You might try a sptm, single profile thread mill...
A customer asked for some wood ovals with threads in the center. I made a couple dozen with a wood tap and didn't find it too hard. The size is 1/2" with 8 TPI and 1" depth.
Customer is on their second order of 120 pieces and frankly the manual method is getting to be a real pain. I could drill and tap the board while flat and then have the ovals cut out.
So, has anyone had success thread milling internal threads in hardwood?
The thread mills I have found online so far are quite expensive. Any tips on where to get them cheaper?
Also, the metal working thread mills are all different shanks. It would be great to get one with 1/4" shank.
Last edited by SteveS; 01-28-2012 at 06:43 PM. Reason: changed 6 tpi to 8 tpi
I just sent SCT an email with specifics of the job and asked for some advise. The SPTM did not have enough length (neck) at 1/2", but the carbide Threading Tools in their catalog seem to be good for my use. I'll post with my results.
If you need a thread mill, you can always braze a single 60 degree steel point onto a piece of 1/4 inch drill rod. The point only needs to stick out about 1/16 inch. Dress it up with a file. Put a little relief on the backside of the point for cleaner threads.
In wood, it should last a long time.
I didn't know about self-reversing tapping chuck option for a manual drill press, but after looking at the price ($200+) I would as soon walk away from the work. The volume and margin aren't enough to pay for the chuck in one or two orders and I wouldn't have any other need for it.
Thanks for the idea and it is something I might look into for another job.
Since you already have a wood tap, you could always power it with a small butterfly air wrench.
Lots of $29 adapters on Ebay.
Irwin Hanson 3095001 2 Piece Adjustable Tap Socket Set
If your tap has a 3/8 or 1/2 inch square on the end, these work very well.
Well, I already have one of those air wrenches so I will try it in the next week or so. Need to get an adapter, the tap has a round shank. Maybe a cheap chuck will work. My only concern would be be damaging the threads in the wood on the way out, but that is what a test is for. Actually after tapping in any manner with wood it is good to run a round wire brush through the tapped hole to clean wood burrs.
You might want to try a forming tap, which doesn't cut the wood. It might give you a much better hole.
Mach3 2010 Screenset
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)