Summit 14x40 tailstock center high .020

apestate · Jan 6, 2006

Hey guys

I am stumped here. I'm trying to do some simple work with a Summit lathe and I found that the tailstock center is high .020"

So, I slid it off and lightly stoned the ways to make sure it wasn't just bunged up, that looked pretty good. Then I put it back on and checked out the sliding action of the ram. It's straight. There isn't play in the ram either.

So now I'm looking at the damn thing and wondering if it's the wrong tailstock or something?? It's a Summit 14x40B.

The only other thing to do is try to separate where it adjusts for windage and see if there's some build up in there, but I don't see a gap of 20 thousandsths~!

What the hell is going on here, any suggestions?

-Erik

Kurt Westfall · Jan 6, 2006

Clamped down? They will lose some height when you clamp them down, but I don't they will lose no .020 There made that way for wear, so I was tolled by my old mentor.

apestate · Jan 6, 2006

yea, clamped or unclamped.

the tailstock on this machine is basically useless.

I don't doubt that it is the original tailstock, I just think some jackanapes picked up the lathe with a forklift in the middle of the bed.

Here's a Summit photo of the machine I'm talking about. http://www.summitmt.com/products/14series.shtml

If you notice, that blue sheetmetal in the front is just a cover. There's nothing that supports the bed in the middle and I guarantee some BODY picked it UP there.

I don't know if that's the issue or what. The damn thing is jacked up in the back about half an inch. It's sitting on 4 rubber pads at the extreme corners and it isn't level this way or that.

I'm putting it back together and answering all questions people ask me with, "beer?"

"Beer? Are you beer? Not interested."

Gary E · Jan 6, 2006

Do you have a alignment test bar for the headstock spindle? If so use it to make sure the headstock is correctly aligned to the bedways... untill that is proven correct, do nothing with the tailstock.

apestate · Jan 6, 2006

no test bar

I don't even know what one looks like. is it possible to make one?

What about boring jaws and then chucking a straight piece of ground & polished?

apestate · Jan 6, 2006

I've made a test bar for between centers, but all I've ever done to mess with headstock alignment is turn a large diameter bar 3 or 4 inches in length and adjust based on that.

I know the lathe will cut a taper of .0005 in 3" with that kind of test.

It's basically all cranked out of shape, but it would be worth fixing it. another day.

mitchell · Jan 6, 2006

Well I doubt tha picking the lathe up with a fork lift in the middle will phase this lathe at all .Maybe if you let hang by the middle for a few years but not by moving it. You first need to see if the tail stock ram is parallel to the bed. If it is and your tails stock is truly up .020 the it is not the one that was scraped in for that lathe ( or a victom of bad QC). This is not that uncommon. And it is unlikely that there is something like a burr between the base and body of tail stock but check anyhow . If every thing checks fine if it where my lathe I would simple pull the base of tail stock and remill where tail stock and base join maybe leave a .001 or alittle aound there to compinsate for future wear.

Mike C. · Jan 6, 2006

If the bed is bent, you will find the tailstock to measure to different heights as you travel down the bed. If it is consistently .020 high, it's definitely in the tailstock.

I'd chuck up a long bar between centers and take a few light cuts, adjusting the tailstock offset to get it to 0* taper as measured at points a few inches bewteen along the entire length with a vernier mic. Note if the tailstock has to be offset noticeably from the factory-marked center to achieve this.

Sounds like just a bad apple to me, though.

Gary E · Jan 7, 2006

atetsade,

Without a test bar there is little you can do unless you have other test equipment.

The bar has the same taper of the internal taper of the machines spindle and a straight dia of 1.500 probably about 18 in long. If you bought the machine new or from a dealer, they may have one you can borrow.

Boring jaws and chucking a straight bar will not be good enough.

I doubt very much that the bed is bent. Lathes are picked up with forklifts all the time.

Does this lathe have 2 flat ways? If it has a flat way both front and back you could turn a short bar the EXACT DIA of the tailstock quil. Now you will need a parallel and a height gage and indicator. Set the parallel on gage blocks so it is above the V ways. Use the height gage and indicator to measure over the top of the part you just turned and set the indicator to ZERO. Slide the parallel and height gage to the tailstock and see if it's the same height.

This still does not tell you that the machines spindle is or is not parallel to the bed ways, that's why you need a test bar.

apestate · Jan 7, 2006

yea that would be a nice test bar but unfortunately I have never seen one.

The bed is LeBlond profile.

I don't get it. How the hell can the tailstock be .020 high on center? That doesn't make sense even if it WAS a different machine's tailstock. That doesn't make sense even if we made it ourselves.

There has to be something extremely wrong with this setup.

Gary E · Jan 7, 2006

Let me ask you how do you know it's .020 higher than the headstock?
Tell me exactly how you checked it?

I know the LeBlond has a front way on an angle, but this old guy has CRS sometimes and dont remember zactly what the other ways look like so tell me from the front way I will call "sloped" to the one farthest from the operators position what they look like. Maybe we can figger out a method to help you.

Any idea whan this was built?

Ok.. so it's a Summit... not a LeBlond so it maters not one bit when it was built... but still I need a description of the way system.

quasi · Jan 7, 2006

Are you sure the dealer didn't get a couple of tailstocks interchanged?
I saw this happen with a bunch of school surplus, Standard Modern lathes a fellow sold around here. He was phoning customers and moving tailstocks between them for quite a while!

Asquith · Jan 7, 2006

Presumably you checked with a clock fixed to the chuck and rotated round the tailstock barrel or round a center in the tailstock? Presumably also the clock's bracket was stiff and not at all droopy?

If the tailstock is high because the bed is warped (hogging or sagging), then if you have a precision spirit level, put it on the ways at various places along the length, and check that the level reads the same at all positions.

3t3d · Jan 7, 2006

Presumably you checked with a clock fixed to the chuck and rotated round the tailstock barrel or round a center in the tailstock? Presumably also the clock's bracket was stiff and not at all droopy?

Magnetic base "droop" will make it read as if the tailstock is high.
Someone on another forum just recently discovered this annoying "phenomenon"

Try pushing on the indicator base rod, to test it's stiffness.
Pete

Forrest Addy · Jan 7, 2006

Make sure th undicator set-up you used to dial in the quill is rigid. Horizontal trams are notorious sources of alignment error.

Limber dick 5/16" rods and snugs can droop an amazing amount and when you tram in horizontally the droop doubles. Weld a short chunk of suitable dial size indicator rod to a hunk of 2" pipe long enough to span the carriage. Chuck the pipe and clamp the dial test indicator on the stub.

Use a piece of 2 Lb test fishline looped under the indicator to test the rigidity of the set up. Loop it under the indicator body as close to the pivot as you can get. Lift gently and note the indicator's deflecion. A clever guy will build a fish line and pencil balance to detect/eliminate droop error.

apestate · Jan 7, 2006

yea.. it's a noga base

no time to write but I will say that I did indicate the center. I know it's way off too because it centers for ****.

TheMetalDoctor · Jan 8, 2006

Erik,

Measure the distance from the tailstock center to the bed, compare that to the distance from the headstock center to the bed. These two numbers should be the same. If you are .020 long on the tailstock end, sounds to me like you have the wrong tailstock.

TMD

apestate · Jan 9, 2006

aha

that's a lot of good information.

I've read it all twice and I'm trying to absorb it all.

I still have a feeling it is the wrong tailstock. Once I get the machine leveled out I'll take more scientific measurements.

This is the only operating conventional lathe in the machine shop and I always end up reworking stuff on it. It sucks not to have the tailstock ready!!!

Ok, thanks again. They do have this nice magnet chuck that remounts within .0002 axial runout. That has been the greatest aid to these horrible little jobs the lathe keeps getting piled full of.

Summit 14x40 tailstock center high .020

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