# South Bend metric transposing gears



## David_R8 (May 5, 2021)

Just ran across these folks on the South Bend Facebook forum. Apparently they make metric transposing gears for the South Bend 9 as well as 'silent' gears for South Bend 13.
https://www.thegearmaker.com/gear-making/

Not cheap...
"Right now, they are $384.95. Not sure if we will be able to keep them at that price point in the future. They are in our web store and on eBay. Feel free to email directly"


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## Tom O (May 5, 2021)

Wow that’s pricey! I’ll have to look at getting the 4th axis going and trying some gears.


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## David_R8 (May 5, 2021)

I was mildly interested till I got the price. I have a horizontal/vertical dividing head and I'd rather try and make them than drop $400+ CDN on them...


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## Johnwa (May 5, 2021)

At one time you could get transposing gears for about 50£, at either arceurotrade or rdgtools.  They don’t show up any more tough.


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## Tomc938 (May 6, 2021)

Mr Pete (Tubal Cain) made 3D printed gears for his Craftsman/Atlas or Clausing/Atlas and was impressed by their durability.

If you would like to give it a try, and you don't know someone with a 3D printer, I would be willing to print them if you cover the cost of materials. Ran the software, and it came up with $3 for a 62 tooth gear.

If it is special size I can also design the gear for printing. (I'm not sure just exactly what you need, but at this price it's worth a shot!)

If you have or know someone with a 3D printer, just do a search on Thingiverse.


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## David_R8 (May 6, 2021)

I have an Ender 3v2 so I’ll have a gander through Thingiverse and see what I find.


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## Tomc938 (May 7, 2021)

Do you do design work?  If not, and you need something special, I am willing.  Enjoy having projects I haven't done before.

I use Fusion 360.


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## David_R8 (May 7, 2021)

Thanks Tom, I do a bit here and there but pretty basic stuff in conFusion360


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## Tomc938 (May 13, 2021)

Fusion 360 has a feature where it designs the gear for you.

If you enter the information as shown in the attached screen capture, you are off to the races.  Might take a couple of prototypes, (for things like backlash) but pretty sweet.

You can find it under "tools" and "Scripts and Add-ins" and scroll down to "Spur Gear".  Run the script, enter the data, extrude and you are done.


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## YYCHM (May 13, 2021)

Tomc938 said:


> Fusion 360 has a feature where it designs the gear for you.



Fusion crashed and burned when I tried it


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## Johnwa (May 13, 2021)

Just tried it, and it works!


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## YYCHM (May 13, 2021)

Johnwa said:


> Just tried it, and it works!



What scripting options did you use?  Seems you had to select a language, create, import, yada yada yada.  Eventually there was a run option, selected that and boom crashed.  And there were two spur gear options listed in the scripting drop down????


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## Tomc938 (May 13, 2021)

Yes there are two options.  They are a Python script and a C++ script.  Either will work.  Then next option after choosing one (they work the same) should be run.

And it SHOULD be that simple.  I chose a script the last time, not an add-in.  Maybe that's the difference?


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## YYCHM (May 14, 2021)

Tomc938 said:


> Yes there are two options.  They are a Python script and a C++ script.  Either will work.  Then next option after choosing one (they work the same) should be run.
> 
> And it SHOULD be that simple.  I chose a script the last time, not an add-in.  Maybe that's the difference?



Ok, worked second try.  Cool.


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## RobinHood (May 14, 2021)

Maybe you should model your 28T shaper gear we made and compare it the the actual specimen. Also, for comparison, model one with 20*PA and one with 14.5*PA and see how much of a difference there is in the tooth form on that size gear.


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## Tomc938 (May 17, 2021)

I love that you can change things up quickly and print a prototype.  On something like a gear I would print tough thickness with very little infill and see how it fits.  One thing I have found, however, if you need to use the same print resolution. Printed in 0.3 will give you slightly different dimensions from 0.2.


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## David_R8 (May 17, 2021)

So where does a person get the gear data?
(3D printer is tied up for the next while printing router parts but after that...)


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## YYCHM (May 17, 2021)

David_R8 said:


> So where does a person get the gear data?
> (3D printer is tied up for the next while printing router parts but after that...)



Can you extract anything useful from this?


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## David_R8 (May 17, 2021)

YYCHM said:


> Can you extract anything useful from this?
> 
> View attachment 14798


Yes, but I meant specifically the South Bend change gear data. I have no idea what the pressure angle or diametrical pitch might be. I'll google...


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## Tomc938 (May 17, 2021)

Are you talking about something like this? 

https://www.ebay.com/itm/124387115378

There is lots of information there, and if you are making a full set that need to work with each other, I would think you just make sure that you use the same pitch on all the gears and they should work fine.

I would be tempted to use the Fusion default settings and see what happens.


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## Tomc938 (May 17, 2021)

...and I think the diametrical pitch is software defined


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## PeterT (May 17, 2021)

The McMaster files might be perfectly fine but its hard to be certain. I've downloaded lots of their fasteners & hardware. Some take shortcuts on the threads for example & others seem like they would be spec because you can physically verify dimensions. I think they offer these files more to build CAD model assemblies & save you the effort of drawing common parts. And lets face it, it encourage you to click Buy while you're there as opposed to make by using their free file. McMaster doesn't make anything themselves likely pulling those files from gear suppliers, where you can find similar CAD models or at least accurate outlines. But again, they may be simplifications when it comes to details like root radius.

If you go to Youtube & search different keyword permutations of 'Solidworks + gear + design + parametric'... you will find a handful of videos that show step by step using classic gear formulas. I would think Fusion could replicate this. Maybe not a generic parametric tool but for sure a gear of interest. From the fusion link someone provided that kind of looks like what they did - built an integral utility tool.

Lastly I don't know much about 3d printing but I've heard people have had to make several fudge factor allowances for both absolute dimensions (4.000" CAD = 3.970 real life) and aspect ratio (a 4.0x4.0 CAD square is 4.00x3.95 in X&Y). These are just BS examples but you know what I mean. If its supposed to be circular & you have printed something eccentric with teeth superimposed, it might effect running. I dont know what kind of tolerances are acceptable in this application or if the material just wears in, but maybe do a simple donut print test to verify?

I've always wanted to know how much an EDM gear would cost to cut from a blank (keyway included!) but its like that $$ saying.... if you have to ask.....


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## buckbrush (Jun 1, 2021)

South end 9”, 10k, and Boxford 9” and 10” end gears (change gears) are 18 dp. This is not a standard pitch diameter. Standard is 12, 16, 20 d.p.

This is common with lathe makers change gears, my Harrison L6 has 14 d.p. Change gears. They use non standard pitches so you have to buy from them at inflated prices, or make your own, or look into an electronic lead screw drive.


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## RobinHood (Jun 2, 2021)

With the advent of Offshore “knock-off” tooling, even “non-standard” tooling is available:

https://www.rdgtools.co.uk/acatalog/18_DP_INVOLUTE_GEAR_CUTTERS.html

These are little pricier, maybe an Asian import version might be more affordable:

https://www.suncoasttools.com/crm/ItemPage.aspx?ItemNumber=5-860-185&VendorNumber=TOOMEX

Yes, just make your own; or make a couple of sets while you are at it and sell them -  your cutter costs will be covered...


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## Crankit (Jun 2, 2021)

Tony sells gears for SB and Boxfords

https://store.lathes.co.uk/parts/bo...n-sabel-etc-changewheels-tumble-reverse-gears


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## Johnwa (Jun 2, 2021)

For the transposing gears only the RDG #2 cutter is required. 55T-134T.


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## buckbrush (Jun 6, 2021)

Thanks for the info guys.


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## Johnwa (Jun 6, 2021)

I vaguely remembered buying a cutter  for making transposing gears.  I found it and am going to try cutting a gear out of delrin.  I don’t have a big enough piece for the 127T but can do the 100T.  I don’t relish the thought of cranking the mill bake and forth 100 times though so I might get sidetracked trying to automate the process.


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