Supporting > Tooling & Machines
Myford Super 7 Tailstock Micrometer Dial
Graham Meek:
Hello All,
It has been a while since I last posted, and my apologies for that.
Following a request from a Forum member I have been working on the design for a micrometer dial for the Myford Super 7 Tailstock handwheel.
George Thomas came up with an elegant design some years back. While it was graduated 0 to 0.3" and gave 0.001" per division using this in conjunction with the barrel markings in eighths would not have been easy. Easier if the barrel had been graduated in tenths of an inch. Of course it did nothing to help those with a metric lathe.
I have worked out two designs and the schematic is shown below. A metric version graduated 0-10 mm per rev has an error of reading plus by 0.000127 mm per rev. The imperial version is graduated 0-0.500" and has no error. This is always assuming a true theoretical pitch of 0.300" on the tailstock feedscrew.
Both dials have a friction Zero setting as used on my Apron handwheel design. I have also added an oilite bearing to reduce the need for constant oiling as well as a Needle thrust race to compensate for the reduced Handwheel boss diameter when ejecting drill chucks , centres, etc.
As yet I have not detailed all the parts, but I have had the maths checked as regards the gear ratios.
My best regards
Gray,
Jasonb:
That's quite a steep pitch screw on the Myford, never knew they were that coarse is it multi start? I'll stick with my Far Easten machine with it's 10tpi tailstock screw and 100div handwheel.
Graham Meek:
Hi Jason,
The Myford tailstock thread is a 3-start thread, the thread form is Acme but follows the proportions of a 10 TPI thread form. I know that sounds like a contradiction but I could not see any other way to describe it. This does give a very sensitive feel when drilling with small drills. From what I remember that is, as I have not owned one for a thirty plus years. My Maximat Super 11 came with a 2 mm pitch thread and is fitted with a dial as standard. This is a good compromise as far as I am concerned.
My best regards
Gray,
Graham Meek:
Just to let those of you who may be interested in this design know, I am writing an article on these dials. As regards when and which of my usual magazines will publish first I cannot say. A lot will depend on how soon I finish the prototypes.
I have also been asked if these dials will be available commercially?
Whether the ME suppliers will manufacture this dial alongside the Handwheel Dial for the same lathe I do not know. I express the usual caveat about no financial involvement in this. No doubt if there is a requirement for the dials the need will be met.
My best regards
Gray,
Don1966:
Interesting design Gray I did make one for mine years ago from George Thomas design and had started the carriage micro dial but have never completed it as of yet. Love the addition of the bearings in your design.
Don
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