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It's there anyone out there that can make a hobbed out gear?
- Thread starter Jbonez
- Start date
- Replies 10
- Views 1,744
johnoder
Diamond
- Joined
- Jul 16, 2004
- Location
- Houston, TX USA
Might be helpful - note the many pages
http://www.practicalmachinist.com/vb/south-bend-lathes/thread-dial-kits-any-interest-128605/
http://www.practicalmachinist.com/vb/south-bend-lathes/thread-dial-kits-any-interest-128605/
johnoder
Diamond
- Joined
- Jul 16, 2004
- Location
- Houston, TX USA
I see I have the new 3/4-8 RH Acme tandem tap if anyone wants to play hobbing like in above linked thread. You'll have to buy the tap.
Richard King
Diamond
- Joined
- Jul 12, 2005
- Location
- Cottage Grove, MN 55016
Member Zahnrad Kopf (his handle on here) owns a gear shop up in Milwaukee I think he calls it American Gear.. and I bet he could help
Monarchist
Diamond
- Joined
- Oct 2, 2012
- Location
- Sol, Terra
A threading dial is but an 'indicator'. The only 'power' it transmits is enough to overcome friction of its mounting shaft. They don't REALLY even have to be metal.
More homework, and/or details of your specific machine, and several folk can probably point you to a ready-made or salvaged one a great deal more economical than having one custom fabbed.
Hard to imagine you'd have to 'make' one for a machine or lead-screw pitch as common as a South Bend.
Bill
johnoder
Diamond
- Joined
- Jul 16, 2004
- Location
- Houston, TX USA
Fifty years ago I made a MAPLE (hardwood) one for my twenties 13 X 5 Series O SB. I'll bet its still doing the job
Dan from Oakland
Titanium
- Joined
- Sep 15, 2005
- Location
- Oakland, CA
What pitch is your leadscrew, lh or rh and what is the OD?
Gonna take a circular pitch hob, but I may have one. Won't be axial pitch unless I have a worm hob the same pitch. John posted 3/4-8 RH- is that correct?
Dan
Gonna take a circular pitch hob, but I may have one. Won't be axial pitch unless I have a worm hob the same pitch. John posted 3/4-8 RH- is that correct?
Dan
Monarchist
Diamond
- Joined
- Oct 2, 2012
- Location
- Sol, Terra
For something like this I'd think you could use an acme tap run between centers, and fixture the gear on top of the compound to hob it yourself. The gear blank would have to be able to spin, but you should be able to just run it in against the tap and have it do the job. Fixturing and centering you can work out, T nut, a bolt for an axle, appropriate washers for height setting, etc. Gear would need to be something not terribly hard, a hard plastic would probably get it done just fine. Might even be able to take a hunk of acme rod of the proper size and pitch and cut some flutes into it and get the job done if you don't want to spend the coin on the tap.
johnoder
Diamond
- Joined
- Jul 16, 2004
- Location
- Houston, TX USA
Using an ACME tap as a hob......
http://www.practicalmachinist.com/vb/south-bend-lathes/thread-dial-kits-any-interest-128605/
http://www.practicalmachinist.com/vb/south-bend-lathes/thread-dial-kits-any-interest-128605/
Dobermann
Hot Rolled
- Joined
- Jan 2, 2014
- Location
- North Carolina
The method described using an Acme tap cutting a blank on the lathe is essentially what I did to make my threading dial for my 9 Jr. a number of years ago. I made a duplicate of the lathe's lead screw (but only about 6" long of course) and then ground some flutes into it so it could function as a cutting tool. I counted the number of teeth on my dad's threading dial on his 9 Workshop lathe and measured the OD of his gear. I made a vertical post which sat on top of the compound for the gear blank to rotate around while the cutting was going on. It turned out that I had to "fiddle" with the OD of the blank a little bit to get the number of teeth required to come out but I was able to cut a perfectly satisfactory gear for my homemade threading dial and it's functioned perfectly for a number of years.
