Rebuild work ? 2 questions.

[AJ]

There is rebuilding, refurbishing and cleanup.

One must understand what the end result will be with each option to consider return on investment.

A South Bend with worn ways will be different than one without but consider the real difference in cut.

Cutting at center and lowering tool as a worn way and the difference in depth of cut is minimal.

Rigidity and other features of any lathe when new limit how good it can be.

Lipstick on a pig is a good line here.

A worn but cleaned up South Bend works almost as good as the exact same machine when new in proper hands.

It may be better to tear down and clean all then paint and tune to adjust ships and gibs.

The money saved can be used for tooling or put aside for the next machine...and there will be...on lathe 9 or so and was not even looking for last one...

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Is there a way to give me a little more insight as to what you mean ? My primary use will be gunsmithing. So let`s say I have a Rem700 1" dia. bull barrel I need to thread for a compensator(last 1/2" of barrel). I have 8" sticking out of the chuck and 16" in the spindle being supported by a spider. I`m also using a steady rest because I`m way past my 2x dia............. Because of one reason or another that is the only way to place the work in the machine. At that same point is heavy wear in the bed and the carriage drops A LOT(.125). What would I do to compensate for that drop in the bed ? All hypothetical of course but could easily be a real world scenario..My threads would destroyed no ? If I tighten the gibs I can`t move the carriage back for the next pass. I`m so new to this that I don`t even know how far off I am in this scenario ? LOL....What do I do ?? I`m trying to get a visual as to what you could do ? Thanks, AJ

 

[projectnut]

Things can get a little complicated. I have an older machine that has the ways worn almost .015" near the headstock. The first 18" are worn down because that's where most of the work was done. the remaining 3 1/2 feet of the bed is not worn. I can position the tooling and cut accurately at either end of the bed, but the problem comes in when having to make a cut through the transition area. The tool slowly rises and will take a smaller cut nearer the tailstock than it does on the headstock end. About the only way to compensate is reposition the work piece so that all the cutting is done either on the worn section, or on the un worn section. In the past I've done the cutting on the un worn tailstock end. That requires the work piece to be flipped end for end in the chuck and reindicated. It's a PIA but can be done.

 

[AJ]

Things can get a little complicated. I have an older machine that has the ways worn almost .015" near the headstock. The first 18" are worn down because that's where most of the work was done. the remaining 3 1/2 feet of the bed is not worn. I can position the tooling and cut accurately at either end of the bed, but the problem comes in when having to make a cut through the transition area. The tool slowly rises and will take a smaller cut nearer the tailstock than it does on the headstock end. About the only way to compensate is reposition the work piece so that all the cutting is done either on the worn section, or on the un worn section. In the past I've done the cutting on the un worn tailstock end. That requires the work piece to be flipped end for end in the chuck and reindicated. It's a PIA but can be done.

Thanks...Ok, I had a feeling it was a little more involved then my skills can handle right now..lol I think my OCD would go into overdrive....When I first setup my 10k I was test cutting a 0.020 taper in 8". I talked to my dad about it and he gave me a few pointers about setting up and shimming. He said with a older, smaller benchtop I should be happy if I could get it within 0.001-0.003. I said "1-3 thou, no way ! My OCD can`t handle that"..lol I ripped everything apart and started my setup from scratch after a few failed re-setup attempts that put the taper at 0.060. I thought to myself "I need things tighter or I need a new machine !". Yeah, that`s how bad it is if you`re living in my head. I spent 3 days, a sleepless night and the neighbors knowing the extent of my Marine Corps like vocabulary but I had to have it better..These pics are the result.....That`s over about 7"...and yes it mics the same, just at 0.6222....It does this consistently. My OCD is at bay. This is what happens when you grow up with a Machinist who is in charge of the Seawolf project ! lol

 

[tq60]

Is the work supported by tail stock?

Is tail stock aligned?

Unsupported material will flex too.

Your tapers are way big...

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[AJ]

Is the work supported by tail stock?

Is tail stock aligned?

Unsupported material will flex too.

Your tapers are way big...

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Were you able to see my whole post and pics ? I see you`re on your phone maybe it did`t show....0.0000" taper after A LOT of screaming special magical words..Very happy with the repeatable outcome..Maybe my explanation of the pic is a little ascue ? It` shows 0.6455 on both ends with calipers and 0.622 when done with the mic on both ends. Mics being more accurate and all.

 

[pacifica]

Things can get a little complicated. I have an older machine that has the ways worn almost .015" near the headstock. The first 18" are worn down because that's where most of the work was done. the remaining 3 1/2 feet of the bed is not worn. I can position the tooling and cut accurately at either end of the bed, but the problem comes in when having to make a cut through the transition area. The tool slowly rises and will take a smaller cut nearer the tailstock than it does on the headstock end. About the only way to compensate is reposition the work piece so that all the cutting is done either on the worn section, or on the un worn section. In the past I've done the cutting on the un worn tailstock end. That requires the work piece to be flipped end for end in the chuck and reindicated. It's a PIA but can be done.

Another way to compensate for taper is to use the compound and shift it a degree or less. Helps to use a sine bar. I have done this and got rid of taper(within .0002) due to a worn bed ; limited by the movement of the compound, in this case 4".

 

[AJ]

Another way to compensate for taper is to use the compound and shift it a degree or less. Helps to use a sine bar. I have done this and got rid of taper(within .0002) due to a worn bed ; limited by the movement of the compound, in this case 4".

I`ve read about that method. I need to try it..I wish I had more time in the shop under a good old timer. Those guys have such a wealth of knowledge..