A question arises "How precise do wooden threads need to be?" These are wooden Jogenson clamps?? ?Bill
On Tue, Jan 16, 2024 at 12:17?PM mike allen <
animal@...> wrote:
??? ??? Depending on the length of the thread & diameter of
the piece ya may be needin to use a Follower rest in the setup .
??? good luck , & remember pictures or it didn't happen
??? ??? animal
On 1/16/24 8:36 AM, Bruce J wrote:
On Jan 16, 2024, at 12:39 AM, DAVID WILLIAMS via
<d.i.williams@...>
wrote:
Dear All,
I realise this is both part Mini lathe and part wood
lathe. But to me the metal lathe part is more important.
Hence my question to you all.
I have a couple of these old wooden clamps - probably
antique. They are just like the metalwork ones we use, but
much much larger. One has a severely damaged (external)
threads.
I would like to try(?) and cut the replacement long wooden
thread on my 7 x 12. So, I bought a second hand thread
chaser on eBay. It¡¯s 6 TPI and according to the chart on
the Little Machine Shop site - the gear set up is no
problem on my imperial lathe.
[JFI it¡¯s Real Bull model purchased from Chester Machines
(in the UK) some 20+ years ago. If that¡¯s at all
relevant?]
You can chuck an appropriate dowel and single thread it to
start, but make sure what thread it is it might be some form
similar to an acme thread. You may well have to grind your own
threading tool.
You can use a chaser tool, (they used to be used for
cutting threads in metal, too) but be prepared to practice. In
metal they were also often used freehand ;ike on a wood
lathe.?
With the coarse thread, you may well be better off with a
hand crank on the lathe, too.
The thread chaser cuts multiple threads at the same time
and the tool (normally hand held I understand) needs to be
held at ~ 90 degrees to the thread, unlike the usual angle
for cutting one side of a metal thread. OR, if you are
doing it by hand, do you angle the thread chaser so it
cuts a series of slightly deeper threads. Thus the tool
needs to be held in the tool post at a similar angle?
I¡¯ll have to dig out my wood lathe books, but this article
on chasing threads pn a wood lathe indicates not.
Assuming I can sharpen it correctly and clamp
it to the tool post, can anyone offer any suggestions or
guidance? Do you cut it in multiple passes, in a similar
way to a metal thread?
I assume I¡¯m going to have to make and use some sort of a
travelling steady. My idea is to clamp it in the chuck and
use a small freely rotating chuck at the tailstock end.
I believe I can get a much better quality and accurate
thread using the gears than trying to use it hand held -
on a very long tool holder, the same as the ones on a wood
lathe. I have to check but I think the wood for the screws
is normally Beech, if that¡¯s relevant?
You want very hard wood Beech is one, or lignum vitae etc. the
article above lists some suitable species.
Thank you in anticipation.
David of Abingdon(UK)
--?
Bruce Johnson
"Wherever you go, there you are." B. Banzai,
PhD
