Metric Change Gears for SB 9A

[jocat54]

Hi Jocat,

I've been researching exactly the same thing myself for my 9A and hit this thread with a Google search. Can I ask you how many teeth were on the idler gear set you used and what sort of tool did you use to cut the gears? Was it a tool you ground yourself or did you buy and involute gear cutter?

I'm in the UK and am having a hard time sourcing the 18dp 14.5pa involute gear cutters. If I can't find what i need then I will have a go at grinding my own form tool and use a fly cutter.

Regards

I think that I used a 48t gear for the idler in that set up-----but it does not matter what the idler gear is as long as you can get engagement, it does not change the ratio. (any gear will work).

I bought some metric module cutters from http://www.ctctools.biz/servlet/the-628/hss-involute-gear-cutter/Detail
I did some research and don't remember which module was real close to the right DP (I think it was m1.25 or m1.5---way down the list on the link) Really believe it was the m1.25 module though. Just chose the number of teeth for each cutter. They are not exact but close enough for what I use them for.

 

[Mark_f]

I been trying to figure out how to do it on an SB 9 B. I guess you need the transposing gears but is a different gear chart needed since it doesn't have a QCGB?

Mark

EDIT: I seem to remember somewhere when I first saw the transposing gear setup that someone had said it did not work on the change gear lathe like the SB 9 B or C, but I have no idea if that is correct or not. That was why I stopped pursuing the idea.

 

[bogster]

I think that I used a 48t gear for the idler in that set up-----but it does not matter what the idler gear is as long as you can get engagement, it does not change the ratio. (any gear will work).

I bought some metric module cutters from http://www.ctctools.biz/servlet/the-628/hss-involute-gear-cutter/Detail
I did some research and don't remember which module was real close to the right DP (I think it was m1.25 or m1.5---way down the list on the link) Really believe it was the m1.25 module though. Just chose the number of teeth for each cutter. They are not exact but close enough for what I use them for.

Thanks for that information Jocat and the link to the CTC Tools website. I've ordered the M1.25 involute cutters I need at a very reasonable price including shipping.

 

[jocat54]

I been trying to figure out how to do it on an SB 9 B. I guess you need the transposing gears but is a different gear chart needed since it doesn't have a QCGB?

Mark

EDIT: I seem to remember somewhere when I first saw the transposing gear setup that someone had said it did not work on the change gear lathe like the SB 9 B or C, but I have no idea if that is correct or not. That was why I stopped pursuing the idea.

Mark I believe that it will work on a change gear lathe. A lot of my reading on this was from http://conradhoffman.com/metricthreading.htm and i think his is a change gear lathe (Logan). There is a lot of good reading there. Somewhere I did see a chart for a change gear lathe, I will see if I can find it again.

Having seen all your OUTSTANDING work on this forum---this would be a piece of cake for you.

John

 

[Mark_f]

Mark I believe that it will work on a change gear lathe. A lot of my reading on this was from http://conradhoffman.com/metricthreading.htm and i think his is a change gear lathe (Logan). There is a lot of good reading there. Somewhere I did see a chart for a change gear lathe, I will see if I can find it again.

Having seen all your OUTSTANDING work on this forum---this would be a piece of cake for you.

John

I'd like to try it and I would like to make the gear myself too, If I find the info and it will work.

Mark

 

[bogster]

I'd like to try it and I would like to make the gear myself too, If I find the info and it will work.

Mark

Hi Mark,

There are quite a few threads on various forums with good information on how to go about this. If you Google "South Bend metric threading" you will hit quite a few. Basically your starting point is to buy or make a pair of transposing gears - 127/100 is the classic but 47/37 work as well as Jocat54 has shown. Depending on how accurate you want to be and what metric threads you want to cut you might find this reference useful as well:-

http://ixian.ca/gallery/metric/metric.htm

 

[Mark_f]

Hi Mark,

There are quite a few threads on various forums with good information on how to go about this. If you Google "South Bend metric threading" you will hit quite a few. Basically your starting point is to buy or make a pair of transposing gears - 127/100 is the classic but 47/37 work as well as Jocat54 has shown. Depending on how accurate you want to be and what metric threads you want to cut you might find this reference useful as well:-

http://ixian.ca/gallery/metric/metric.htm

Thank you,

I am going to check this out .

Mark Frazier

 

[LEEQ]

tools for cheap is clearing out some south bend metric change gear stuff. Worth a look if only to see how someone else is doing it.