Graham Meek?s Tailstock Dial - MEW279

I’ve just been reading the first part of the article in MEW 279 describing Graham Meek’s tailstock dial for the Myford S7, and noticed some obvious errors and omissions in the details of the gear cutters (figures 4 and 5). In figure 4 the r1.38 dimension for the 48 tooth cutter cannot be correct. In figure 5 the r1.5 dimension for the 54 tooth cutter is also clearly wrong. In all cases no dimension is specified for the cutter widths.

To deal with the last point first, the drawing for "Typical cutter Profile" has yet to be published.

You are right in that the dimensions are wrong.

In the case of the 48 tooth gear the numbers have had an Eric Morecombe moment. "all the right notes not necessarily in the right order". The same with the numbers, they are all there, but not in the right order. The view of what I sent in is below.

The 54 tooth gear is however way off, again below is the drawing submitted with the article.

These radii are the flank radii of the actual tooth profile. The radii will be different if you try and use Ivan Laws tables based on the Browne and Sharp system. Where each cutter profile in the series is made to the smallest number of teeth to be cut by that cutter.

My cutters are the closest one can get to an Involute form, using a form cutter. Without resorting to a hobbing machine. This gives a much smoother action between the gears.

Regards

Gray,

Thanks Gray

i was pretty sure that your original data would have been spot on.

Looking forward to the second article, and making my own version of the dial.

Regards

Mike

Oh dear, sorry Graham.

Not sure what happened there as usually we don't actually edit the numbers. I suspect they had to be retyped when changing the lines to arrows.

My rough count is that there are 68 dimensions in that article so the only excuse is that it is impractical to check them all back against the original drawing; because they normally don't get retyped resetting doesn't normally introduce mistakes and we normally just look out for any obvious errors.

I'll put a correction in the next installment.

Neil

Hi Neil,

No problem this end, as you know I make mistakes too.

Regards

Gray,

Posted by Graham Meek on 28/03/2019 10:28:39:

In the case of the 48 tooth gear the numbers have had an Eric Morecombe moment. "all the right notes not necessarily in the right order". The same with the numbers, they are all there, but not in the right order.

Where is "Mr Preview" when you need him..... ...I'll get me coat.

Steve.

Good to see you back on here Graham. Hope all is well with you. I'll be following along with the boring head postings!

Yes Graham, also glad to see you back!!

Best wishes,

Tony

Ditto.

Thank you all for your kind regards,

Gray,

I am looking forward to the second installment and plan to make the dial for my metric Myford 254plus.....

Gray

is there a version for the Boxford AUD either in existence or planned please?

regards Ian

Hi Ian,

I have no plans at the moment to design a dial to fit the Boxford lathe. The last time I worked one of the machines was in the Grammar School workshop, circa 1966. If my memory serves me correctly the feedscrew thread is a single start thread. If this is so, then the dial would be a simple affair, not requiring any gearing. Unless of course the feedscrew uses a non-standard pitch, it has been known in the past.

Regards

Gray,

This sounds like yet another instance of ME/MEW taking contributors drawings, redrawing them and getting them wrong. Previous editors (not the present incumbents) have denied that they redraw anything, plainly not correct. Why not just publish what is sent in, then if it's wrong they can blame the contributor. Even I can convert a dwg to a jpg, which can then be treated just like a photo.

Hello All.

Has anyone attempted to make one of these yet?

Can anyone offer any advice?

Thanks,

Brian

Hi Duncan,

There are a number of issues, chief of which is we need to be able to manipulate line weights and font sizes to suit the size at which the image is published, or move components around to fit the layout. Clearly there's no way way a contributor can anticipate these. very often drawings are provided as a single sheet that has to be split up.

Also, the standard of drawings varies hugely, not everyone is as experience a draughtsman as Graham!

DWGs are (in my experience) incredibly prone to losing lines or changing details on export; I have no idea how industry copes. A DWG done in one package isn't always even openable let alone accurate opened in another package (I got a DWG or DXF a couple of days ago that wouldn't open properly in either Alibre or Turbocad).

If converted to a jpeg we can't do anything to edit them, and they can lose definition and are almost impossible to change if there are any shortcomings.

The ideal is to send me PDFs as PDFs are what we need for publication, and they really are portable - everyone sees the same things, and we very rarely get errors introduced when they are adjusted because changing overall size, line weights, fonts or moving groups can be done without changing any relationships or text (usually).

In this case I think the problems came when I exported Graham's original drawing to pdf; it's by far the best if authors do the export themselves so they can check if any errors are appearing. Graham now produces his own PDFs and I recommend this approach to everyone.

Neil

um, pardon me if this is just a daft idea but in this electronic communication age could you not bat the mag layour drawings to the original contributor on a 24hour turn round time for checking. If you have written an article you have vested interest in it being printed correctly particularly dimensions. At least you would get a heads up for free.

regards Martin

PS I like the tailstock dial design. I made a George Thomas tailstock micrometer for my last Myford but now have the new style tailstock as I changed the lathe. Sometime I may make one to go with Grahams Saddle handwheel which I love to bits.

Good in principle, in practice often impractical as deadlines are tight and I would also need extra time for corrections to be made. I do occasionally ask people to check drawings where it look like there might be an ambiguity or missing dimensions etc.

Neil

Well I did say it might be a daft idea as I have no idea of your timelines etc.

Fortunately the Forum is quite good at 'off magazine ' corrections as has been demonstrated.

I'm sure you do pretty well all things considered Neil.

Best wishes Martin

Hi all.

Just a quick note of something I have found to anyone making an imperial one of these.

Based on the drawing, I think the idler gear will hit the thrust bearing.

Plenty of workarounds but worth keeping in mind.