David , seeing that yer in the UK could the hand screw be
Whitworth ? I don't remember anything about thread differences from
Whitworth to
Standard .
animal
??? 1/28/24 11:30 PM, DAVID WILLIAMS via groups.io wrote:
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?Dear All,
My original one, (complete) is probably 150 years old, possibly more.
The broken one is probably the same vintage, albeit smaller. This is the one I would like to restore at some point. I have got quite a few clamps for woodworking but the working one has the longest reach.
The original thread(s) measures ~ 5/8¡± x ~ 6. Look at the detailed image.(You can see even the 6 TPI is not perfect.) JFI - Hence my scribble says ¡°Seems to be ~ 5/8 x 6 TPI. (I¡¯m sure you all understand but just in case the symbol for approximately is ~.)
I don¡¯t think anyone makes a 5/8 x 6 wood tap/die any more. Hence my request for assistance and using my 7 x 12 mini lathe. (Dare I mention the words after the recent discussion ?. ?) I was wondering if I could increase the thread to the more usual 3/4¡± x 6?
I think(?) the thread is made of beech.
I hope this is useful.
Thank you to all those who have offered help and assistance.?
PS As we all say, ¡°You never stop learning - Every day is a day at school!
Regards,
David (UK)
On 28 Jan 2024, at 20:03, mike allen <animal@...> wrote:
?like these ?
thanks
animal
On 1/28/24 12:01 PM, David Wiseman wrote:
They are of the style of an engineers hand clamp but really HUGE in comparison and of course made of wood.
Best regards
David
On 28 Jan 2024, at 19:01, mike allen <animal@...> wrote:
?Are these clamps the " hand screw " clamps ? They have left & right hand
threads . I've never seen a set with wooden screws .
animal
On 1/15/24 11:39 PM, DAVID WILLIAMS via groups.io 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?]
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?
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?
Thank you in anticipation.
David of Abingdon(UK)
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image1.jpeg: /g/7x12MiniLathe/attachment/118630/0
image2.jpeg: /g/7x12MiniLathe/attachment/118630/1
image3.jpeg: /g/7x12MiniLathe/attachment/118630/2
