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,

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

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.

Yes Graham, also glad to see you back!!

Best wishes,

Tony

Thank you all for your kind regards,

Gray,

Gray

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

regards Ian

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.

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

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

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.

Thanks Graham

I can see what you're saying, would you have a photo of the gear cutting bits, or the setup you used?

Thanks,

Brian

I have found the photographs quicker than I thought,

The above was when I made the sample Super 7 Handwheel dials for the original article in EiM. This cutter incidentally had been used to produce approx 500 dials over the course of 30 years. The cutter only requires touching up on the top surface to restore the cutting edge.

Regards

Gray,