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Re: Reducing Shaft Diameter Without a Lathe

You could probably mount the motor to something and build a jig to hole the file so it can only go down so far, which should be your final dimension.

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Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by Shootr

Yeah, wheel. But in my world, a grooved pulley is a sheave, and a pulley is what we put on front and back of conveyors - but nobody seems to know that so its easier to call everything a pulley.

Same here for belted conveyors.

Head/drive pulley, tail pulley, and idler or takeup pulley.


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Re: Reducing Shaft Diameter Without a Lathe

Yeah, wheel. But in my world, a grooved pulley is a sheave, and a pulley is what we put on front and back of conveyors - but nobody seems to know that so its easier to call everything a pulley.

Re: Reducing Shaft Diameter Without a Lathe

You keep saying "pulley". Are you sure you don't mean "wheel"? With you design, there shouldn't be any need for a pulley and a drive wheel can be made from plywood stacked up to the needed thickness.

Re: Reducing Shaft Diameter Without a Lathe

Don't mind me.........my mind's turning to mush

Re: Reducing Shaft Diameter Without a Lathe

Good to know. I just learned how use it yesterday so errors were very possible on my part!

Re: Reducing Shaft Diameter Without a Lathe

I just now went out and grabbed one of mine, and the 3rd hashmark does peek out a bit when it's .003 shy. Probably about 25% of the hashmark.

Re: Reducing Shaft Diameter Without a Lathe

I think it's the perspective of the photo. That third hashmark after the 8 isn't quite fully exposed. If the thimble was turned another .003, then it would be reading the target of 0.875.

Either way, I'm not touching it any further until the pulley arrives next week.

I picked up a beautiful drop of 3/8" plate and some square tubing at the metal supply. Also a piece of masonite - this weekend I'm going to make a mockup so I can (hopefully) cut everything once.

Time to start a new thread!

Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by tapwelder

Looks like what he was aiming for. .875 and change? I don't own a micrometer and just lernt to read it this morning. But that us what it looks like to me?

The 3 hash marks to the right of .8 represent .075...............so, before reading the number on the barrel, we're already at .875 . Add the .022 on the barrel, and it brings us up to .897 .



This might help. It's not easy to learn to read these things, so mistakes are understandable. Not the end of the world.

If' you're just starting out using a mic, it's handy to keep a dial caliper nearby, and compare the reading you got on the mic with the reading you got on the dial caliper.

Some micrometers are confusing. The hash marks don't exactly correspond to the actual measurement. If there's any confusion.............take the mic off the workpiece, and rotate the barrel to the nearest hashmark, and see if the 0 lines up with it. I generally go down .025 to see if the 0 lines up.

In the case of the motor shaft: Turn the mic clockwise to see if the 0 lines up with the 3rd hash mark. If it does, you know that the .022 you read earlier,, is accurate. Also, you can turn back to .875, and see if the mic will slip over the shaft.

This is a common mistake, so like I said, it's no big deal if you verify your reading.

Re: Reducing Shaft Diameter Without a Lathe

Looks like what he was aiming for. .875 and change? I don't own a micrometer and just lernt to read it this morning. But that us what it looks like to me?

Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by Shootr

The emory just barely got away from me...

Attachment 1734245

But I like it!
Attachment 1734246

Looking at the mic...................this wasn't the final dimension was it? From here, it looks like .897

Re: Reducing Shaft Diameter Without a Lathe

I'm going to get flack for this one, but now that you've come this far and have declared yourself the competent backyard machinist, I have actually made a respectable keyway in a shaft with mini thin cut discs on a die grinder and a Dremel tool. It was for straight keystock... a half moon would definitely be more challenging. This goes back to my question on eccentricity and the need to center the pulley on the shaft with the key.

Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by Willie B

Actually, I've used a file on a shaft to fine tune the size. Sometimes, especially when everything is made in China, pulleys or couplings aren't exactly sized compatible. You must stroke with the file. Plumber's cloth is a better way, not as much chamfering the keyway. Method to be used only for cuts less than .001" deep.

As a former Machinist, I've used a file plenty of times to finish a shaft to close to final size then finish to size with roll cloth.

Re: Reducing Shaft Diameter Without a Lathe

That is great news!

Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by Willie B

Did it work?
a few thousandths can be tuned with bearing setter.

People avoid bearing setter, it requires heat to remove. None I've seen need over 400F to loosen. that isn't enough to harm any metal I know of.

Yes, I think extremely well. I was shooting for 0.876 +/-. I got too happy with the final emery cloth and it's at 0.872 in the center. Each end is 0.873. Used a flap wheel to get close, then heaven knows how many feet of emery to finish it to 150 grit.

Re: Reducing Shaft Diameter Without a Lathe

Did it work?
a few thousandths can be tuned with bearing setter.

People avoid bearing setter, it requires heat to remove. None I've seen need over 400F to loosen. that isn't enough to harm any metal I know of.

Re: Reducing Shaft Diameter Without a Lathe

I am reminded of the saying:
"Anything seems possible when you don't know what you're doing."

Get the right size pulleys or bore them to proper size.

Re: Reducing Shaft Diameter Without a Lathe

The emory just barely got away from me...

Attachment 1734245

But I like it!
Attachment 1734246

Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by CAVEMANN

If that motor shaft has a key way then it will be impossible to keep it round with your method, 3600 RPM will smoke a file really quick if you're not careful, although at that diameter the surface speed won't be horrible. I wouldn't worry about disassembling the motor, they're pretty simple. Take it apart & take it to a machine shop where they can put the shaft on centers & drive it with a lathe dog, you will be much happier in the end. What MJD said about the file & the keyway IS spot on.

Actually, I've used a file on a shaft to fine tune the size. Sometimes, especially when everything is made in China, pulleys or couplings aren't exactly sized compatible. You must stroke with the file. Plumber's cloth is a better way, not as much chamfering the keyway. Method to be used only for cuts less than .001" deep.

Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by whtbaron

Like Willie, I've used files and looped coarse emery cloth to peel down smooth shafts a little... but almost 1/8" is a lot of metal.

Any of you machinist types answer my question about the keyed pullies? Is the hole off-center to allow it to center as the key is driven in?

The hole in pulleys is bored concentric with the outside of the pulley. It is the shaft that holds the pulley where it needs to be. As long as the bore is in spec the pulley will be too. I've seen lots of farm machinery that the fits were made with wet paint.
This project is a belt sander. Nothing critical there and again, for those describing machining over a keyway problems, this motor shaft has no keyway.

Re: Reducing Shaft Diameter Without a Lathe

Also, give the small amount of removal, I think concentricity error potential will be less an issue, than making sure it spins literally. That error will transfer more readily, if the pulley does not rest properly on the journal.

Re: Reducing Shaft Diameter Without a Lathe

How can a weldor mess up a steel shaft? If taking off <1/16"(sounds better than 1/8 total) is not successful, then take it apart, build it up then take it to a machine shop and act like you have no idea how it how in thay condition. Then tell them, you will send all your machine work to them.

That looks like a decent motor. I would not hesitate on some of the motor i have had in my jet bandsaw or drill press, since a new motor would be an upgrade.

It looks like a direct drive lathe to me, just need some solid mounting and solid rests.

Be safe.

Re: Reducing Shaft Diameter Without a Lathe

I always bore center for a pulley. But I asked about a mill, how good is the drill presss... after that call your local machine shop. 1/8 inch you lose at least half of a keyway. I may have more resources than most, but if you were to remove the keyway completely than I would see if you could fine BK#7 bushing cement. It rusts aluminum and steel. In 20 minutes you will break everything but that bond. But it hasn't been made in years (20 +).

I have several kits, which I inherited. I also have multiple lathes and mills at my disposal.

A simple bore job with keyway shouldn't be excessive on the pulley. The keyway can be cut with a carbide burr and a "dotco" for what it's worth.

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Re: Reducing Shaft Diameter Without a Lathe

Originally Posted by whtbaron

I think he said that the keyways are all in the pulleys, none on the shaft. That brings up another question in my mind... are those pulleys milled slightly off center to center them as the key way is tightened?

Originally Posted by whtbaron

Like Willie, I've used files and looped coarse emery cloth to peel down smooth shafts a little... but almost 1/8" is a lot of metal.

Any of you machinist types answer my question about the keyed pullies? Is the hole off-center to allow it to center as the key is driven in?

I'm not aware of any being off center. If you want concentricity and no worries about pulleys coming loose, a taper lock or a Q style bushing and a hubbed pulley or sprocket is the way to go.

Re: Reducing Shaft Diameter Without a Lathe

Like Willie, I've used files and looped coarse emery cloth to peel down smooth shafts a little... but almost 1/8" is a lot of metal.

Any of you machinist types answer my question about the keyed pullies? Is the hole off-center to allow it to center as the key is driven in?