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J Tiers
02-23-2008, 12:10 PM
The recent work I did with tailstock fixtures brought out the tailstock wear problems I have. The ram is not worn more than a half thou, but the CI bore of the T/S is bell-mouthed. Probably about 15 thou all around, somewhat "egged" in "up and back" direction.

Really came out when grinding the blank arbors to correct taper. I noticed the shift when clamping, and the looseness if not clamped. When sticking out enough to clear the grinder (1.75 inches), moved about 40 thou at outer end!

This is a Logan. I asked on the Logan email list , but was basically berated by Scott L for not wishing to buy a new TS casting for $700........ yea, I am a little sensitive, but so are a number of you folks, so...... Anyhow, no help there, I'm done with them.

So I have some wear to deal with, and dunno the best approach.

An oversized ram would be good. I suggested that to Scott Logan as a replacement part he could sell, but he doesn't like it. I'd have to make it, and the ram I have is really fine.

Sleeving is another way, but the casting would have less than 1/4" left if I bored it out for a 1/8" sleeve. What looks like a lot of CI is actually only around 0.3", so there would be 0.300 - 1.25 or 0.175 thickness left....... not good. A steel sleeve could be thinner, but might be not so good, and CI would need at least the 1/8". I don't like the thinning of the casting that would result.

A tapered front bearing would work, be adjustable for future wear, and similar to larger machines, but there is no "nose" to mount it to. They are typically adjusted by screw collars, and that is a bit hard to attach. See pics.

Any other ideas?

http://img.photobucket.com/albums/0803/jstanley/TS1.jpg

http://img.photobucket.com/albums/0803/jstanley/TS2.jpg

SGW
02-23-2008, 12:20 PM
You'd need to bore it out too much to put in a sleeve to accept the standard tailstock barrel; could you just clean it up to parallel, put in a sleeve with a smaller i.d., and use a smaller-diameter tailstock barrel? (Might end up being too small, but it's a different way of looking at it.)

Carld
02-23-2008, 12:27 PM
It seems counter productive for Scott to belittle your questions, he is after all selling parts isn't he? Seems to be a mistake for a person in business to do that as I see it.

If your quill is in good condition have you considered setting up the tailstock in a mill to bore it. Then taking a light cut through the bore and coating it with Devcon plastic steel and reboring it to size.

It would last a long time and could easily be replaced again when needed.

On the other hand you really don't need a 1/8" thick sleeve, a 1/16" thick sleeve to a slip fit and locktited in place and finish bored to size would work.

Quote "The egg shaped hole was to the top and the rear". That's why most lathes have the quill lock on the rear of the tailstock by the mouth of the bore. Appearantly someone didn't use the quill lock very much when turning between centers on your lathe.

SGW
02-23-2008, 12:28 PM
What about that Moglice stuff used for building up ways, that has been discussed in the past?

Carld
02-23-2008, 12:37 PM
Very expensive.

BigBoy1
02-23-2008, 12:38 PM
I don't know if it be practical, but could you swap tailstocks with some other machine? I don't know how interchangeable tailstocks are between different makers of machines, but there just might be one that would "fit" your machine. Just a thought.

Bill

John Stevenson
02-23-2008, 12:44 PM
What is the diameter of the tailstock ram ?

.

uute
02-23-2008, 12:46 PM
Could you make a bronze liner thinner, or would you just be loosing the durability & hardness of CI?

uute

J Tiers
02-23-2008, 01:18 PM
What is the diameter of the tailstock ram ?

.
1.125" now -.0005

John Stevenson
02-23-2008, 01:31 PM
What about making an angled bracket up to hold a bearing at center hight, move the T/S in front of the saddle, nip it down and with a boring bar in the chuck and supported in the bearing take the T/S bore out 56 thou and make a new barrel out of a length of 30mm silver steel or drill rod ?

You can use the saddle to push the T/S along the bed for a feed .
It can also give you the chance to make other mods if needed like converting to rack feed.

I need to convert my TOS to rack feed as it's such a pain winding in and out all the while.
If you have ever used a lathe with rack T/S feed you always miss it.

.

JCHannum
02-23-2008, 01:34 PM
I have run across Scott Logan a couple of times. I think he might be related to the Milacron guy.

There have been several posts here and on PM recommmending hard chroming the ram as one fix. That would make it oversize and the tailstock can be bored to fit. It is not too difficult to line bore the TS, admittedly trying to do it to tenths is difficult.

Question is, is any gain worth the trouble? If you are looking for total, dead nuts accuracy of the tailstock, you will have to do significant rebuilding and scraping of the base to get it right and even then, it is still a tailstock.

TGTool
02-23-2008, 02:08 PM
A sleeve wouldn't have to be full length. I presume most of the wear is the front end where the side force is applied. What about a bush about 1/2" long or whatever looks reasonable? The quill would have guidance and support front and back and is probably stiff enough to stand up. Long extensions and a loose fit with the tailstock screw would compromise positioning but it's an easy fix for an 80 percent solution.

Jan

quasi
02-23-2008, 02:19 PM
Plaza machinery has some Logan parts I believe. Or buy a parts machine, or wait for a tailstock on Ebay. $700.00 would buy the average Logan on Ebay, they don't seem to have the cult status of Southbend.

pntrbl
02-23-2008, 02:51 PM
I'm on the same Logan/Yahoo group that Jerry contacted Scott on and I agree. Scott was outa line. There's no economic sense to spending more than the value of the machine for a repair part. I dunno why Scott even brought it up.

SP

J Tiers
02-23-2008, 03:48 PM
TGTool has an obvious solution......the problem is at the front, so fix the front.

I give that an A+ and a thank you!

Scott is similar to Milacron, but then so am I to a degree. People like us don't mix well together, I guess.

lazlo
02-23-2008, 04:22 PM
There have been several posts here and on PM recommmending hard chroming the ram as one fix. That would make it oversize and the tailstock can be bored to fit.

The problem I see with hard chrome is that it's electrolytic, and therefore doesn't plate evenly, so you'd have to sent it out to a grind shop afterwards to get a uniform and concentric OD. Between the hard chrome and the grinding, you're talking $200 - $300.

Bushing the end of the ram socket seems like a kludge, but if it works...

If it were mine, I'd bore the tailstock and make a new ram out of 4140 Pre Hard.

jimsehr
02-23-2008, 05:07 PM
How about boring out the ram to 1 inch and pressing a solid Morse taper socket 1 inch x 4 inch long in. Part costs $14.42 @ Enco and if that od is too big grind it down to where it will work. If you have to pin or silver solder it in
place. Or if you want a soft body look at their 2 mt extension socket where the body is soft and tang hard. Cut off tang and you are good to go. $10.96
Jim

http://i86.photobucket.com/albums/k106/jims_03/IMG_0023.jpg

lazlo
02-23-2008, 05:29 PM
That's a good idea Jim -- if I were going to sleeve it, I'd want to sleeve the whole taper socket, and not just the end.

But the tailstock ram is probably worn too. Is the ram on the little Logans hardened?

GKman
02-23-2008, 05:30 PM
Isn't that the kind of wear that old timers were always fixing with babbitt with the shaft in place? Where are the old railroaders this afternoon?

John Stevenson
02-23-2008, 05:31 PM
I think JT is talking about sleeving the bore of the T/S as he has said the barrel is only 1/2 a thou down.

So any work sleeving the ram is wasted.

.

Carld
02-23-2008, 05:33 PM
Jim, it's not the socket that's bad, it's the bore of the tailstock casting.

JCHannum
02-23-2008, 05:54 PM
The problem I see with hard chrome is that it's electrolytic, and therefore doesn't plate evenly, so you'd have to sent it out to a grind shop afterwards to get a uniform and concentric OD. Between the hard chrome and the grinding, you're talking $200 - $300.

Bushing the end of the ram socket seems like a kludge, but if it works...

If it were mine, I'd bore the tailstock and make a new ram out of 4140 Pre Hard.
This is one of the threads I was remembering;

http://bbs.homeshopmachinist.net/showthread.php?t=18167&highlight=hard+chrome

Hard chrome can be applied with reasonable accuracy and selectively if neccesary. It would be a suitable repair for this, but Jan's suggestion is probably the most sensible at this point.

Bob Ford
02-23-2008, 06:42 PM
Use John's suggestion to bore TS. Use the boring head from your mill. Your lath chuck jaws should fit between the R8 taper and the rear ground diameter. This gives you the use of the .001 dial on the boring head.

Bob

Your Old Dog
02-23-2008, 06:55 PM
check you private message folder...

J Tiers
02-23-2008, 07:33 PM
The other issue with sleeving and/or oversizing is obvious when the ram is out...... The lock intersection with the bore is a problem to machine..... it would have to be cut in the sleeve, without damaging the existing lock recess in the casting. Do-able, but not ideal.

I have a boring head, but mine is for smaller diameters. I'll have to check it's max diameter.

I'm not so convinced a partial bore is a "kludge"...... seems like it retains the good part and fixes the problem.

Is there a reason to think it is a bad idea?

lazlo
02-23-2008, 07:50 PM
Hard chrome can be applied with reasonable accuracy and selectively if neccesary.

The problem with hard chrome is that the thickness of the coating varies according the distance to the electrode. So the thickness spec is pretty loose:

This is from a plating shop that does hard chrome:

http://www.electro-coatings.com/nyechrome.html

CHROME PLATING IRREGULAR GEOMETRIC SURFACES

During electrodeposition, the current distribution over different areas of a component greatly varies, depending upon its geometrical shape. Elevations and peaks, as well as areas directly facing the anodes, receive a higher current density than depressions, recesses and areas away from or not directly facing anodes. The variation in current density over different areas produces a corresponding variation in the thickness of the deposited metal.

So after you lay down the hard chrome, you'll have to send the part out for grinding.

This is one of the reasons electroless nickel is becoming so popular -- the chemical deposition makes a much more uniform thickness, even in inside features, down holes, etc. But even for EN, the plating shop will only guarantee a thickness of +/- 5 tenths over 6 inches or so.

As far as the costs quoted in that thread, I got a similar quote: .50 - .75 per square inch for Hard Chrome or Electroless Nickel. But most plating shops have a minimum of $100 - $175.

I've been looking into Hard Chrome, Electroless Nickel et al recently because I want to have the hubs on my Vari-Seed pulleys plated.

lazlo
02-23-2008, 08:06 PM
The lock intersection with the bore is a problem to machine..... it would have to be cut in the sleeve, without damaging the existing lock recess in the casting.
...
Is there a reason to think it is a bad idea?

That's why I'm not sure that sleeving the worn part is a good idea. You say:


The ram is not worn more than a half thou, but the CI bore of the T/S is bell-mouthed. Probably about 15 thou all around, somewhat "egged" in "up and back" direction.

So you'd have to bore part of the tailstock socket, fit a partial sleeve, fix it in place somehow (a shrink fit or a key of some sort) then re-bore so you have a smooth interface between the old socket and the new sleeve.

Then you'd have to turn-off the half-thou bell-mouth of the ram, sleeve that, fix it in place somehow, and re-machine smooth across the interface between the partial sleeve and the unworn part of the ram.

Seems like it'd be a lot simpler to turn the ram straight, re-bore the tailstock, and shrink-fit a full sleeve.

J Tiers
02-23-2008, 09:06 PM
The ram isn't belled......

The bore of the T/S is.

I was going to "hang" the 1/2 thou undersize...... This IS a tailstock..... I just don't want it to be THAT loose... the lock tends to shove it about 20 thou to the side, but that actually seems to be the max 'outness" with ram extended. LOOKS like 40 thou, but seems to be about 20. Just enough to cause troubles.

Due to the belling, the lock does not hold it entirely steady, nor does it go back to the same place repeatably. Plays heck with grinding tapers on short things, just allows "rings" on longer things where teh angle isn't so acute.

If I bore the whole thing for a larger ram, the ram will be non-standard forever. Unless I sleeve it with a very thin sleeve. A thick sleeve won't fit without cutting too much casting away, IMO.

A part sleeve would be easier to do, and probably more effective. The wear is at the front, the fix at the front, easily renewable in future if needed. That avoids the lock area altogether.

Turn the sleeve? Yeah between centers on my other lathe...... wait, I DO have one, it's a Boley..... might be a tad small, but...... well OK, nope, don't have one.

Grinder needs parts....... and that is a grinder job anyhow. Lathes (especially Logans) are for getting it close enough to send to the grinder.

darryl
02-23-2008, 09:36 PM
Seems to me that boring the tailstock for a short distance, then inserting a turned and bored bush is what I'd do- assuming the ram is not tapered or out of round.

I don't know the Logan lathe, so this is just an idea- can you use the undamaged end of the bore in the tailstock to guide a cutter? This would require having or making a bar with a cross hole to hold a cutter into, then a bushing in the right end of the bore to guide that end of the bar. As John said, use the carriage to push or pull the tailstock along to make the cut. The adjustment of the cutter shouldn't be critical since you'll want to turn the bush after the boring is done anyway. This method might yield a bore that's more aligned with the headstock, and should allow the ram to have a good range of motion without wandering off axis too far.

Oldbrock
02-23-2008, 09:53 PM
If it was my lathe I would follow Darryl's advice. Make a concentric bronze bushing for the right end and use a boring bar with tool hole near the chuck end. I'd probably bore in about 1" and shrink a sleeve in. Bore the sleeve to size and after it's shrunk (about .001 tight) it should be honed to size. If no one in your area has a sunnen hone, use a brake cylinder hone to get enough clearance. You could try boring out the last thou or so but honing has more control. Good luck, Peter

lazlo
02-23-2008, 09:56 PM
Bore the sleeve to size and after it's shrunk (about .001 tight) it should be honed to size.

That's what I meant about the hard part of the partial sleeve: getting the interface between the sleeve and the unbored tailstock smooth.

J Tiers
02-23-2008, 10:44 PM
Doesn't have to be smooth.

DOES have to be "on-size".

A bit of a step, if the boring didn't go totally past the belling, wouldn't hurt a bit, as I see it.

I need to survey the hole and check the sizing in a ways...... the lock and the anti-rotation key make that a bit more trouble.

But it seems that if the outer end of the hole is "on", and the part back inthere is OK, it will be fine....

Added..... sintered bronze, as I think is suggested below, sounds like it might not be good..... that stuff squishes. Solid bronze would be OK. CI would be OK but brittle, steel might be OK, I don't see it galling at the very slow speed of movement, but might wear the ram..

pcarpenter
02-23-2008, 10:57 PM
TGTool beat me to it. I was going to suggest a standard bronze bushing in the closest available size, with a relief bored (using a boring head in the spindle for correct alignment) to house it. Once pressed in place, it could then be bored to diameter in the same way.

If you used a flanged bushing, you would have something to get hold of when (if) you need to just pop it out for future replacement.

Paul

steam4iam
02-24-2008, 01:13 AM
G'day

A quick and dirty method might be to make up a front piece to bolt and stud on to the front of the tailstock. It only need be 1/2" to 12mm thick bored for an exact fit around your quill. You could argue that you would loose that amount of quill travel but my guess is that you seldom start with the quill wound right back. This method needs no boring and only requires drilling and tapping three holes in the front face of the tailstock. It may pay to face the front to make it true, this could easily be done with a tool in the 4 jaw chuck.

To ensure centering of the new nose I would drill radial holes into the retaining screw holes in the nose, tap these radial holes and put set/grub screws in them the bear on thin sleeves on the retaining screws. The retaing screws would be just nipped firm and the final centering made by adjusting the radial set screws before nipping the retainers right up.

One good turn deserves another

Regards
Ian

John Stevenson
02-24-2008, 05:31 AM
Saw 4 radial slots into the end of the tailstock with a hacksaw and fit a worm drive hose clip over them.
That way it's adjustable for future wear. :p

.


.

GKman
02-24-2008, 07:32 AM
G'day

A quick and dirty method might be to make up a front piece to bolt and stud on to the front of the tailstock. It only need be 1/2" to 12mm thick bored for an exact fit around your quill. You could argue that you would loose that amount of quill travel but my guess is that you seldom start with the quill wound right back. This method needs no boring and only requires drilling and tapping three holes in the front face of the tailstock. It may pay to face the front to make it true, this could easily be done with a tool in the 4 jaw chuck.

To ensure centering of the new nose I would drill radial holes into the retaining screw holes in the nose, tap these radial holes and put set/grub screws in them the bear on thin sleeves on the retaining screws. The retaing screws would be just nipped firm and the final centering made by adjusting the radial set screws before nipping the retainers right up.

One good turn deserves another

Regards
Ian

A half pound of iron and a few screws from the scrap box? One easy bored hole? No lasers, edm, sightings of the north star? Sorry, move along stranger, we don't need any more of your World's Fastest Indian Motorcycles here.:p

Welcome Ian and always remember to keep your hands inside the car at all times -THE ANIMALS BITE!

Paul Alciatore
02-24-2008, 12:27 PM
I don't know which method to suggest but I am paying attention to see what happens. I also have the same problem on my SB, but perhaps not as much.

One thought: all the methods seem to require some boring. You said your boring head is somewhat small. I have seen pictures of a boring bar held off center in a four jaw. I haven't done this myself, but it may help.

Please let us know what you do, if possible, with pictures.

wierdscience
02-24-2008, 01:33 PM
Get a 9x20 tailstock barrel from Grizz for $14.26,it's 26mm OD and ground all over,bore your tailstock to fit and bore the barrel to fit your screw's bronze nut:p:D

J Tiers
02-24-2008, 07:33 PM
Get a 9x20 tailstock barrel from Grizz for $14.26,it's 26mm OD and ground all over,bore your tailstock to fit and bore the barrel to fit your screw's bronze nut:p

Good idea, but no cigar.......

That'd be so loose I'd never get it to lock........26mm is a half mm over 1", but the ram now is 1.125, or about 28.6mm.

besides, I wonder about the taper in those..... probably a metric version of a morse........ ;)

darryl
02-24-2008, 10:45 PM
I don't know- would a guy look a little funny going into a tool store with an old piece of morse taper tooling and a felt pen? I just thought of this as I read the last post- seems like a good idea if you need to get home with an adapter or whatever, knowing that the taper is correct.

It would be a bit more difficult to take your spindle in to check that the new backplate goes on properly-

wierdscience
02-25-2008, 12:07 AM
I wonder if you could have the bore plasma coated with CI power and then bore it?

rdfeil
02-25-2008, 01:41 AM
Heres an idea. I don't know how good it is but I will throw it out for thought.
Drill and tap 4 or better 6 holes around the bore from the sides, probably 3/16 to 1/4. Then I would insert small brass pins with one end cupped to match the diameter of the quill then run steel setscrews in to push the brass pins into the quill. you could indicate the quill and adjust for center. Then lock the setscrews with a follower setscrew. The brass should allow a good enough bearing surface to allow the quill to slide and it is easily adjusted for wear and replacement of the brass pins.
Just a thought.

Robin

jimsehr
02-26-2008, 12:37 AM
Have you seen this ebay tailstock? 110226783667
Jim

lazlo
02-26-2008, 10:36 AM
Jerry, whatever you end up doing, please post a follow up. I'd love to see your final solution...

Jim2
02-26-2008, 10:54 AM
I'm following this thread with interest, too. I've got a 1924 Leblond 15" Heavy Duty, and the tailstock is worn. I'm not sure if it's the ram or the tailstock bore, but I suspect it's the bore. I can still tighten the lock enough to keep the ram from moving, but it takes "significant effort"!

I'm inclined to use it the way it is for as long as I can. I don't want to muck it up any worse than it is. I'm a relative noob. I've had the lathe since 2005, and I don't get to work on it as often as I'd like.

Does anybody have any pictures of tailstock fixes?

Jim

kendall
02-26-2008, 01:20 PM
No pics, but most of the reapairs I've seen were done either by sleeving the ram, and boring the tailstock to fit the new OD, or turning the ram, then sleeving and boring the tailstock casting to fit.

Either way takes care of the wear on both components, and can be done 'at home' with minimal fuss

Ken.

Oldbrock
02-27-2008, 07:45 PM
I forgot to mention, if you have not fixed your tailstock yet, make sure your tailstock is perfectly aligned with your headstock if you are going to bore out the end. suggest you use a coax indicator and dial about 2" back, away from the bell mouth. Peter

J Tiers
02-27-2008, 10:00 PM
No pics, but most of the reapairs I've seen were done either by sleeving the ram, and boring the tailstock to fit the new OD, or turning the ram, then sleeving and boring the tailstock casting to fit.

Either way takes care of the wear on both components, and can be done 'at home' with minimal fuss

Ken.

And there really isn't enough "meat" for either option, nor will the ram lock work with much of an over-bore for a fatter ram. At least not for a complete full-length overbore for a sleeve, or for a sleeved ram of a size that is fairly reasonable to make.

I suggested, almost as a joke, Logan selling "0.020 over" rams for just this situation, much as the small engine folks used to sell oversized pistons. I think the idea fell flat with Scott, but there were some others who chimed in and liked the idea.

TGTool
02-27-2008, 11:19 PM
I forgot to mention, if you have not fixed your tailstock yet, make sure your tailstock is perfectly aligned with your headstock if you are going to bore out the end. suggest you use a coax indicator and dial about 2" back, away from the bell mouth. Peter

Alternatively lock the quill and just dial it. The wear is on the back side, and locking it will crowd it to the front. The vertical is automatic since that's the spindle height.

Oldbrock
02-27-2008, 11:41 PM
Alternatively lock the quill and just dial it. The wear is on the back side, and locking it will crowd it to the front. The vertical is automatic since that's the spindle height. With the new co ax indicator I just bought I found that the tailstock had dropped .002", had to shim it up between base and body.

daryl bane
02-27-2008, 11:42 PM
I'll add this to the mix. We had professionally ground out the tailstock bore straight and true. Unfortunately it was still out about .005. We decided to lap the bore. After alot of work, we got it within .0001. We then had the tailstock quill hard chrome plated up to size and then ground to fit. We were shooting for a final fit of about .0002. After three tries with a reputable plater/grinder, that could not hit the required tolerance, I have decided to make my own quill and grind it myself, dammmit!:)