# Gear Table for 10" Standard Modern Utilathe



## Jim329 (Feb 5, 2019)

I have the above lathe and would like to do some metric threading. I have seen one image of the identical machine that had a gear chart on the gear door although it is illegible. I attempted to contact the image owner but have yet to receive a response. Does anyone have the chart and can send me an image or direct me to a site with the info?


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## ducdon (Feb 5, 2019)

It should be  possible to create your own. With the info linked and a calculator or spreadsheet I think you could create your own. First step would be to see if you have a 127 tooth gear in your gear set. My lathe has an 8TPI lead screw. The 127 gear engages with  either a 30, 56, 60 or 63 tooth gear to get the correct metric thread pitch as opposed to the 100 suggested. I assume the rest of the conversion is taken up by the QC.

http://conradhoffman.com/metricthreading.htm


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## RobinHood (Feb 5, 2019)

I would contact StandardModern here: http://www.standardmodernlathes.com/index.html.

Give them your serial number, they can probably send you a manual specific for your lathe. They may also be able to provide you with the chart in question. They were very helpful when I needed info for my 9” Utilathe.
The Utilathes were never designed or made to thread in Metric. You will probably have to make (or come up with) your own change gears if you desire to thread in metric.


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## Brent H (Jun 10, 2019)

Hi Jim, 

I will be going over my "new to me" 10" Utilathe pretty soon with a fine tooth comb and I'll let you know if I find a suitable table.  A Question for you though:  Would you have the correct belt size for the 10" Utilathe?  The 11x20 is I believe a 5L330.  The pulley on my 10" was broken, I made a new one to OEM spec, however, Just wondering if the belt that is running on it is the right one.  I am not home now to see what it is, but if you have a number that would be great.


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## Brent H (Sep 26, 2019)

Hey Jim, 

Are you still looking/on this project?

I am currently Autocading a plan to make up a set of change gears and have made up a metric pitch chart for the gears.  The guy you took the pictures from, well  I watched the video and then went backwards engineering and figured things out (I think - LOL)

On the lathe he shows there is always the Quick change Gear box drive gear 127T  DP24 

The idler is changed out from the 83T to a 68T DP 16 to allow space.  The 68T drives another 48T DP16 that has the change gears pinned to it.

Change gears are 50T, 60T, 70T, 75T, 80T and 90T  DP24 and yield all the standard metric pitches

I attached the chart - let me know if there is anything wrong

There is the original 48 tooth still on the feed drive so you can swap back in the 83T gear and then have a standard lathe relatively quick.  I am working out how to machine the new idler plate as it needs to have a movable attachment point for the change gears so you can mate them up with the 127 tooth feed drive gear.

Also need to find some DP24 cutters to play with and of course ......time......


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## ducdon (Sep 26, 2019)

Workshop Practice Series Book #3 by Martin Cleeve has a pretty good section on cutting Metric threads on an inch lathe. Spells out the origins of the 127/50 tooth conversion gear set and formulae for calculating conversions. I think it's available from Busy Bee!


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## Brent H (Nov 11, 2019)

Found an old military manual with the conversion information and parts required to change over the 10" Utilathe from standard to Metric threading.  I have to do some checking against measurements but here are the key pages - I wish the parts one was a bit clearer:


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## Brent H (Nov 18, 2019)

So over the weekend I was working out a few things and reviewed a couple Youtube videos that were posted a few years ago by this Dan Cartwell? fellow.  He has "restored" or pretty much cleaned up and painted a few 10 and 12 inch Utilathes.   His filming and dialogue is not the greatest but I was able to stop frame a few video's and pick up a few bits of information as he was discussing what he was moving from one lathe to another. He very quickly goes over the metric conversion that was performed on the 10 inch Utilathe.  On a subsequent video for a 12 inch Utilathe overhaul he is swapping parts back and forth and changing over his 10 inch Utilathe to be metric - I got a good screen of his arrangement finally:






Armed with the intel that I was able to get from about 4 of his videos where he was quickly passing over this assembly and the new Army Manual it appears that the 10 inch is not set up as presented and that there was a modification at some point to eliminate a gear (40 tooth idler) and convert the 32 tooth idler to just a 68 tooth single idler.  This will have the effect to rotate the gear box in reverse of "normal" when the metric threading is being used.

I dropped the gearing into AutoCad and reverse engineered the bracket that you see in the picture above (and in the gear train sketch shown in my previous post).  I am not able to measure to be 100% on the assembly but I think this project is do able:






I set up on the auto cad and then set for the biggest gear (90 teeth) and the smallest gear (50 teeth)  Both rotations work out with plenty of adjustment.  A few mods need to be made to the lathe for full adaptation (like the securing bolt for the bracket and the Idler Bracket needs a pin located higher).  Looks like the Gear Bracket is pretty hefty (about 1 to 1-1/2" thick and it also needs a place to drop oil into the current shaft arrangement.  I checked out the figures on a website called "gear generator" and the gear position (X,Y axis stuff) all jives.






The assembly for the original gears shown on Youtube has the metric gears set up with 24 DP teeth.  I have a 22 DP cutter set so I changed the dimensions accordingly.  I will have to find some steel and another project can begin once a few others are complete.  

When looking for additional information I also located another rendition of the military manual that has been cleaned right up.  The pictures and sketches are not the best but everything else is good and corrections on bearings and seals is up to date.  I will be assembling a complete manual after I get my lathe up to snuff with the tail stock.


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## Hruul (Nov 18, 2019)

I think its Dan Cirtwill not Dan Cartwill.  Let me know if that is correct.  All I got with the first search was cartwheel videos.


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## Brent H (Nov 18, 2019)

Yep, Dan Cirtwill,

seems like he would be a good resource for things - perhaps parts but videos are  three years old. Doesn’t seem to have new tool vids


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