Rodregues DVD on Gearcutting

[John Stevenson]

It's just that all the way thru the DVD he refers to Pi as 3.1461 and not 3.1416.
Pi is used a lot in gearcutting and all his references are to the fomer number making all his calculations incorrect.

Didn't count but was probably a total of 12 times.

Also when hobbing a gear he tilts the dividing head to the helix angle of the hob.
this is incorrect and will not compensate but just cut a wider tooth form than is correct for the size.

Probably makes up for Mexiacn Pi

Sir John.

[John Stevenson]

JCHannum,
No part two at the moment.
I put that on hold as at the time I thought others had covered it quite well.
My article on gear cutting is mirrored to an extent in Ivan Laws briliant book Gears and Gearcutting and that's a hard act to follow.

Later Ivan and Giles parkes came out with a sensible way to make hobs, again hard to follow.

In the meanwhile things have moved on.
Hobbing which was out of most but the serious users grasp is now becoming more viable.
I have just had some samples of some Chinese HSS and solid Carbide hobs to try and they are very good, suggested retail figures from the supplier will make this affordable, in a lot of cases better than second hand or Ebay.

Add to this the electronic side of the hobbing setup which is again now within easy reach and the advent of DVD and screen media to get ideas across and I feel that the time is ripe to address this.

This was one of the reasons that I bought this DVD, to look at presentaion and layout and I wasn't impressed.

Not saying at this point I could do better but to be honest if I couldn't improve on this I wouldn't go this way.
[EDIT] I'd also try to improve my spellink

Still a long way off but we have winter and dark nights ahead.

Sir John.


[This message has been edited by John Stevenson (edited 10-20-2005).]

[wierdscience]

Awh hell it's just 3.14,good enough for most things

I have seen his video,it's boring,but you can produce some useable gears using the methods described.I did also notice he is severly limited in equipment which explains a lot.The whole time I was watching it I kept thinking gee,I wish he had a B-port

My quess is he found out he could make gears with the equipment(limited) he has and wanted to share that info for a price.

I think the methods he prescribes will produce gears good enough for use in scale models,but not for commercial use.

Now if somebody I know would just package a set of plans for that spiffy gear hobbing setup he has things would be easier the world over Just think,you could sell them on Ebay

[madman]

John while were on the subjecy whats a boffin. Thanks

[John Stevenson]

Boffin is a top professor, often associated with someone at the limits of their expertise.

Short step away from the mad professor image.
Einstein is a good example.

Sir John.

[ERBenoit]

<font face="Verdana, Arial" size="2">whats a boffin. </font>

Boffin is you know, like scroggin'.


[This message has been edited by ERBenoit (edited 10-20-2005).]