# atlas lathes gear cutting fixture.....



## eric chilton (Oct 27, 2018)

hi my first time posting on this site..... im in the process of making the atlas gear cutting fixture from the prints floating around the internet..........its going pretty good so far ...but i keep looking at the print and im wondering why they chose a boston gear nb72 to have on the indexing end of this fixture ........the fixture has a .500 1/2-13 threaded end on the blank end and a .625 stub with 1/2-13 threaded portion on the indexing end ......is the 72 tooth gear relevant to making more gears with less teeth and smaller diameter ? if anyone knows this info please pass it on to me as there is no instructions with this once i get it done ..........tia.........eric


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## CluelessNewB (Oct 27, 2018)

The plans I have seen used Atlas change gears, maybe different plans?   Anyway I suspect 72 was used because it would allow you to cut gears with 
2, 3, 4, 6, 8, 9, 12, 18, 24, 36 and 72 teeth.   The design that I saw was adjustable and could accommodate smaller gears, maybe 72 was the largest gear that would not make the design unwieldy.  

This calculator will give you all the factors of a given number which is also all the different number of teeth you can cut with a specific gear: 

  https://www.mathwarehouse.com/arithmetic/factorization-calculator.php


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## eric chilton (Oct 27, 2018)

this is suppose to fit the milling attachment for the lathe ......the whole fixture is only 8 9/32 long ...thanks for the info ! im just now getting into cutting gears /splines ...i have a bridgeport clone and 2 atlas lathes a 6" and a com 12" .....i figured this might come in handy some day ...its better to have a tool and not need it than need it and not have it ...lol thanks for the reply...........eric...


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## eric chilton (Oct 27, 2018)

oh i forgot to say i dont have either milling attachments but have started to make my own for the 12" lathe ... i know the atlas is not very ridged in doing this kinda work but i figure lite cuts and it might get me out of a bind one day.................


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## dgehricke (Oct 27, 2018)

You can find this on the internet search Popular Mechanics Oct. 1954 page 223 theres a very nice indexer 
dgehricke


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## eric chilton (Oct 27, 2018)

cool thanks ill check it out ............


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## eric chilton (Oct 27, 2018)

that is like what im making.......a little longer in the body of it and no collet feature ...but i might have a go at this one later on ..thanks again .......eric


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## dgehricke (Oct 27, 2018)

No Problem check for google book downloader then you can download the article and print it.
Regards
dgehricke


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## eric chilton (Oct 27, 2018)

ive been saving the issues to my favorites ..but i didnt know you could download them and print them ....thanks again ....looks like i just added more work to my shop lol thanks again


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## dgehricke (Oct 27, 2018)

That book downloader is good for Mac not windows but I'm sure there is something in the windows world thats equal.
dgehricke


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## eric chilton (Oct 27, 2018)

thanks for the heads up on that ...im on windows ....ill look and see what i can find .......i just found a goober in this print so i am trying to figure how i am gonna fix a hole i drilled in it ...probably just weld it up and redrill...in the print it has 4 equally spaced holes at .1875 from the edge both in x and y .it says to drill a 17/64 clearance hole all way threw and 82* countersink for 1/4-20 flat head screw ....by the time i countersink there will be no edge left in the flat.......so im contemplating using 8/32 screws ...i am using digital read out and the edge located on the vice ..... .....lol


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## dgehricke (Oct 28, 2018)

Eric,
Make your self a pin for the hole silver solder in place and after clean up redial the proper size.
Good luck
if you need the article I can send you a copy but I can't post it here send me an email address and I'll send you 2 of them one from popular mechanics and the other from Atlas.
Regards
dgehricke@yahoo.com


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## eric chilton (Oct 29, 2018)

dgehricke yes i would like the copies of the prints ....and your idea is what im gonna do ,,,,my email is hyme64@yahoo.com ...thanks again ......eric


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## eric chilton (Oct 29, 2018)

i have alot of the old books and prints on accessories for lathes and mills and try to build them from time to time ....but i run my own fabrication business 6 days a week ...its a one man show so time is limited most of the time ........the last thing i made was the offset center for the tailstock for turning tapers ...i still need to make a new dead center piece for it with a longer nose because there is not enough room to clear the fixture with the tool to work on the end of the shaft ...........lol so i was gonna make one out of o1 tool steel with a long nose on it to fix the problem ...........when i need it is when ill get around to making it ...............eric......


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## dgehricke (Oct 29, 2018)

Eric,
 I made that same tool I'm to lazy to move the tail stock I got the drawings and info from Popular Mechanics who da thought ?
I'm retired and getting older with each passing day I work on something in my shop every day.
Later
Regards
dgehricke


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