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Free hobbing - a rogue method?

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  • J Tiers
    replied
    Originally posted by Peter. View Post

    ....at least they make sense...
    Yah, I thought for a short time he was "termite's twin bro".

    Still, while they did not appreciate it much over there, it's an interesting subject. I'm still looking for the other reference I had which referenced free hobbing spur gears.

    For our purposes, here, hobs are expensive, quite possibly more each than a set of the (inferior) form cutters, and if good form cannot be guaranteed, it may or may not be worth pursuing. Doing it right requires a "universal" mill, or some good positioning with a vertical mill, plus a gearbox and change gears for moving the blank in synch. More costs.

    It should be possible to MAKE reasonable hobs, since the hob teeth are simple "rack form" (although makers do have some "special sauce" modifications. So there may be a lower cost (but more work) way to get into the business of hobbing.

    There was a series in the magazines a fairly long time ago about hobbing gears, I believe A search of the index in the topics should find it.

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  • Peter.
    replied
    Originally posted by J Tiers View Post

    I mean we've got some folks here who can be "blunt and plainspoken", but....
    ....at least they make sense...

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  • J Tiers
    replied
    Originally posted by Robint View Post
    Well gents my OP has been usurped by DWD which is kinda rude since I made the effort to contact him first off as I discovered his earlier work some 2 years ago and give it proper accreditation which is what ethical worker do or you very quickly get shot down and discredited as a plagiarist

    ..................

    I shall miss the hostility from bigoted armchairs and thanx to all the 2000 viewers who dropped by over the last 5 days


    Robin has left the Building
    Sheesh......

    Dude, have fun at PM, I'm sure you will. (EDIT: He sure did.........!! ) But, from the looks of this, frankly, we won't miss yah.........

    I mean we've got some folks here who can be "blunt and plainspoken", but....
    Last edited by J Tiers; 10-14-2021, 02:26 PM.

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  • Optics Curmudgeon
    replied
    You sure you're not from Illinois? You sound familiar....

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  • Robint
    replied




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    I shall miss the hostility from bigoted armchairs and thanx to all the 2000 viewers who dropped by over the last 5 days


    Robin has left the Building




    Last edited by Robint; 10-15-2021, 06:49 AM.

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  • The Artful Bodger
    replied
    There is nothing new under the sun, not even on PM!!

    https://www.practicalmachinist.com/v...x-head-373736/

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  • The Artful Bodger
    replied
    I must say that I have had very informative and friendly conversations over there.

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  • Jim Stewart
    replied
    Don't forget to grab a bowl of popcorn...

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  • nickel-city-fab
    replied
    Originally posted by The Artful Bodger View Post
    I am heading over now to see if I can get a front row seat!!!
    I was just over there, no sign yet. Will continue looking.

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  • The Artful Bodger
    replied
    I am heading over now to see if I can get a front row seat!!!

    Leave a comment:


  • Jim Stewart
    replied
    Sure, head on over to PM. They'll welcome your wisdom gratefully. Really. I guarantee it.

    -js

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  • sid pileski
    replied
    "BTW thanx for the tip about going to practical machinist - you are right they do have some really knowledgeable people there - I should get on well as I will be in good company"

    You really are full of yourself!

    Why would you even bother trying to educate us dumb asses?

    Don't let the door hit you....


    Leave a comment:


  • davidwdyer
    replied
    Originally posted by Mcgyver View Post

    I just went into the archive and pulled that issue. I won't copy it, its under copyright, and we're here on this site by the good graces of a magazine publisher. Model Engineer and other mags are a wealth of info but they are often hard to give away....so if someone wants a copy they are out there to buy. The second part, in the April 4th issue, is the issue Eric Whittle began his great series on the Aero V8 - great stuff! On the gears, I'll describe the basics below and anyone can fill in the details, i.e. common knowledge available through searching

    Its a good article and gives lots of info on making hobs. The hob is held in the lathe and the work mounted on an axle which is bolted to the vertical slide. In his set up, the axis of work end ups parallel to the X axis (cross slide) and is positioned under the hob (on the Z axis). The cross slide is the feed, and the vertical slide the depth. As anyone with any gear knowledge has said repetitively in these threads, the verticle slide assembly (on the cross slide) is rotated (around the Y axis) to match the hob's helix angle (to a good tooth form) and the work is rough gashed in advanced. That's the short synopsis of the article. He gives a detailed description of making a gear and also goes onto helical gears.

    This should create a reasonably good result suitable for lots of purposes, however when making ones own hobs the challenge becomes getting the hobs pitch to that of a standard diametrical pitch or module gear. IT can be done with change gears (or a DSG does it)....or if its a closed system, gears only used with themselves, it won't matter. Of course if you are buying a hob, its moot.
    I would love to have a copy of that article. Where can I buy it? That sounds like a wealth of information!

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  • nickel-city-fab
    replied
    Originally posted by Robint View Post
    NCF

    BTW thanx for the tip about going to practical machinist - you are right they do have some really knowledgeable people there - I should get on well as I will be in good company
    Beware of Practical Machinist, they do not tolerate as much as we do here -- that's why I hang out here, the company is much more polite and easy going. At PM they have no problem with making mincemeat out of you before 8 AM in a very public and embarrassing way if they feel like it -- they are very serious folks over there, working pros. Speaking from experience.

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  • The Artful Bodger
    replied
    Originally posted by Robint View Post
    FWIW this much derided thread has had 1700 views in 4 days
    But no likes?

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