'd been able to buy them at an equivalent price 30 years ago, I probably never would've gotten into making wooden ones.

However, I'm glad I did, apart from being almost cost-free (retiree's time is cheap! ), they are nicer to use, imo. I made a few with metal screws before I had any wood-threading gear, they are quite easy to make using all-thread. Having a single thread direction on the bottom (compression) screw means they open & close at half the rate of the ones with L & R hand threads, but you can still work them pretty quickly. I've noticed at gatherings like the wood show that lots of folks don't know how to quickly spin them open & closed - I should put up a little video clip sometime (if I ever work out how to edit them).

For everyday work I prefer to use my woodies, they are capable of applying plenty enough pressure for all practical purposes & have a more friendly feel to them. The wooden screws are far less likely to mark an edge if they accidentally make contact, too. You might have noticed I used a couple of metal-screwed clamps to hold the threading jig on the router, because they are an odd size that just happens to suit this particular job.

One of the claimed advantages of the metal-screw clamps is that the jaws can be closed off-parallel. You certainly cannot do that with the woodies, it bends the compression screw and invariably breaks it. I have lost count of the number of times I've lent clamps with a stern warning to keep the jaws roughly parallel, & had one or two returned with a busted screw. There are very few situations in general cabinetry where you need to clamp work that is markedly non-parallel, and even fewer where the jaws will actually clamp the work without sliding off. On the rare occasions I have to clamp odd shapes, a couple of hastily-shaped caul-blocks usually does the trick. They may need to be taped to the work or the clamp jaws while you get them in place, unless you have a spare pair of hands available...

Cheers,

Gidday

What is the source of the threading gear you use Ian. I have been wanting to make some of these for a while now. I have a few metal variants made by an engineer friend and I find them super useful with metalwork but less so with woodwork.

Cheers
Bevan

Originally Posted by Enfield Guy

Gidday

What is the source of the threading gear you use Ian. I have been wanting to make some of these for a while now. I have a few metal variants made by an engineer friend and I find them super useful with metalwork but less so with woodwork.

Cheers
Bevan

Bevan, the tap in this particular case is a commercial 3/4", 6tpi tap that I bought cheaply about 30-something years ago. At the time, you could buy them on their own quite cheaply, but the threadboxes were quite expensive. These days, you don't seem to be able to get taps on their own, but Carbatec and others sell threadbox/tap sets that are relatively cheap. There are a few local woods that would respond to the traditional threadbox (although I haven't tried it, I reckon Crows ash would be one), but they can be finicky things to set up and won't work on our harder, siliceous woods, so I long ago switched to the router for cutting screws.

If you can pursuade a metal-working type to make a tap or two for you, you have to convince them to do a few things to make them work well. Apart from the very coarse pitch, you need LOTS of chip clearance, and negative rake works best on the cutting edges. You also need a good length of shaft of the minor diameter (in the case of a 3/4" thread, ~5/8") to act as a pilot & keep the tap running true. And they don't need to be hardened, all of my taps are soft enough to file, but have done the job perfectly well for many years.

I think we established that you live not far from me - drop over sometime and you can have a go with my gear to get the general idea. You could make enough threads in an afternoon to keep you going for quite a while, I reckon...

Thanks Ian.

I live on the northside but out your way is of no consequence to me. I will take you up on your magnanimous offer but that won't be until after the end of August as I am a little busy between now and then as can be seen in this thread.

The crazy things we do for fun, and charity.

You are a kind and generous man.

Cheers
Bevan

Originally Posted by IanW

One of the claimed advantages of the metal-screw clamps is that the jaws can be closed off-parallel. You certainly cannot do that with the woodies, it bends the compression screw and invariably breaks it. I have lost count of the number of times I've lent clamps with a stern warning to keep the jaws roughly parallel, & had one or two returned with a busted screw. There are very few situations in general cabinetry where you need to clamp work that is markedly non-parallel, and even fewer where the jaws will actually clamp the work without sliding off. On the rare occasions I have to clamp odd shapes, a couple of hastily-shaped caul-blocks usually does the trick. They may need to be taped to the work or the clamp jaws while you get them in place, unless you have a spare pair of hands available...

Cheers,

I wonder whether it would be worth trying to replicate the mechanism of a Jorgensen clamp by having the internal threads cut in inserts in the jaws which had pivoted ends. Obviously the jaws would need to be made in two halves which would be glued together capturing the pivotting threaded block and a clearance area would need to be cut out of the jaw pieces to accommodate the axial movement of the screws relative to the jaws. What I have in mind would be a bit like a Krenov-style plane with the screw running through the pivot pin.

I suppose that if you were going to go to these extremes, we should look at going the whole hog and using alternating left and right handed threads.

Now I really am over-thinking things!

Originally Posted by Enfield Guy

.... I will take you up on your magnanimous offer but that won't be until after the end of August as I am a little busy between now and then as can be seen in this thread...

No worries Bevan, it might have to wait a little longer than that as I'll be away most of August, then again in mid-September. But we'll get together eventually, just contact me when you have a spare afternoon....

Have fun tuk-tuking.....
Cheers,

Originally Posted by jmk89

.......I suppose that if you were going to go to these extremes, we should look at going the whole hog and using alternating left and right handed threads.....

Jeremy, there is absolutely no need for L & R hand threads with the woodies. The opposite-thread metal screws are usually based on 3/8" NC or Whitworth, which have a pitch of 16 tpi. With the left & right threads working together, that effectively halves the pitch, so you get the equivalent of 8tpi. The wooden threads I use are 6tpi, so they actually open & close faster.

Originally Posted by jmk89

.......Now I really am over-thinking things!..........

I think you are.
As I said, being able to close the jaws off-parallel is of dubious value. I live very happily with my 26 (now 34) pairs of parallel-closing hand-screws...

Cheers,

A new lathe has come to live with me, which prompted a flurry of turning (had to give it a decent test-drive ), & among other things, I turned up the remainder of the suitable blanks I'd put aside for possible clamp screws: Clamp screws.jpg

I don't think I will need to make another 3/4" clamp screw for the rest of my life, I think I've definitely got too many, now. Among this lot were a few woods that I'd long meant to try, because I suspected they'd be quite good for threading. These were Brush-box (now Lophostemon confertus, previously Tristania conferta), Tallow-wood (E. microcorys) and Jarrah. All threaded very nicely, though I only had one piece of Tallow wood, so that's not exactly a big sample size. I will need to use them for a while, too, to see how durable they are, before pronouncing them truly good, but I reckon they will stand up ok.

Messy business threading with the router - it sprays fine chips all over the shop! This window ledge is about a metre & a half from where the router was set up: 5 Chips.jpg

Cheers,

Ian

Let me know if you want some more Tallow wood to improve the representative sample. I have plenty.

Regards
Paul

Originally Posted by Bushmiller

Ian

Let me know if you want some more Tallow wood to improve the representative sample. I have plenty.

Regards
Paul

Thanks Paul. I should increase the sample size for a more 'scientific' study, I know, but I have an embarrassment of clamp screws right now so it will be a while before I'm likely to make more of those. If you've got a 3 x 3 by about 500 long, I wouldn't mind trying that for a bench screw some day.....

Cheers,

Ian they look brilliant love the timber range and colour. Just another thing on the todolist. If you feel you have to many I'd be happy to store some for you.

The male screw thread is one thing, but how do you go with the female screw thread of the nut, especially if it is of the larger sizes?