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Newbie gear cutting question

C

canuck750

Active Member
Premium Member
I have no experience cutting gears but I do want to try and cut a new gear in aluminum.
I recently picked up an Atlas MFB in very good shape and I have a couple sets of gear cutters, one set is an M1 metric module and the other a DP 16.



The gear I want to replicate is stamped M1.5 and Z25, o assume this to mean it is a metric gear of 1.5 module and 25 teeth.



Consulting YouTube university I found a video explaining g how to convert metric module to diametric pitch.

If I divide 25.4 by the diametric pitch of 16 I get a module of 1.587, I assume the closest DP to a module of 1.587 is a diametric pitch of 16?



The DP 16 cutter for the 25 tooth gear is the one pictured above,
What are the numerals after DP16?? It looks like 14.5 degrees, do I need to be concerned about these markings?

YouTube says if I know the number of teeth, the diameter of the gear blank and the DP every thing I need can be figured out from there, I assume the critical info I don’t have is the depth of cut??

I have a Vevor dividing head to index the gear blank on



Looks like I need to make up a heavy steel plate to secure to the table to mount the dividing head and tail stock with an arbour mounted between centers, gear blank secured on arbour with sufficient clearance for the table to travel and clear the dividing head, sort of fashioned on the index accessory that Atlas sold as an option.



Any guidance into this new to me adventure is very much appreciated.

Thanks
Jim
 
canuck750 said:
The gear I want to replicate is stamped M1.5 and Z25, o assume this to mean it is a metric gear of 1.5 module and 25 teeth.
Click to expand...
Ok so you will need an M1.5 cutter, number 4. There is no 'conversion' that will work to create an M1.5 gear from a DP cutter.
canuck750 said:
The DP 16 cutter for the 25 tooth gear is the one pictured above,
What are the numerals after DP16?? It looks like 14.5 degrees, do I need to be concerned about these markings?
Click to expand...
14.5 pressure angle, 21-25 refers to the range of gears it will cut. It is a #4 cutter.
Your Module cutter is 20 degree PA and is incompatible with DP designated gears.

Gears are cut on a blank with a specific diameter - e.g. Dia = Module * (N+2)

The depth of cut is determined by the tooth form - DoC = 2.25 * Module

Machinery's Handbook is the reference for all gear info. Ivan Law's book Gears and Gear Cutting is a valuable reference for beginners too.

Small gears like this are usually cut in a single pass. Low cutter RPM (60-80), lots of lube and a slow feed will do it. Stop at the slightest sign of chatter.

The arbors must be made accurately and I strongly suggest a tailstock. Oh, and you might want to reverse those chuck jaws!
 
Im not an expert, but i have cut several gears on my Chinese dividing head....enough to know that if i can buy the gear (or one that can made to work in some fashion), i will buy it, every time.

you will need to buy the correct module cutter for the tooth range, like @Arbutus said there is not a conversion.....good thing for you, module gear cutters are easy and cheap to get, ali express, buy the one you need, usually around 10$ a piece, or the whole set for around 80$. The cutters have tooth ranges, so if your buying one, pay close attention you buy the correct one.

Like already mentioned, your arbors need to be VERY tight, preferably with a key, you dont want any slop or chance the gear can turn...because if it does that will bite you, 70 teeth in, tailstock support is also highly recommended

The Asian dividing heads have a fair bit of backlash, make sure you take up that backlash in the same manor every tooth, and lock it down, every single tooth, if you don't, you'll find out when the gear is done and your try to run it. So if you go 1/4 turn past and come back to your hole, do that, every time, whatever you do to take up the backlash, do it the same, every tooth, and lock it down every time.
 
Being short in the bed such as it is, I would remove the chuck all together and put the workpiece between centers. Dead easy to swap from lathe to mill and you don't loose all that precious space the chuck takes up.
Turn the arbor between centers on the lathe, turn the gear blank on the arbor, and swap it all over to the mill for dental work....... Of course the thing I make best are mistakes.....so.. :rolleyes:
 
Thank you for all the great responses!
I have much to learn. Now to find a metric 1.5 module cutter for the 25 tooth gear I want to replicate.
 
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