Thread: It's always a good day...

What router bit are you using to form the threads on the screws? I would expect a VEE groove bit, perhaps with a small flat, but your screws look like they are almost rounded? perhaps it is just the way the light hits it in the photo.

Originally Posted by Kuffy

What router bit are you using to form the threads on the screws? I would expect a VEE groove bit, perhaps with a small flat, but your screws look like they are almost rounded? perhaps it is just the way the light hits it in the photo.

Kuffy, I see what you mean, the bottoms of the threads do look rounded, but they're made with a 60 degree V-bit, so I guess it's the light playing tricks. The tops of the threads are very heavily truncated, too, which might be adding to the illusion.

Actually, I wish I could get a bit that had a radiused tip, so the cuts didn't need to be so deep & the screws would match the tapped nuts better, but they just don't seem to be available...

Cheers,

You can certainly get vee bits with a small flat on the end. They are used for folding Alucobond composite sheeting. But I don't think they would be available at 60 degrees, just 90 and 135. Can't see why you couldn't just grind the tip off the end. The tip basically just drags through the material anyways because it has a near zero tip speed.

How does the blank get started travelling through in the correct manner, Ian?
Thanks,
Paul

I purchased a 3/4" Beall wooden tap & die thread cutter over 2 years ago. Its still in its original box unused. Had plans of making up some wooden clamps. That's still on the to do list.

https://www.youtube.com/watch?v=jLTEBUfzFFQ

Originally Posted by Kuffy

You can certainly get vee bits with a small flat on the end. They are used for folding Alucobond composite sheeting. But I don't think they would be available at 60 degrees, just 90 and 135. Can't see why you couldn't just grind the tip off the end. The tip basically just drags through the material anyways because it has a near zero tip speed.

I used a regular angled trim bit with a bearing. I removed the bearing and ground away the shaft that it was on and it works as a flat bottom V.

The Beall trade mark reminds me of my old mate Digs. We were demolishing a building at Whim Creek copper mine in the eighties. I think the building was pre fabbed in Germany about a 100 years previously and the nuts were not a good fit in the socket we were using on the rattle gun. Digs was hooking a stuck nut out of the socket when he inadvertently pulled the trigger and spun the nut up his finger. The only way to get it off was to hang on tightly to his hand and reverse the gun and spin it back off. Jeez we laughed, we told him that's what you get when you try to put a metric nut on an imperial finger.
Sorry about the hijack but couldn't resist when I saw that trade mark, thanks Stewie.

Originally Posted by pmcgee

How does the blank get started travelling through in the correct manner, Ian?

That's the only (slightly) tricky part, Paul.

You set the bit just in front of the first land of thread, so it will take out its profile. This is easy with large diameter threads because you can see everything clearly, but a bit more fiddly with smaller sizes. If the bit is too far forward or back, it will alter the pitch & your thread won't fit in the nut.

Once everything seems to be right, fire up the router & insert the dowel til you just feel the bit bite, then twist as you advance the dowel ever so slightly. The 'trick' is to just pretend you are screwing in an already-cut screw, if that makes sense. The groove slides onto the thread land & pulls the dowel in as you turn, which you should be able to do very easily with your fingers - if you can't turn it easily, something is wrong, either the bit isn't deep enough, or is in the wrong place. It takes a few false starts the first time you try, but after a while you get the hang of it and I can usually start first go. If you mangle the start, as I sometimes do when not paying proper attention, just back out, whittle off the crook bit, and try again.

Cheers,

Originally Posted by Bohdan

I used a regular angled trim bit with a bearing. I removed the bearing and ground away the shaft that it was on and it works as a flat bottom V.

That's a good idea, Bohdan - I've ground my own bits from old 1/4" HSS twist drills, which work well enough, but dull pretty quickly in siliceous woods and need frequent touch-ups, which is the main reason I went to the solid carbide bit. Hadn't thought of trying to shape a trim bit.

Kuffy, I would've tried rounding my bit, but I am hesitant to do that because it has a pair of 'wings' on the tip of each flat, which seems like overkill, but I think they do help to cut very clean edges on the groove. I worry that I'll make a mess of these. I do have a well-worn bit that I could experiment on, when I get myself a wheel that I can shape carbide on.....

Stewie, let us know how you get on with your Beall kit when you get that round Tuit. I think they make them so it's a little easier to align the bit than with my home-made jigs. Worth watching that video, if you're planning to do this, it shows you how quickly & easily the thread is cut, so if your dowel doesn't feed in easily like that, you know something isn't right. I'm looking for a round tuit to make a short video on threading a bench-screw, to go with part II of the article in AWR, with luck, it'll be up before the next issue comes out.

I made a handle like the one in the video, early on, but found it was not all that useful & almost never use it. For starters, I like to turn my handscrew blanks as a single piece, rather than faff about glueing a handle on later. In any case I didn't find it any easier than screwing the dowel in with my fingers, & I get a better 'feel' of how it's all going. Try to keep the blank moving evenly, to avoid little wobble or burn marks, they won't affect function, but they look unsightly...

I'd hoped to be able to show you a set of clamps all done & ready to oil, but had a few interruptions today, and it took a while to mill up the odds & sods of scraps for the jaws, so not quite finished, but it won't take long to fit the last two pairs in the morning. Clamps.jpg

I've been trying out some new woods both for jaws & screws lately. One new wood I used for screws is Celtis, or Chinese Elm. It has a bad reputation as a difficult wood that likes to twist & buckle and doesn't even make good firewood, but it turns nicely & took a very nice thread. It seems tough enough, so I'm hoping it will go the distance. Most of the jaws are Camphor or Silky oak, cos I had lots of scraps of them,& I like to use softish wood for jaws...

Cheers,

Lots of interruptions over the last few days, visiting children (& their children!) and long lunches, so shed-time was limited & snatched between socialising times.

The steps remaining from the point at which the last post ended were to strip them down, plane a small chamfer on the exposed edges of the jaws, then oil all the bits: Oiled.jpg

When the oil was good & dry, everything, especially the screw threads, got a thorough waxing (not only to promote smooth action, but to prevent disasters from any drops of glue that might find their way into the jaw threads! ). And here they are ready for use: All done.jpg

I now have handscrews in 4 sizes, from 300mm, 1" screw monsters to little 1/2" screw things: All sizes.jpg

This is more than anyone needs, of course, but I can't help myself, I get caught by my curiosity about how different woods will thread. The bigger problem atm, though, is to find enough room for 7 more clamps in my shed with its limited wall-space: Wall of clamps.jpg

I guess it's a problem many wouldn't mind having.....

Cheers,

That's a really enviable collection of wooden clamps.

I suspect that some less charitable souls might point to the dawning of an obsession, but I can see the scientist in you coming to the fore with the desire to examine all possibilities with clamp making. I understand .

Regards
Paul

Yes, Paul, it's purely for the pursuit of knowledge......

Cheers,