Author Topic: Myford Super 7 Tailstock Micrometer Dial  (Read 803 times)

Offline Graham Meek

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Myford Super 7 Tailstock Micrometer Dial
« on: September 20, 2018, 10:43:59 AM »
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,

Offline Jasonb

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #1 on: September 20, 2018, 02:04:34 PM »
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.

Offline Graham Meek

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #2 on: September 20, 2018, 03:01:24 PM »
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,

Offline Graham Meek

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #3 on: September 23, 2018, 03:51:54 PM »
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,

Offline Don1966

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #4 on: September 23, 2018, 05:46:42 PM »
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

Offline Graham Meek

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #5 on: September 24, 2018, 06:22:39 PM »
Hi Don,

Thanks for the kind words of encouragement. I fitted a needle roller thrust race in exactly the same way to supplement the ball thrust race on my Maximat not long after it was delivered, (1986). The difference this makes when ejecting tailstock tooling is very noticeable. From this point of view the fitting of the thrust race alone is a worthwhile improvement.

My best regards
Gray,

Offline Graham Meek

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #6 on: September 26, 2018, 02:45:49 PM »
Has anyone any pictures of the Super 7 tailstock dismantled by any chance.

I am wondering if Myford had a short register for the bearing housing to locate in the tailstock body.

Also has anyone ever measured the "effective diameter" of the 1.375 x 20 TPI thread used on the bearing housing.

My best regards
Gray,

Offline Graham Meek

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #7 on: October 11, 2018, 01:06:39 PM »
Since the last post things have moved on a pace. Thanks to help and information from several forum members I have been able to make a start on the prototypes. The bearing pieces are finished machined and the dials require engraving, stamping, blacking and finally grind to reveal the scale.

The large ring in back ground is a gauge ring made to suit the thread dimensions.

I am indebted to John Slater who has produced some excellent 3D views of the assembly which I think might help to explain what is going on inside the dial.

My best regards
Gray,

Offline Xldevil

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #8 on: October 12, 2018, 12:28:46 PM »
Regarding your thoughts about a commercial version of this very great upgrade for Myfords,
I would ask the people of Hemingwaykits.
Maybe they have interest to make some kind of DIY kit available .

Offline Graham Meek

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Re: Myford Super 7 Tailstock Micrometer Dial
« Reply #9 on: October 13, 2018, 11:12:50 AM »
I must apologise for not getting back to you sooner, yesterday was not a good day.

I am reluctant to comment on the commercial side of this design, other than I am not connected in anyway with my designs that are on sale. I have always given my designs via articles for people to make their own versions. Increasingly today many would rather purchase these items ready made. I did for a number of years make the Handwheel Dial for the S7 for Neil Hemingway to sell and made over 500 in my time, but my health issues got in the way some years back. Given the success of the Handwheel dial for the S7 I see no reason to see why this new design will not follow suit.

My best regards
Gray,