Imperial pitches on metric Myford 254

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Imperial pitches on metric Myford 254

This topic has 11 replies, 5 voices, and was last updated 29 March 2019 at 09:57 by Howard Lewis.

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27 March 2019 at 23:23 #402465
lfoggy
Participant
@lfoggy
I want to cut some inch pitches on my metric Myford 254Plus. The manual contains a description of how this can be achieved. You need a gear train with a 48, 60, 63 and 64 tooth gear for all imperial pitches and then 24, 27, 33, 36, 39, 42, and 57 on the input shaft to get the full range of pitches from 4 to 56 tpi.. These are all unusual gear sizes (apart from the 60 which I have) and I am having trouble sourcing them. When I purchased my lathe in 1997 they were offered as an option by Myford but foolishly I did not buy them at the time. I've worked out that substituting a 127 gear for the 60 gear on the input shaft will enable some inch pitches to be cut by selecting differnt gearbox settings – that may be my only option.

Any idea where I can get these gears or any other options?

Edited By lfoggy on 27/03/2019 23:28:30
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27 March 2019 at 23:23 #13471
lfoggy
Participant
@lfoggy
28 March 2019 at 06:59 #402474
JasonB
Moderator
@jasonb
Myford list the 24, 27, 36, 39, 57, 63 and 64 for an easy start.

42T on Home and Workshop

Maybe some here

If all else fails Boston Gear do change gears of correct DP and pa, should be able to get those via one of their distributors.

Page 28 of catalogue

Edited By JasonB on 28/03/2019 07:38:42
28 March 2019 at 07:42 #402475
lfoggy
Participant
@lfoggy
Myford do list some of these gears on their website but when you try and order them you find many are not actually available…..
28 March 2019 at 07:53 #402476
JasonB
Moderator
@jasonb
I thought they tended to take them off the list when OS, certainly let me go through to checkout before I bailed out.

Certainly worth ordering what they have and then search out the rest. They do get new stocks in from time to time though may well be steel gears now rather than cast.

May be more on Home & Workshop as I only looked for the ones not listed on Myford.

Edited By JasonB on 28/03/2019 07:55:05
28 March 2019 at 13:37 #402535
Bazyle
Participant
@bazyle
There might be a simpler alternative with more conventional gear values. If you can get one set up that gives you an imperial thread, preferably multiple of 8tpi, and only using two gears and some idlers. Then you can modify it with a standard set of gears in steps of 5. You would end up with an extra stage or two so probably need an extension to the banjo.
28 March 2019 at 14:01 #402540
Brian G
Participant
@briang
Before looking for additional gears, try downloading NThreadsP or BoxfthreadP from http://www.lathes.co.uk and putting in the gears you have. Depending on the pitches and accuracy you need, it might be possible with the gears you already have. I spent a while yesterday looking at the ratios for my son's Chester and found that as well as the pitches listed on the machine's table he can cut 14, 26 and 60 tpi within 0.05% using the existing gears (without a 63 or 127 tooth gear) – result!

Brian
28 March 2019 at 19:22 #402586
lfoggy
Participant
@lfoggy
Thanks everyone. The link JasonB sent me (thanks) to Triona ltd was helpful. They have almost all the gears I need apart from the elusive 48 tooth that nobody seems to have ! Without that one I can't use the Myford recommended arrangement. As Bazyle says, there must be a simpler aleternative and I am looking at the links sent by Brian G. Will get there in the end.
28 March 2019 at 19:30 #402588
JasonB
Moderator
@jasonb
Have you thought of cutting your own 48T

Edited By JasonB on 28/03/2019 19:47:05
28 March 2019 at 19:44 #402590
JasonB
Moderator
@jasonb
Or what about something like this which is the right p.a. and just modify the hole, cheaper than Myford too.
28 March 2019 at 20:55 #402604
lfoggy
Participant
@lfoggy
Many thanks for this link JasonB. That just might be the solution. Cutting my own 48t gear is also a good idea. Would be an excuse to play with the new Vertex indexing head I recently bought.
29 March 2019 at 09:57 #402658
Howard Lewis
Participant
@howardlewis46836
Go for it!

If you have a Vertex HV6 with a 90:1 ratio, for 48 divisions, you use the the 16 hole circle on the A plate.

Index 1 turn and 14 holes on the 16 hole circle, for each division.

Howard.
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