Thread: Wood screwcutter

A set of these German ones would be nice.

Wood Thread Cutting Tool

I used a German made 62 mm for my threads , borrowed the tools of a friend , it was a spectacular thing to watch it cut the male thread. I don't know if it was the same make , but like these ones the 62 mm had two handles and two cutters that were set at different depths.

Rob

Originally Posted by auscab

A set of these German ones would be nice.

Nice but at $1400 for the 62mm and just over $1200 for the 50mm
I reckon some of our metal workers could make some big wood threading tools for a lot less...hmmm. Oh Brett...I've got a project for you

Mark, imo, 4 or even 3 tpi is a better pitch for wooden screws in the diameters you are talking about. Coarser threads are the go for wood as they are stronger, and saves some of the tedium of winding them back & forth.

The trouble with outlaying a bundle on a tap & die set is that you'll only use it a couple of times in your life, so unless you plan on leasing it out, it's not a very good return on the investment. I also think that the type of die Auscab is pointing to limits your choice of wood for screws. The traditional thread-boxes do a good job on the Northern Hemisphere woods, and some of our less recalcitrant species, but the couple I've tried choke on the tough stuff. Many of the bone-hard woods we have will take a beautiful, durable, thread, but you would be struggling to cut them with a V-tool thread-box, I reckon.

It's not that hard to make a thread-box for a router, and with a carbide bit, there are few woods you can't tackle & produce a nice thread on. I've previously shown my setup here.

Whatever method you opt for to make external threads, you still need some sort of tap. You can chase internal threads on a lathe, but it's not practical for many applications, so using a tap is the better solution. Unfortunately, these are next to impossible to buy on their own. The best solution is to make one. If you have access to a metal lathe & know how to drive it, easy-peasy, but a machine shop may be prepared to make one for a price that isn't unrreasonable. Taps for wood don't have to be tool steel - my 2" 4tpi behemoth is just mild steel & has already tapped more thread than most are likely to do in a lifetime.

However, there are several ways to skin this particular feline. My first large tap was my own 'invention'. It was a more or less 'conventional' tap made of wood, but with steel cutters (shown in the thread linked to above). It worked quite well on woods like Maple & Cherry & Beech (I was living in Canada at the time), but I havn't yet tried it in a chunk of Ironbark. It would probably thread Vic Ash quite ok, though, and that would make a perfectly good nut. Haven't used it in years because a friend made me some beautiful large steel taps, which will handle anything I've ever thrown at them, though it takes two people & a 600mm steel bar to turn the 2" tap into very hard woods....

The lowest-tech way of tapping wood that I know of was shown in an old Fine Woodworking mag, many years ago. The tap consisted of a long dowel turned to the minor diameter of the screw, You then saw a spiral kerf along it, matching the pitch of your intended thread. The kerf only needs to be about 4 or 5mm deep, enough to engage a metal plate held in a purpose-made 'nut' that can be clamped over the hole to be threaded. As you turn the dowel, it advances at the desired thread pitch The cutter is held in the end of the dowel by a wedge. You start with a shallow cut, and advance the cutter by increments as you repeatedly screw the dowel through the nut until you get the thread to full depth. I've always meant to try this method, but never gotten round to it because it's obviously a bit tedious compared with cutting the thread in a single pass as you do with a regular tap. Someday, I will definitely give it a try, and make up a tutorial (if I can maake it work for me!), because it's probably most appropriate way for anyone who just wants to make a couple of bench screws. You would still need access to a wood lathe, but that's pretty easy these days, and in any case, you need to make the blanks for threading, and although you could make them by other methods, of course, a lathe is the easier choice.

Cheers,

Thanks for the replies,
I'll probably go with the carba-tec as its $80 for the 1 1/2" kit I suppose it should be adequate. I wanted to make 2 bench vises and a tail vice, then later use it for a cider press.
Using local Tas hardwood with a straight grain should be ok?
Thanks again for the help.
Mark

Maybe in the woodturning section? sounds like a job for a lathe Phil

Originally Posted by msrampant

Thanks for the replies,
I'll probably go with the carba-tec as its $80 for the 1 1/2" kit I suppose it should be adequate. I wanted to make 2 bench vises and a tail vice, then later use it for a cider press.
Using local Tas hardwood with a straight grain should be ok?
Thanks again for the help.
Mark

Mark - 1.5" is ok for small bench vises, but 2" seems better for larger ones. Come to thinkl of it, I can't give you a logical reason for saying that - it's just a proportion thing, & I don't think it would make any difference mechanically. Only gripe I have with the Carbatec kit is it's 6 tpi, I think, which to my mind is a bit fine. You get tired of cranking tail vises in & out, and a coarser thread saves many turns over the years.....

If you want to use a Taswegian hardwood, you couldn't do better than Blackwood, I reckon - it should be excellent for threading. Haven't used it as fr as I can remembeer, but have threaded some local Acacias with very similar wood properties & they were good.

Cheers,

Thanks for the heads up on blackwood, I have enough for the three vises.
$80 for the 1 1/2" is better than 1200 for 2" that's out of my range.
Cheers,
Mark

Here's a link to a router based version in the US that has good reviews:
The Beall Tool Company

Hi Mark,
I'm sure, if you go back through all the Threads, you will find there have been a few of these Home Made, & I don't think it was all that hard
Something like, Buy a Nut or 2. put the Hacksaw Blade through the Nut, & I think you make 4 Cuts, or maybe it is that you make 3 Cuts & the 4th. Cuts through the Nut. Not real sure, now, but I know they are there.

Originally Posted by hiroller

Here's a link to a router based version in the US that has good reviews:
The Beall Tool Company

I second this recommendation. I have used one of these (unfortunately don't own one or I'd lend it to you) and have had perfect results every time - no messing, no fussing. If you have a router - trim or standard, all you'll need is a 1/4" collet or sleeve and you'll be good to go.

mark.....I am in the process of making my own hand cranked - router thread cutter. Effectively working like a mini lathe, I am producing a cutter bed that reduces the 10-11 threads on a 3/4 inch bar down to about 3 threads on the proposed finished stock. Here are some pics ...this may be of interest to you ...but what it does is hopefully give me a prototype for cutting a few timber threads on which I can base another version that will allow me to choose and replace the gears thus allowing me to manipulate the ratios and produce threads with different gears per inch...etc. (or the metric equivalent). here is a quick snapshot of the lathe as its progressing...ps...its primarily built in timber.....IMAG0639.jpgIMAG0640.jpg

Wow , Nice one szczepan4069 , please keep us informed of your progress.

Rob

rob, will get another thread happening to cover this wood thread lathe.....shortly....