Thread cutting

[BOB A JOB]

Hello,

Has anyone tried using engineering Taps & Dies on wood, I'm interested in having a go at the larger sizes in probably BSW as it has a coarser ? (more coarse?) thread.

Iv'e seen std thread chasers demonstrated, and the thread cutting tool from the likes of Axminster but, I wondered if engineering tools would work.

I assume that timber selection would be important, close grain - Box etc ?

Regards,

Bob 

[woodndesign]

Hi Bob, you've summed it up about right, Box or any close grain would work fine, As with the use of taps & dies, I've tapped Elm even with 8mm for a gearknob as a long thread which has been fine, but at best some CA Glue would reinforce any thread, then re-tap to tidy.

You can thread timber for direct fit to the lathe for jam chucks/glue blocks as well. Opens a whole realm of usages.

For chasing look up John Berkeley ... http://www.johnberkeley.biz/ .. this I found as an easy tool to master and joy to use. And cost efficient even with adding the rest of the tools, the one is your lathe has a speed about 350 rpm or less.

Cheers  David

[Dave Atkinson]

Hi Bob

I use 3/16 Whitworth engineering die to get a 24 TPI thread.

Other useful sizes are:

•   3/8 inch Whitworth – 16tpi thread
•   5/16 inch Whitworth – 18tpi thread
•   1/4 inch Whitworth – 20tpi thread
 
Any timber that will take a hand chased thread will take one of the too.  Apply a little wax to the tap or die first thought.

Suitable timbers include Box, Leadwood, Cocbolo. pink ivory, African blackwood and most anything else that is close grained.  Labuenum and many of the fruit woods also take a thread.

Cheers Dave,

[MCB]

I  have some large Whitworth taps that I  suspect I'll  never use, so if you are interested, I  suggest that you contact me OFF LIST with your  telephone number. I'm located in Hertfordshire.

MC

[Eric Harvey]

they work ok on plywood have used them for making jigs

[Bryan Milham]

Bob,

as luck would have it, if you buy this months Woodturning magazine, Kurt Hertzog goes through all the options for cutting threads in timber, from hand chasing, taps & dies, inserts and machines to cut them on the lathe.

And yes, I use taps and dies to cut threads, up to M33 x 3.5mm to suit my headstock.

[BOB A JOB]

Just got the magazine thanks, only the second time I've bought one, last month they  gave away a great book on Spindle Turning - £16.99's worth. 

Some of the guys in our club were a bit miffed as they didn't get the book - they are on subscription ! 

Regards,

Bob

[The Bowler Hatted Turner]

hello Bob,
              I wanted to reply to this post but for some reason I was unable to sign in. (of course it can't be anything I have done wrong it must be the computer!! :-[0
Anyway, yes you can cut a thread with engineering chasers. I have some of them and they work very well. there are lots of bits and pieces out there about thread chasing and I have probably read it all in my efforts to learn, which I am glad to say I did.
 Thread chasing is a funny thing, you either have the touch or you don't, persevere with it, it will happen.
One of the funny things is I can chase a thread on the Graduate at 425 rpm but when I try to do the same on my Ax. 330 I can't because it goes at 430 rpm. Now not everyone will have the same problem, some woods you are better off slowing down to thread. some woods will not take a thread of a certain size but will do nicely if you change the thread tpi. I admit to not using a cutting compound but like Dave I add a bit of wax just to smooth the cutting.
   When I tap a thread in wood I always try to cramp a band around to prevent splitting, ie on a handle for a wand. Or I cramp it with the chuck jaws.
   Depending on the wood and the purpose thereof I will coat the threads, in and out with super glue just to help prevent breakout when in use. I will sometimes thread a joint and glue it just for a bit of extra strength.
 Now reading your comments again I see I have missed the mark somewhat so in reply I have also used taps and dies to thread wood. Tapping the male thread can be a bit hit and miss as they tend to chew the wood up a bit.
Hope this is of some use.
Regards
John BHT
John Berkeley's book is very good.

[bodrighywood]

I have tried this several times and failed. I really would like to get the hang of it a
s I have a number of things I make that would benefit but I am not willing to fork out the cost of the cutters just to experiment. Maybe something for a hands on night at the club?

Pete

[julcle]

I borrowed a couple of 18tpi chasers from the club after a hands on night and had a bit of practice with some black wood over the Christmas period. Although the chasing bit inside or out can be picked up quite quickly I find that getting the diameter of the two surfaces parallel and true extremely difficult. Maybe another spend in April on the club outing to Martock is in order  --  Julian

[The Bowler Hatted Turner]

Julian,
         I always cut the female thread first as I find that is the harder of the 2 to do.  Measure the diameter of the finished female thread and add twice the depth of the finished thread, on completing the thread you may have to take a little bit more away but because the thread is already there it will be easy to do. I don't bother splashing out on expensive tools if I don't have to!!
Pete that could be a good night at the club I will suggest it at the next committee meeting.
Regards
John
BHT

[MCB]

.......... this months Woodturning magazine, Kurt Hertzog goes through all the options for cutting threads in timber, from hand chasing, taps & dies, inserts and machines to cut them on the lathe.

Would somebody like to summarise this article, please?

MC