Gears and Gear Cutting on the Milling Machine?

HMF

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Hey Guys,

This is a LOT to ask, but I address it to those of you with experience making GEARS on your manual milling machines using a dividing head.

Is there anyone out there willing to do a photo-essay on how to make a stud gear, or other replacement gear for your lathe using a manual milling machine?

I know it is a lot to ask, but it really would be helpful to us newbies.

Thanks in advance,


Nelson
 
chengdave2003 link=topic=1598.msg9576#msg9576 date=1302439733 said:
I've got a lot of new-to-me terminology to learn. And I need to start looking for some of those cutters...

Dave
If you find a cheap source for gear cutters, especially 14 1/2 degree pressure angle, please let us know. These cutters have gotten expensive the last few years. Oh, and be careful with buying on ebay. Some of the sellers there think anything round with teeth on it is a 'valuable gearcutter'.
 
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Gear cutting, Ive only done it twice. I will in the near future be making up a few gears for my American lathe. Starting with a 127 tooth gear, I will be making up a few differant tooth counts. Im determaned to cut metric threads on my lathe.

I will be using a rotary table as thats what I have. Not going out looking for a dividing head just for this job. I plan on giving this a go when the weather is a bit warmer here.

Im hoping the out come is good, but whats better than making the parts for your own machine. Im going to use
Marv Klotz,s rotary table program, used it before, worked out well.

Ill be keeping my eye on this thread, just incase there is any major (gear heads ) in here. ;D

Paul
 
I've done gears using my home built rotary table turned vertical. You have to figure out a tailstock support and a way to eliminate play between the gear arbor and the rotary table. The tailstock from my 6" Atlas lathe worked well for me. The setup is very similar to the one in the Youtube video.
I wrote a spreadsheet to give me the degrees for each position. My table was graduated in decimal degrees, so the spreadsheet was to two decimal places. With it I made the two gears (37 & 47) that can substitute for the 127 tooth gear in my Logan lathe. This combo gives metric thread accuracy to within .02% of true metric.
I have found that larger diameter gears can be most easily made using plate stock. For the 7/16" wide gears for the Logan, I sawed out rounds of 1/2" CRS plate, drilled and reamed a center hole, and faced and turned it to size on an arbor. The same arbor was used to hold the blank while milling the teeth out. For some larger gears you may need to take two passes, or rough out the teeth with a slitting saw before finishing with the gear cutter.
I learned about gears BI (before internet), but I have found the book Gears and Gearcutting by Ivan Law to be a good and relatively inexpensive introduction to the subject. You may have to do a bit of translation from English to American, but it does a good job of explaining the basics, as well as showing you some good home shop machinist type tricks.
 
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toolingjim link=topic=1598.msg10639#msg10639 date=1302921975 said:
chengdave2003 link=topic=1598.msg9576#msg9576 date=1302439733 said:
I've got a lot of new-to-me terminology to learn. And I need to start looking for some of those cutters...

Dave
If you find a cheap source for gear cutters, especially 14 1/2 degree pressure angle, please let us know. These cutters have gotten expensive the last few years. Oh, and be careful with buying on ebay. Some of the sellers there think anything round with teeth on it is a 'valuable gearcutter'.

I don't know what would be considered expensive, but this outfit has them http://www.victornet.com/cgi-bin/victor/alphabetic/Gear-Cutters-14-1-2-deg-11-DP-to-18-DP/1188.html
There are 3 other pages, with more sizes.
 
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Jim/ Mike

Thanks for the input
I have a 12 inch rotary table V/H, and will be mounting a 4-jaw chuck on it to hold a arbour I will make up. I will most likly have to have a key way in the arbour and gear blank to hold it steady while the machining is going on. I do have a very stout
tailstock to hold the other end of the arbour, so thats no problem.

Im still doing alot of reading about diametrial pitch DP and pressure angles PA . I know there is other tooth counts that sub the 127 tooth. The thing I still have to sort out is the DP for this. The DP on a 127 tooth will apparently dictate the OD of the gear. The OD still needs to fit inside the cover on my machine. My Manual gives me all the infro for the stock end gearing including the tooth counts, DP and PA , but when it comes to the input for the Metric conversions gears ,it doesnt give the DP and PA, just the tooth counts..

The manual even goes as far to give me all the different stud gear counts, and the threading charts as to set up for all the metric pitches. So Im trying to keep it that way, as the factory has allready figured it out. It will be nice to just go to the chart, and look up what set-up, get it set, and cut my choosin metric thread., just a few more things to sort out, before I get into this. The only other gears Ive done where to reproduce a couple of spur gear that had a few teeth knocked off them. That was easy in comparison to what Im attempting to do now. ::)

Paul 8)
 
8ntsane link=topic=1598.msg10872#msg10872 date=1303087052 said:
Jim/ Mike

Thanks for the input
I have a 12 inch rotary table V/H, and will be mounting a 4-jaw chuck on it to hold a arbour I will make up. I will most likly have to have a key way in the arbour and gear blank to hold it steady while the machining is going on. I do have a very stout
tailstock to hold the other end of the arbour, so thats no problem.

Im still doing alot of reading about diametrial pitch DP and pressure angles PA . I know there is other tooth counts that sub the 127 tooth. The thing I still have to sort out is the DP for this. The DP on a 127 tooth will apparently dictate the OD of the gear. The OD still needs to fit inside the cover on my machine. My Manual gives me all the infro for the stock end gearing including the tooth counts, DP and PA , but when it comes to the input for the Metric conversions gears ,it doesnt give the DP and PA, just the tooth counts..

The manual even goes as far to give me all the different stud gear counts, and the threading charts as to set up for all the metric pitches. So Im trying to keep it that way, as the factory has allready figured it out. It will be nice to just go to the chart, and look up what set-up, get it set, and cut my choosin metric thread., just a few more things to sort out, before I get into this. The only other gears Ive done where to reproduce a couple of spur gear that had a few teeth knocked off them. That was easy in comparison to what Im attempting to do now. ::)

Paul 8)

For what you're doing, the most important thing is to find out the DP and PA of the gear(s) you will be connecting to. Your gears must be the same DP and PA. The book I mentioned as well as Machinery's Handbook contain all of the formulae you will need after that. Do your best work. While geartrains on a lathe have some leeway for adustment, care in manufacture will give quieter, smoother running gears.
 
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Charlie/ Jim

Thanks for the links, They all help in my learning curve.
I know that all the gears in the end gearing are 12DP 20o PA
But , I have the manual, and it shows a 127t/ 60t gear. Now to use that DP , the 127t gear will end up 10.750 Diameter.
That is not going fit in the end cover. I can get a 7.5 to 8 inch in that spot max.

I do know that some other lathes use a different DP on the metric converion gears, but Im in the middle of try ing to figure out what Sidney put in these machines. They did change it , and that bracket that swings as well. I thought that bracket would be slotted behind the gears that are bolted to it, nope, no slots in that thing, ecept for the two ends for back lash ajust ment. So my search goes on.

Thanks guys
Paul
 
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