Wood threads...

Re: Wood threads...

Ellis Walentine

>The metal lathe approach will not work too well on wood because the cutter is a scraping tool. Ideally, you want to shear the grain. You can make your own thread-cutting box -- essentially a box with holes in both ends and a v-grooving cutter attached next to the exit hole. I don't know of any published plans for such a box, but maybe someone here has more information on this method. I'm not sure how you would cut the inside threads, though, without a big tap.

The Beall system uses a v-grooving router bit perpendicular to the rod, which produces a nice, accurate cut. It would probably be the best way for you to approach this project, since you can also buy the big taps that you need to go with the thread-cutting setup.

Ellis

Re: Wood threads... *LINK*

Sandor in Boyds, MD

>I did exactly what you are suggesting here at work as practice for my eventual workbench.

Ellis is correct in his assertion about the cutter profile. I made a special cutter (will post pics whe I get home tonight) out of 1/2" aluminum square stock and an old bandsaw blade.

I bent the blade first to a vee, then made the sides parallel. I drilled two holes per side and mounted it to the aluminum bar. So I ended up with a kind of Vee pointed mini scorp.

I filed and honed the inside edge (incannal) of the blade and was very successful at turing 3 TPI threads on 2" OD hard maple, taking .025" cuts per pass.

I'm thinking I'll be making a tap similar to the one shown on the ilovewood website. They have a whole section on wooden threadmaking. Its pretty fascinating.

Sandor (who can't seem to work on only one project at a time...)


http://www.ilovewood.com

Re: Wood threads...

Adam Cherubini, NJ

>Mark,

I went the Chinese wood tap route. The taps and dies are decent quality. I did nothing to them. The largest available is 1-1/2" 6tpi. I find that thread too fine. That said, I use two such screws and they've held up reasonably well for several years. One screw slips alittle in one spot. I try not to over torque stuff, and all has been well.

You can try turning your own threads freehand. There are a couple books out on the subject.

Pretty sure the beall pitches are no better (coarser) than the chinese sets.

Last option is buying ready made screws. There's a guy in New York who makes them for under $100 USD (last I looked). (Crystal Creek Mill Works)

Not that you asked, but my advice would be either:

a) make screws with the cheap chinese taps, provided you have a wood lathe and know how to use it. If they go bad, you can always make new.

or

b) buy them ready made from a shop like Crystal Creek (NY)

Mark, you could spend way too much time learning to make screws, procuring the specialized equipment, and developing the skills to make them. There are so many other things to do.

But if you decide to invest the time, try to make taps and dies, 2" min, 3tpi and sell them to the rest of us! I would pay several hundred dollars for a newly made fully functioning tap and die.

Adam

Re: Wood threads... *LINK*

Clay Craig in Miami

>I did find this book which may help - never seen it 'in the flesh,' but it might steer you to what you need ...

Clay


wooden thread book

Don't buy one Mark, borrow mine

Andrew F in Australia

>Mark,

I have one of the Chinese ones 1.5", 6tpi - I used it to put a thread onto three screws for a bench - one more to go.

It works fine - just slipped a bit in the early stages and I learnt the hard way about resharpening the v-cutter ($18- replacement)

Looking at the threads right now, actually.

I used Qld silver ash for the threads - nice fine grain and holds the thread well.

Cheers,

Andrew

(you've got the number already)

Re: Wood threads...

Michael Kieta-Ramstein, Germany

>Saint Roy Underhill describes how to make a tap and die for workbench screws in The Woodwrights Work Book. The tap is wooden, guided by a spiral saw cut, and the cutter scrapes the thread gradually by repeatedly advancing the cutter tapping the "nut." I've always been interested in trying it, but...

Michael (who has some time now that wrestling season is finished!)

Re: Wood threads...

Doug Rice

>I am also interested in making screws for a bench plane, so I bought this book sight unseen. Don't bother. It has almost nothing about taps and dies, except to say go buy a set if you want one. It gives superficial reviews of the lathe accessories for cutting threads on lidded boxes, etc. Very little useful information. A big disappointment.

Re: Wood threads...

Alan Hamilton

>Mark,

What Michael said. Saint Roy of Underhill's book has the instructions to make your own screw box and tap.

Making a screw box shouldn't be too difficult for a wood worker. Making the tap, however, requires skills and tools not all wood workers have. Saint Roy uses a foundry and many of the sundry tools of a blacksmith. Making a small forge isn't all that difficult; but all the tools might be hard to come by.

I wonder if you could buy the tap somewhere and make a matching screw box yourself.

Alan

Re: Wood threads...

paul womack

>I think you'd want to hand-turn the mandrel, with a small router and a 'V' cutter on the tool post.

BugBear

Pic of wood threadcutting tool

Sandor

>Here is a pic of the threadcutting tool that I made to turn 2" bench vise screws. The largest threadbox I could find was 1.5", but I wanted something more beefy.

The cutter is a bandsaw blade bent to a Vee and mounted to an aluminum bar that fits in the lathe toolrest. I sharpened the blade in-cannal with a Dremel and slip stones.

At a slow cutting speed (with 3tpi the lathe bed really moves fast) and .025" depths of cut per pass, I was able to make a pretty nice screw out of 2" diameter hard maple.

I'm thinking I will make the nuts with a single point cutter embedded into the end of the threaded screw. www.ilovewood.com is down. Bummer. They showed a really clever way to cut the threads. YOu make a fake nut block using several pointed dowels to engage the already cut screw threads. this nut block is temporarily fastened or clamped to the real nut for tapping. YOu turn the screw and voila! you cut the matching threads. Easier said than done.

So yes, I suppose the answer to the original poster is yes it can be done....

Sandor (just finishing up the drywall in my new basement shop)

Re: websites

Mitchell

>does anybody know whether Crystal Creek Millworks has a webpage? I have tried looking in vain. Or if not, how does one contact them to see their wares?

www.ilovewood.com is back up

Pam Niedermayer - Austin, TX

>

Re: Wood threads...

Greg B�tit, Vergennes, VT

>This book describes yet another method of thread making, hand thread chasing done on the lathe. You must have a lathe that will run really *slow*. The internal threads are done the same way, so this would only work on workpieces that you can chuck up on the lathe (Perhaps not practical for a bench vise screw). I don't have the book, but I bought a set of tools similar to the one pictured on the cover of the book. They came with a video that shows you this method pretty nicely, but haven't tried it yet because I found out that I need to buy another motor and a variable frequency drive to get my lathe to run that slow.

Funny I bought the tools on impulse but am reluctant to take the $300 plunge to upgrade my lathe.

Greg -who probably should offer up the boxed set and video on the benefit auction forum.

still down just now ... ?

Clay Craig in Miami

>

Re: still down just now ... ? *LINK*

Pam Niedermayer - Austin, TX

>Try this.


Alburnam's Archive

The Workbench Book

Sandor in Boyds, MD

>Actually the method I was refering to previously for tapping the nut can be found in Scott Landis' The Workbench Book on pgs 122-123.

Re: Wood threads...

Mark Harrison -- in Sydney, Australia

>Adam,

Thank you for your thoughts. Yes, there are other productive activities I could be pursuing. I will probably take up Andrew's offer and try the Chinese versions.

I also like the look of the tool that Sandor made. That is an extremely nice looking piece of thread that he turned up. The trick will still be to create the nut!! That is the age old problem.

Thinking out loud, if the size of the male threaded component is sufficiently large, it might not be that difficult to make the nut in the same fashion because you have created enough room to get a larger tool in there. Hmmmmmm. Perhaps a 3" or 3 1/2" thread! That ought to have enough meat to it!!!!! My colleague's lathe is sufficiently low geared and large enough for this. Just need to make the cutter...

Thanks again,

Mark

Re: Pic of wood threadcutting tool

Mark Harrison -- in Sydney, Australia

>Sandor,

I presume that you annealed the band saw blade before bending and re-hardening?

That's a nice piece of work and has given me some other ideas (see my response to Adam above).

Thanks, I would NEVER have thought this idea up. That's what I love about this place.

Thanks,

Mark