OK now I'm kind of confused. I assumed from your first post & pic showing DTI on outside surface of spindle nose, that it indicates 0.004" runout relative to bearing/shaft. I assumed it was a type-L (not that it really matters) & so the inside taper was going along for the ride & have similar runout. Are you saying the DTI reading between outside & inside surface is different to each other on the same test setup & that will adversely affect turning between centers with a center arbor in place?
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Spindle nose re-grind?
- Thread starter phaxtris
- Start date
OK now I'm kind of confused. I assumed from your first post & pic showing DTI on outside surface of spindle nose, that it indicates 0.004" runout relative to bearing/shaft. I assumed it was a type-L (not that it really matters) & so the inside taper was going along for the ride & have similar runout. Are you saying the DTI reading between outside & inside surface is different to each other on the same test setup & that will adversely affect turning between centers with a center arbor in place?
You are correct, the inside taper is going along for the ride, same runout as far as I can tell as the outside taper
One can just true up the faceplate, and then a soft center would need to be made and trued up each time (although like mentioned a whiteness mark on the center and the spindle nose would make it much less)
Trueing up the faceplate & turning a new center in-situ kind of works for centered turning (only). But assuming I understand the L spindle correctly, isn't the bigger issue that the other 99% of the time, whenever you mount a chuck or anything referencing off the spindle OD, it's going to have corresponding (actually exaggerated) runout for stock holding?
Tom Kitta
Ultra Member
At least you have standard MT. My British machine is MT4.5 Yep, 4 and a half. There is a big jump from 4 to 5 and smaller machines would have hard time getting to MT5. But MT4 is small and too small for collet systems... so MT4.5 was born. Good luck finding it for sale - you got to roll your own... BUT even that is not easy as pp do not agree as to what dimensions 4.5 has - many say its same as MT4 taper just bigger....
I actually never missed not having MT4.5. To really "feel it" I would need a special case where part is so long that I cannot just put in a center inside of 4 jaw chuck! With 4 Jaw (or collet chuck) I can re-use the center not cut it every time. Also my ER40 collet chuck looses maybe 3".
So realistically its not an issue 99.9% of the time. And for rare times it would be an issue I have a bigger lathe...
All the chucks for L ( that I have at least) are mounted to a backing plate that is turned in situ, and indexed with a keyway on the spindle nose, so the only runout induced from the spindle taper is whattever slight slop is in the keyway allowing the backing plate to mount not in the *exact* same location every time. I'm sure there is at least .001 or more of clearance there, Wich by the time you figure the rotation on the nose that allows, probabaly give some amount of runout (to a 3j Wich runs out anyways, or a 4j Wich you have to dial in)
So what your saying is, come to your house when I need something to long for a center in the chuck right
OK, so let's just drop this part of the conversation. I was only trying to point out that you need to drive the dog with something. I thought somebody said you just needed the centre to get the most length. But a faceplate loses some of that. So I was asking how you would drive the part without the faceplate.
But all that just got everyone confused. You are not planning to use the centre anyway.
It's all good. Just forget about the spindle center. Make one for your 3-jaw chuck and start makin stuff!
Yea there is a lot of going back and forth, and confusion, but I don't lose any length with the faceplate, do you lose length on a camlock with a faceplate ? I'm guessing that's what you have ?
Yes, I do. And yes I do! LOL!
But it is a zero problem for me. I have a 40" bed.
Let me put that a bit differently. One of my chucks (one I made myself) has an integrated set of three spiders. It is over a foot long!
I don't have a machine length problem at all for anything I do.
I had a SM once that had the 4.5. Ideal for collets as you say. It was big enough to fit the most common collet size, 5Cs. With the factory adapter (very well made and hardened) it was like a really big watchmakers lathe. So nice, I miss that lathe. I've now got a Swiss Habbeger with a (somewhat rare?) 5C spindle nose, not parting with that one!
I have seen dimensions for 4.5 published in MT tables, but no idea if most/all/few manufactures followed it.
While not nearly as nice as having an integral 5C spindle nose like yours, I have a bison 5C Collet chuck for my D1-5 Camlock Spindle. I LOVE IT. It is the chuck that lives on my lathe the vast majority of time.
It's easy to see why you love yours.
kind of works? imo its the preferred approach to setting up to turn between centres. It eliminates the sources of error at the headstock centre and creates a centre perfectly aligned to the lathes bearings, i.e. zero runout. (concentric taper bore, dings or bumps or debris in headstock/adapter mount, eccentricity in the taper adapter, eccentricity in the centre, dings or bumps or debris in between centre/adapter).
Not sure how the faceplate entered into? How do you hold the centre you turning in situ, and what does the faceplate to? Below is a typical setup I'd use - this roughing out a new spindle shaft for a small mill on my DSG. Quick, easy and imo the most accurate set up.
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Direct mounting dude....next level
. I bought that lathe last year for well under 2k with a full (by 64ths) set of 5C hardinge collets....and not like it was a secret or a hot deal. I do know the seller, but it sat on kjiji for weeks and nobody called him. I've got a Schaublin 102 i'm going to sell, W20, so smaller, but it is the same idea. direct mount and has a few schaublin collets. Busy Bee on speed dial and the Swiss lathes don't sell lol. Probably thats not 100% fair as they are not threading, but it does amaze me that it sat on kijiji and wasn't snapped up instantly.I'd posted a bunch of the Habegger photos here, toward the end....There is also a video of showing not a tenth runout with a collet....Busy Bee's on speed dial and the Swiss lathes don't sell lol.
Schucks, now the shop is even more crowded shop - collets and a Habegger
you are welcome and apolgies for the the verbosity...been thinking about it so long it refreshing to share it with someone who might benefit from some of it
canadianhobbymetalworkers.com
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@Mcgyver I'm not disputing that turning a sacrificial center in-situ will make it run true relative to the rotation axis. I'm reconfirming what I think OP is collectively saying:
- the spindle nose OD has 0.004" runout as measured by DTI while rotating in the lathe environment (that's a problem)
- the spindle socket ID has similar runout when measured at the same time (so I'm inferring the spindle nose as a unit is somehow off axis, relative to the bearing axis)
- the spindle nose runout measures similarly with spindle removed from lathe & supported on roller test apparatus (not quite sure this distinguished where the source of distortion is occurring but interesting nonetheless)
So then the conversation went to how to accurately support stock between centers. And I'm agreeing with you, about the only viable option is to insert a sacrificial center & turn it in-situ. The mention of face plate comes from OP, not me, post #1
So the question is...has anyone ground a spindle nose and Morse taper with a tool rest grinder in situ? Or should I just live with it... skim the face plate and turn a center in pos when I want to run faceplate/center?
And, presuming the face plate mounts to the spindle nose OD like a chuck, skimming it doesn't do a lot of good because presumably its only purpose is to offer a slot for the lathe dog?
And what I'm now asking is: ok now you have a method to turn between centers. As most people expressed, that turning mode probably only represents a small percentage of lathe work holding where say a chuck would be mounted on the spindle nose & thus go along for the ride with spindle nose run-out.
If I'm still missing the picture, I'll come back in a few days & maybe the fog will have lifted. (It may well be confined to my brain LOL).
Dabbler
ersatz engineer
@phaxtris Here's a solution for what it is worth. make a MT bar out of soft material that will fit your wonky spindle -- wait for it -- and then 'turn in place' your 60 degree centre, just as *if* it was held in a 3 jaw chuck. You will gain the precious 4 inches or so. the cost is that every time you remove it, you will have to recut it. Run your dog in the faceplate as usual.
I reread the thread several times, but I didn't get that this was the agreed solution. If it is, chalk it up to my advancing years.
I reread the thread several times, but I didn't get that this was the agreed solution. If it is, chalk it up to my advancing years.
@phaxtris Here's a solution for what it is worth. make a MT bar out of soft material that will fit your wonky spindle -- wait for it -- and then 'turn in place' your 60 degree centre, just as *if* it was held in a 3 jaw chuck. You will gain the precious 4 inches or so. the cost is that every time you remove it, you will have to recut it. Run your dog in the faceplate as usual.
I reread the thread several times, but I didn't get that this was the agreed solution. If it is, chalk it up to my advancing years.
I believe your solution is indeed new. And its a good one too. Your advanced years brain is still working great!
That said, @phaxtris has indicated that he has no immediate need for the extra 4 inches. (Lucky guy) It was more of a "what if I ever did need" question. As such, using the chuck is just plain easier to make the sacrificial center because there is no need to make the MT taper to go with it.
Here is how Standard Modern made sure there is maximum distance between centers available on their lathes:
They use a special “dog plate” to drive the dog. Looks like a face plate, but it is not. The center is held in a precision ground (and hardened) spindle bore adapter.
This is where the OPs problem would lie since there is a good amount of runout inside his spindle bore.
The solution as suggested by @Dabbler using a “soft“, machinable center (which needs turning before each use) will give max distance between centres. If max distance is not crucial, just do as others have suggested and true up a piece of steel held in either the 3J or 4J and use a chuck jaw as a drive point.
They use a special “dog plate” to drive the dog. Looks like a face plate, but it is not. The center is held in a precision ground (and hardened) spindle bore adapter.
This is where the OPs problem would lie since there is a good amount of runout inside his spindle bore.
The solution as suggested by @Dabbler using a “soft“, machinable center (which needs turning before each use) will give max distance between centres. If max distance is not crucial, just do as others have suggested and true up a piece of steel held in either the 3J or 4J and use a chuck jaw as a drive point.
So I have no opinion on how anyone else should do this. Perhaps it's my Gingery Lathe building background but I like turning stuff between centers. And way way back when I bought my lathe one of the people on the South Bend group was making the special SB Taper to MT3 taper adapters. So I bought one. My only complaint is that the MT3 center doesn't recess deep enough.
And it takes very little time to spin off the the current chuck or remove the 5C collet holder and insert the Center and spin on the drive plate.
After that it's just a matter of turning whatever needs to be done between centers. In this case to do the pulleys the arbor was swapped end for end a few times.
When done, tap out the insert and un-thread the drive plate and replace with whatever.
I really like this approach. And one day I'll turn a new MT3 center that is recessed closer to the drive plate. One day...
And it takes very little time to spin off the the current chuck or remove the 5C collet holder and insert the Center and spin on the drive plate.
After that it's just a matter of turning whatever needs to be done between centers. In this case to do the pulleys the arbor was swapped end for end a few times.
When done, tap out the insert and un-thread the drive plate and replace with whatever.
I really like this approach. And one day I'll turn a new MT3 center that is recessed closer to the drive plate. One day...