My Tailstock is worn out!!!

[Brian Rupnow]

Well, not my tailstock, but that on my Chinese 10" x 18" B2227L lathe from BusyBee tools. The lathe is probably about 5 years old now, and has been used only as a hobby lathe (but used a lot). I notice now that when I go to drill a hole in something held in the chuck, that if the drill doesn't get started exactly on center, that the whole tailstock drill-chuck will visibly "orbit" as the part in the main chuck revolves. The quill that slides in and out doesn't appear to have any visible wear. I have measured both ends of it and there is no appreciable taper.--However, I can hold the chuck in my hand and by putting pressure on it towards myself and then away from myself, I can feel the quill move side to side---and its the quill that is moving, not the MT2 taper on the back end of the drill chuck. This is not a good thing. It appears that the hole in the casting that the quill slides in must be worn. I'm not sure that there is any "fix" for that. I know it didn't do that when it was new. I guess I'll have to phone BusyBee tools tomorrow and ask about the price and availability of a new tailstock.---Brian

 

[Sshire]

Brian
How about boring the tailstock and inserting a sleeve?

 

[Brian Rupnow]

Sshire--I don't really think I have machinery capable of doing that. I have posted a picture to show the state of affairs. With the quill extended 1.25" and not locked, there is .002" slop to each side, giving a total of .004". Of course, when you get out to the end of a drill held in the chuck, that number becomes considerably greater. I don't know if this is significant wear or not, as I have never had a lathe before this one.---Brian

 

[Art K]

Brian,
Does it help any if you snug down the quill lock? Could help temporarily.
Art

 

[Wizard69]

Sshire--I don't really think I have machinery capable of doing that. I have posted a picture to show the state of affairs. With the quill extended 1.25" and not locked, there is .002" slop to each side, giving a total of .004".

I'm not sure I like how you are stating that, but it doesn't matter that could be a lot of slop. I say could be because ideally you would mount the indicator base to the tailstock itself to eliminate potential errors from slop else where.

Of course, when you get out to the end of a drill held in the chuck, that number becomes considerably greater.

Obviously you will see more deflection further out from the casting. The thing is you also have other pieces contributing to that deflection.

I don't know if this is significant wear or not, as I have never had a lathe before this one.---Brian

As an alternative to boring and sleeping you might want to consider hard chroming the quill. That would build up the quill enough to get a like new fit. You would likely need a slightly oversized reamer and then some hours of hand fitting. In fact I see this as a better approach than sleeving.

 

[Brian Rupnow]

I have checked the quill lock, and all it is is an M6 threaded shank that screws down until it bottoms out in a slot in the top of the quill. It does take out the "slop" when tightened, but even at only partially tightened it makes it impossible to advance or retract the quill. I have called BusyBee this morning, but I don't hold out a lot of hope for buying "fix it" parts.

 

[MCRIPPPer]

the drill bit wandering is not really caused by a loose tailstock. the flexibility in drill bits cause them to wander all over the place until there is a hole starting. the slop just makes it a little worse. do you center drill before drilling?

 

[Brian Rupnow]

Yes, I always center drill before drilling, otherwise, as you say, the drill will wander all over the place before it "bites".---And if it "bites" off center, the resulting hole will be "off center".

 

[Brian Rupnow]

Today I pulled the quill out and it mikes at 1.180" which is 29.97mm. I did my best to get a reading on the tailstock housing with my telescoping bore gauges, and it appears to measure 1.181" or 29.997mm. I called Busy Bee, and the new quill is $45.14 including tax. A new tailstock housing is $179.70 including tax. If I can work on the assumption that the bore when new was 30mm, then all of the wear is on the quill. The quill is soft mild steel--I was able to machine it a few years ago when I installed a scale on the visible portion that extends past the tailstock housing. The housing appears to be cast iron. I guess my best bet at this point is to buy a new quill and hope that 99% of the wear was in the old quill, not the old housing. What is the most likely to have worn?--The mild steel quill or the cast iron housing? My gut tells me that the mild steel quill is probably the most worn. because the cast iron does have some built in lubrication because of the high graphite content in cast iron, but that's only a guess. Opinions please---

 

[canadianhorsepower]

Today I pulled the quill out and it mikes at 1.180" which is 29.97mm. I did my best to get a reading on the tailstock housing with my telescoping bore gauges, and it appears to measure 1.181" or 29.997mm. [/QUOTE

]

Brian-- If that all the play you have .001 total I wouldn't bother
when drilling hole you need more then this as a clearance and most drill
have more then .001 size difference then what's mark on the sticker
even the standard chuck you have on the picture have more then this.

 

[Brian Rupnow]

Yes Luc, I agree. I have a fairly good relationship with the local BusyBee store. I may borrow a quill out of a new machine and try it in my 5 year old lathe and see if I can detect any difference. I may be seeing a problem where there isn't one.---Brian

 

[Philjoe5]

Brian,
I'd make a dowel 1.182" and see if it fits in the tailstock (without removing it from the chuck). If not, reduce it in diameter to 1.181" (or a bit higher). Repeat until you get a good close fit. Then, push it into the tailstock, lock it and check it for wobble. If none then you know what diameter the quill should be. Maybe Busy Bee or someone on this board can mike theirs and tell you what it should be when no wobble is present. I have a Grizzly 10x22 but my quill is 1.259".

Phil

 

[Brian Rupnow]

I took my old tailstock quill over to BusyBee this afternoon. They let me remove a brand new quill from the display machine on their floor to measure, and there was only 0.001" difference between it and my old quill. I then tried to get a measurement inside the new tailstock housing, but it was packed so full of that cosmoline/shipping grease crap that I couldn't get an accurate measurement. I'm back to square #1 now, so perhaps I'll just leave things alone for now. If it causes a problem in the future, I will deal with it then.---Brian

 

[Lakc]

I would be tempted to grab some copper sulphate drain cleaner and copper plate the quill.

 

[goldstar31]

The test would have been to swop tailstocks!
Somehow, I think that this 'wear'- real or imagined is not what is causing the off centre drilling.

There is a classic way of checking and that is to put a test bar between centres- and then clock it. Has this been done?

I sometimes muse about the errors which occur from simple things like centres ( which are not true) and drill chucks( which are hopelessley out) and drills which are in these drill chucks and are worn or have unequal lips.

I might be wrong but I'm following the classic way of determining 'Truth'

 

[pete]

Brian.
At the risk of being judged a total A-hole? Items like this do need to be discussed at the 1955 "Machine Tool Reconditioning" book by E.F. Connelly level. The Schlesinger book for the limits of accuracy would be another good one I can think of. And I could really care less about hobby or professional levels of accuracy, the above still needs to be read and more importantly understood, and it really isn't optional reading. But without reading either it's extremely doubtful you'll ever understand or maybe even agree with very much of what I'm trying to explain.

I highly doubt your tail stock was ever correctly machined to begin with Brian. If it was? I'd expect it was pure fluke and far past blind luck. And I'd bet some pretty large coin you won't ever get a replacement tail stock that does anything close to what your expecting. 1,000 - 1 odds in fact.

Your tail stock needs to be very closely aligned in all three dimensions to both the headstock and the lathe's ways. Extremely accurate and dependable .0001 reading DTI's need to be also used, and the very real and expected gravity effects that ruin even a good DTI's readings need to be very well understood and compensated for. You also might research the industry standard 10 x rule for accurate and dependable measurements.

Why would you buy a new tail stock casting? Your original was a hell long ways from being correct in it's brand new condition if you consider you most likely didn't measure it accurately anyways, or if you even measured it. Your first requirement is to get the tail stocks sliding & bearing ways flat, correct, and then aligned to the headstock/lathe ways. A between centers boring bar with a temporary tail stock, and your tail stock set up on the cross slide, then those corrected tail stocks bearing ways properly aligned will give you a precision bored tail stock that can use precision bored and honed pressed in bronze wear bushings. You then end up with a far more precise and longer wearing system you've built in your very own shop.

There's obviously an excellent reason a fully rebuilt Hardinge HLV costs $60,000 or more for that rebuild, and gawd knows how much for a fully rebuilt Moore jig borer. If you can't rebuild to a far better accuracy level than what the standard unhardened/unground accuracy levels are for the average Chinese level of equipment? Then you sure need to upgrade your understanding and education.

It would cost you $90.00 - $100.00 for the Connelly book, and $20.00 - $40.00 for the GHT book that gives you the between centers boring bar design. But you should gain almost an unlimited amount of knowledge about machining that I think your missing.

Pete

 

[Lakc]

Items like this do need to be discussed at the 1955 book "Machine Tool Reconditioning" book by E.F. Connelly level.

Thats been on my read list for as long as I can remember, however, it goes for a very premium price whenever I see one.

 

[pete]

Sadly Jeff you are 100% correct. But I sure do wish you wern't. For at least the English language, there isn't and hasn't been anything written since 1955 that can replace that Connelly book. There is talk of a replacement by people like Richard King, but so far there`s nothing I know of. But to be 100% honest? That $100 would be the cheapest money you'll ever spend in your shop even if your paying the brand new price.

LOL, I can say if everyone was required to read and mostly understand the points of view in that book you`d see a hell of a lot less misinformation posted on any of these forums.

Pete

 

[goldstar31]

As Pete says- there are books and there is 'information'
There is a wealth of wisdom which is not being taken up by newcomers.
Would you believe that I have an old associate of mine who is not quite the guy with 'toy' engines but whole fullsize locomotives and is a world authority on them- and full size tug boats with real dirty smoke coming out of them and his enclosure with two of his books says:-
'In spite of making this definitive information( it was on Stephensons Gear and Walshaerts Gear), I still see questions in ( he said magazines being no internet really then) asking the same old things- and getting the same silly answers'

I was amongst a gang of professors and managers of power stations and all sorts of workshops last week- and they were all still referring to 'Don' not just in engineering but music!

It was a heady mob- believe me.

So back to Connelly and a few more lessons. There is a lot of idle prattle about these people who have these clock gauges and 'vernier things' which measure- with a fair wind and tide, two thous and they need tenths of thous to establish 'truth' Again, they expect miracles from instruments that measure things but can't check the tools that should make them.

Perhaps, I've said enough. If your feathers are being ruffled- tough luck!

Norman

 

[Brian Rupnow]

My feathers weren't ruffled. I am fully aware that there are books available from "experts" available on every subjects from sex to skydiving. I am capable of seeing what appears to be a problem. I'm not always sure just what to do about the problem, but a good start is to discuss it with other people who use the same equipment and see if they consider it a problem or not. Thank you all for your helpful contributions.---Brian