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Rebuilding a 10" Standard Modern Utilathe

@That-Guy, thank you for the kind words.
I put the gearbox back together minus the one missing gear, so I only have 2 high and 2 low.

It's enough to get it spinning under power, man is this machine loud, I've never run a gear driven lathe before so I'm sure they are louder than belt driven but this is so loud I have to wear ear muffs.
I also noticed while cleaning everything up that there are few other gears inside that have been remade, that is probably where the noise is coming from.
Also drilled out the drive pulley to 3/4" and tried my hand at broaching, it needed some fine tuning with a file but it's running true.
IMG_1377.JPG

I finished up the tail stock today and mounted it, it looks a little strange being a completely different design than the original, but only me and some of you guys would notice it.
The base ended up just a hair lower than I wanted but a 0.008 shim took care of that. The first time I have ever used a fly cutter for the final cut on the tail stock base and wish I had set up a shower curtain around me and the mill, little crumbs of cast iron everywhere, 20ft. away.
I'm making chips!
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skippyelwell said:
@That-Guy, thank you for the kind words.
I put the gearbox back together minus the one missing gear, so I only have 2 high and 2 low.

It's enough to get it spinning under power, man is this machine loud, I've never run a gear driven lathe before so I'm sure they are louder than belt driven but this is so loud I have to wear ear muffs.
I also noticed while cleaning everything up that there are few other gears inside that have been remade, that is probably where the noise is coming from.
Also drilled out the drive pulley to 3/4" and tried my hand at broaching, it needed some fine tuning with a file but it's running true.
View attachment 57217

I finished up the tail stock today and mounted it, it looks a little strange being a completely different design than the original, but only me and some of you guys would notice it.
The base ended up just a hair lower than I wanted but a 0.008 shim took care of that. The first time I have ever used a fly cutter for the final cut on the tail stock base and wish I had set up a shower curtain around me and the mill, little crumbs of cast iron everywhere, 20ft. away.
I'm making chips!
View attachment 57215View attachment 57216View attachment 57218View attachment 57219View attachment 57220View attachment 57221
Click to expand...
outstanding work
 
skippyelwell said:
I'm making chips!
Click to expand...

Awesome! Making chips is what it's all about!

Had to laugh at your first fly cutter experience! Wait till you use a big face mill! I like to make cardboard chip shields (see cardboard thread) to contain the shrapnel (flying swarf)! I just set them where they are needed. Works good enough for me.
 
Ok @skippyelwell I have started on your new double gear. It will be made from 2-1/2” 4140 steel. I cut the blank today, sized it to 2.024” in length (as required) and then drilled and reamed the centre to 0.875 or 7/8” as required. It fits perfectly onto my blank shaft and arbour for the gear making process. Tomorrow it will be chucked up in the 4 jaw and the gears sized. After that it is onto the mill for some dentistry- as in making teeth!

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I’ll send you some video of my machines running later on today.
 
Got the rough blank done today and it is all to spec within about 1/2 thou. The dentist visit is next after I do some milling machine tune up and figure a way to lift my “way to big” rotary table and chuck onto the table. My old shop had a nice beam for the chainfalls - will have to work on something similar…..

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Set in the 4 jaw and big gear OD sized.

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After smaller gear OD sized I took the parting tool and cut reliefs on both sides to allow me to hog out the middle down to 1.372”

The final blank awaiting its dental appointment:

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I will cut the keyway at the end of the machining. That way, if my broach breaks or the keyway goes south I can curse and swear and beat the tar out of the project without feeling guilty.

The feats of strength:

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@skippyelwell : can you confirm the keyway size? It “should be” a Woodruff key #9 (3/16 x 3/4 Dia)
 
Great day at the dentist today for @skippyelwell ‘s gear project. It grew teeth - both upper and lowers!!

Setting up to cut teeth: a typical tooth cutter

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This is the cutter for the 26 Tooth part. Each cutter varies in thickness by several thousands so measure your cutter to set up dead centre when cutting the teeth.

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The cutter is just touching the top of a 0.5000 round bar so centre is -0.616 in this case. (Cutter is 0.232” thick)

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Cutting depth is a pretty simple calculation for DP gears as it is 2.157/pitch or 2.157/16=0.135. As this is pretty “hard” material I cut the teeth in 2 passes.
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After cutting the teeth I broke the tooth edges on the lathe and then set up for broaching the 3/16” keyway.
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It is important that the cutter is fully supported at the back by the arbour. I used some 0.010” shims to move the cutter at each pass -
Lots of oil and its a good idea to land the broach on a towel instead of the concrete floor.


Sexy!!

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Nothing left to do but post it and hope it fits properly!!

@skippyelwell - please PM me your address!

Side notes:
- make sure your dividing head is square to the table and there is no run out on the arbour your gear is mounted to
- I was running the cutter at 240 RPM and a slow feed on the power feed shots of oil every so often
- https://www.bilar.co.uk/cgi-bin/division-calculator.pl Is the calculator I use for the dividing head. Works well and is simple
 
Drop dead beautiful. I love a nice double gear like that. Nice job. Even nicer to do that for someone else.

Brent H said:
Each cutter varies in thickness by several thousands so measure your cutter to set up dead centre when cutting the teeth.
Click to expand...

I have never done this Brent. Why does it matter? Isn't it a net sum zero game? I only ever just eyed it. Maybe it matters more on a really tiny gear. Once you go all the way around you are back where you started no matter whether you were a bit high or a bit low or dead nuts. No?
 
I think much like cutting a key way, you want it on center. Otherwise the tooth sides will not be parallel to the tooth sides of the engaging gear. So likely either the tip of the teeth and or the root? may not have the nessacy clearance. Likely not a problem with a very small misalignment at slower speeds and large teeth.
I could be wrong about this, only be second time today!
 
Bandit said:
I think much like cutting a key way, you want it on center. Otherwise the tooth sides will not be parallel to the tooth sides of the engaging gear. So likely either the tip of the teeth and or the root? may not have the nessacy clearance. Likely not a problem with a very small misalignment at slower speeds and large teeth.
I could be wrong about this, only be second time today!
Click to expand...

I think you are right but I also think it's a matter of degree. I don't think 5 thou one way or the other matters. The smaller the gear the more it matters and vice versa. Regardless, I'm interested in hearing Brent's view of it.
 
@Susquatch : so, if you’re too high or too low you will plow off a bit more on one side of the gear tooth or the other. - perhaps a couple thou would not matter much, but the cut being true helps in other ways:

I forgot to lock the quill at the first cut and was a tad low - well, that resulted in a “screw” type cut happening- stopped things quickly but- the closest you are to “bang on” the less chance of the cutter wanting to load your work. The force up or down can lead to less than stellar finish and, depending on your setup could produce failure.

The difference in cutter thickness was substantial- in small terms—so 0.218 on one cutter and 0.232 on the other. Swapping the cutters and not adjusting centre was not an option as the difference would screw any spec.

That all said, it is best to have the machine on hand and “fit” the gears so all is grand when running.
 
Brent H said:
That all said, it is best to have the machine on hand and “fit” the gears so all is grand when running.
Click to expand...

Amen.

And all good points too. Plus what @Bandit said.

I still think it matters much less on bigger gears, but I'll pay more attention in future.

Again, really nice job.
 
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