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  #11  
Old 10-21-2021, 07:44 AM
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Originally Posted by OldRedFord View Post
I did check run out at the steady rest and I've only got .002".

I did not check at the chuck but I know that three jaw chuck has about .030" run out.

I think I should put the 4 jaw back on.
I think you should set up a "poor mans run true" on your 3 jaw to correct that runout issue.
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Last edited by Ironman; 10-21-2021 at 09:39 AM.
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  #12  
Old 10-21-2021, 09:59 AM
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I think you should set up a "poor mans run true" on your 3 jaw to correct that runout issue.
I did what Gerry said a few years ago. Gets all the run out down to a thou or less. Have to reset it about twice a year. Video.
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  #13  
Old 10-21-2021, 09:40 PM
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I put the 4 jaw back on the lathe. Seated the bar into the bore of the chuck and got it indicated in to .002 inch.

I then set the steady rest right in front of the chuck and adjusted the rollers to the point the bottom two just touched. Closed the top of the steady rest and adjusted the top roller. Opened the top on the rest and slid it into position and locked everything down.

Checked run out at steady rest and had .003 inch.

Fired up the lathe at about 350ish rpm and everything looks good. Tried top speed of 700 rpm but the rollers in the steady sound like it's too fast. Probably a little sore out.

I think I'm good to go.

Spindle bore is 1 3/4" iirc
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  #14  
Old 10-22-2021, 10:39 AM
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Going to face off the end and drill a center and use the tail stock live center to do your machining?
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  #15  
Old 10-23-2021, 11:19 AM
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Timmy the dumb fuck is at it again...

Read what Keith wrote, very rarely should run a steady on the mill surface. Mill stock is not round concentric or straight.

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Originally Posted by LKeithR View Post
Put the bar in the chuck, slide it in till there's only a couple inches sticking out then face it off and drill a centre hole. Once you've drilled it, slide it out as far as you need it and run the tailstock centre in to support the outboard end. Once you've done that machine a narrow strip where you want the steady to run, then set up the steady so it's just snug where it's running on the shaft. If at all possible try to use the live centre for as much of the process as you can and it's generally a good idea to run a bit slower RPM if you can get away with it.

When using a steady the area where you run it needs to be round and concentric to the centreline of the workpiece. This applies to any steady rest but it's especially important if you're running a roller bearing steady. I have found the latter to be quite unforgiving when it comes to alignment of the workpiece. I would try and find a steady that uses brass or bronze for the bearing surface.

I'm pretty sure this will fix your problem; if it doesn't then you've got some misalignment somewhere. Those rollers only need to be cocked a little bit to suck the material out of the jaws...
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Originally Posted by OldRedFord View Post
I put the 4 jaw back on the lathe. Seated the bar into the bore of the chuck and got it indicated in to .002 inch.

Checked run out at steady rest and had .003 inch.
Wow, you still have A LOT of run out. You should have and extra zero in those numbers.
There is less run out in a Filipino Whore after the fleet sets sail.
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  #16  
Old 10-23-2021, 11:21 AM
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Oh and clean that lathe up, it looks shitty and rusty.
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  #17  
Old 10-23-2021, 12:54 PM
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Oh and clean that lathe up, it looks shitty and rusty.
You beat me to it.
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  #18  
Old 10-23-2021, 01:07 PM
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Quote:
Originally Posted by Shade Tree Welder View Post
...very rarely should run a steady on the mill surface. Mill stock is not round concentric or straight...
Yeah, I didn't emphasize that point. You might get away with it if you're working on turned and ground shafting but otherwise it's just going to fight you. Normally, the only reason to use a steady is if you need to work on the end of the stock or if you need to keep a long, thin piece of material from whipping in the centre. In any case you should always start by drilling a centre hole in the end and then machining a steady band and mounting the steady.

By performing the operations in this order you establish an imaginary centre-line through the workpiece from the chuck to the tailstock centre. Unless you want to utilize some portion of the original OD of the material it doesn't matter at this stage if you have a bit of runout. Once you start machining all the surfaces that get turned are going to run concentric to that imaginary centre-line.

This is why you can machine all the features on a workpiece and have everything running true even if your chuck has some runout. It's only if you have to flip a part in the chuck (to work on the opposite end) that you need to be concerned with the runout of your chuck.

Once you've done all the machining on the OD of the part you can set up your steady if you need to perform drilling or boring operations on the end. If you have machined surfaces on the OD of the stock you can run the steady there or you can cut a steady band just for that purpose. You would try to place the steady a lot closer to the end of the workpiece than Tim has in his pictures...
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  #19  
Old 10-24-2021, 11:23 AM
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Quote:
Originally Posted by LKeithR View Post
Yeah, I didn't emphasize that point. You might get away with it if you're working on turned and ground shafting but otherwise it's just going to fight you. Normally, the only reason to use a steady is if you need to work on the end of the stock or if you need to keep a long, thin piece of material from whipping in the centre. In any case you should always start by drilling a centre hole in the end and then machining a steady band and mounting the steady.

By performing the operations in this order you establish an imaginary centre-line through the workpiece from the chuck to the tailstock centre. Unless you want to utilize some portion of the original OD of the material it doesn't matter at this stage if you have a bit of runout. Once you start machining all the surfaces that get turned are going to run concentric to that imaginary centre-line.

This is why you can machine all the features on a workpiece and have everything running true even if your chuck has some runout. It's only if you have to flip a part in the chuck (to work on the opposite end) that you need to be concerned with the runout of your chuck.

Once you've done all the machining on the OD of the part you can set up your steady if you need to perform drilling or boring operations on the end. If you have machined surfaces on the OD of the stock you can run the steady there or you can cut a steady band just for that purpose. You would try to place the steady a lot closer to the end of the workpiece than Tim has in his pictures...

Or run a cat’s head on the part. Don’t have a pic but should show up with a little digging.


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  #20  
Old 10-29-2021, 11:05 AM
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Some progress. Punch fits nicely in the bore.

Lathe isn't rusty, camera makes it look bad.
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