Tailstocks

[artme]

One thing that really came home to me when I was trying to sort out the lathe I had borrowed here was the issue of the tailstock, not only on this, but on other lathes.

Amos made a comment about tailstocks on metal lathes and that made me think about deficiencies in design in this area.

I believe that a longer base on the tailstock and more precisely machined surfaces on both the lathe bed particularly the insides of the rails, and a more precisely matched mating area on the tailstock would solve a couple of problems.

# Sideways slop would be eliminated or, at least minimized.

# drilling on the lathe could be more precise.


What do others think.??

[bobsreturn2003]

hasnt been a problem with my woodfast or jet , you can check head and tail stock line up with a couple of dead centres . otherwise most wood lathes there is little adjustment , if you have a real problem suggest you post some pics,

[Phil Spencer]

Don't have a problem with my Tough either :)

[Big Shed]

Arthur I have posted a reply to Amos in my mini lathe thread

http://www.woodworkforums.com/f69/bought-new-mini-lathe-110151/#post1081989

[Big Shed]

Don't have a problem with my Tough either :)

Phil, as I said elsewhere, the Tough lathe looks like a nice bit of kit. However when all is aid and done it is at least 20-30 years old and a very basic wood lathe. According to Len Smith he wants about $1500-1600 for them.

[hughie]

# Sideways slop would be eliminated or, at least minimized.

# drilling on the lathe could be more precise.

What do others think.?


Yes I agree this becomes an issue when you own something like a MC1100. Both head and tail stocks had this problem. I spent quite a few hours rectifying the headstock, got it to a point where it was reasonable.The tailstock I left as it was major hassle and doing bowls I more or less got away with it.

[Phil Spencer]

Phil, as I said elsewhere, the Tough lathe looks like a nice bit of kit. However when all is aid and done it is at least 20-30 years old and a very basic wood lathe. According to Len Smith he wants about $1500-1600 for them.

Seems that some times old technology is better that new fangled technology

[tea lady]

Phil, as I said elsewhere, the Tough lathe looks like a nice bit of kit. However when all is aid and done it is at least 20-30 years old and a very basic wood lathe. According to Len Smith he wants about $1500-1600 for them.:hmm: There ain't much more to a lathe is there?

I think what some need is a way to adjust the tail stock. :shrug: Some sort of screwy slidey mechanism. :think: But then your little cheap lathe wouldn't be little and cheap anymore. :doh:

[hughie]

I think what some need is a way to adjust the tail stock. :shrug: Some sort of screwy slidey mechanism. :think: But then your little cheap lathe wouldn't be little and cheap anymore. :doh:
[/QUOTE]

You got it in one. Metal lathes have this ability. But very few Wood lathes I have seen have it and this includes the fancy ones.

[issatree]

Hi All,
Hey, we are talking Wood Lathes here, not precision made Metal Lathes.
My "Tough" has been out by approx.1mm the last 19 years, & it hasn't made any difference to my work.
I thought it was to big a job to tackle, so I just left it.
Regards,
issatree.
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[funkychicken]

Metal lathes have V beds which works fine if you're only moving things along the V. A tool rest on a woodlathe needs to move in all directions so V beds wouldn't work.

I've long thought that four bearings on the bottom of tailstocks to act as buffers would be good

[rsser]

Hi All,
Hey, we are talking Wood Lathes here, not precision made Metal Lathes.
My "Tough" has been out by approx.1mm the last 19 years, & it hasn't made any difference to my work.
I thought it was to big a job to tackle, so I just left it.
Regards,
issatree.
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Depends on the kind of work you do.

[Big Shed]

Hi All,
Hey, we are talking Wood Lathes here, not precision made Metal Lathes.
My "Tough" has been out by approx.1mm the last 19 years, & it hasn't made any difference to my work.
I thought it was to big a job to tackle, so I just left it.
Regards,
issatree.
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If my pen lathe was out by 1mm, my pens wouldn't look too round:o


Depends on the kind of work you do.

Yes, you got it in one Ern, if I was doing bowls or relatively big spindle work it wouldn't worry me too much. But on a 12mm pen, 1 mm is a lot of deviation.

Even the 0.6mm the mini lathe is off centre on the headstock spindle is very significant, take out a set of feelr gauges and pick out the 25thou/0.6mm one and see how thick that is, then imagine your pen being out of round by that much:no:

[Big Shed]

Metal lathes have V beds which works fine if you're only moving things along the V. A tool rest on a woodlathe needs to move in all directions so V beds wouldn't work.

I've long thought that four bearings on the bottom of tailstocks to act as buffers would be good

Not very difficult to do FC, look at the cross slide and the compound slide and saddle, very easy 3 way adjustments. Take away the precision dials and make it easier to adjust and you have more precision.

[stuffy]

If my pen lathe was out by 1mm, my pens wouldn't look too round:o



Yes, you got it in one Ern, if I was doing bowls or relatively big spindle work it wouldn't worry me too much. But on a 12mm pen, 1 mm is a lot of deviation.

Even the 0.6mm the mini lathe is off centre on the headstock spindle is very significant, take out a set of feelr gauges and pick out the 25thou/0.6mm one and see how thick that is, then imagine your pen being out of round by that much:no:

If you know it's out by that much why not put a shim that size under the tailstock on the appropriate side. :? Or machine a little off the other side???
Just my 2c's,
Steve :)

[Big Shed]

If you know it's out by that much why not put a shim that size under the tailstock on the appropriate side. :? Or machine a little off the other side???
Just my 2c's,
Steve :)

Steve, the problem on my new mini lathe can't be fixed by shims, the female MT2 taper has not been machined in the middle of the headstock spindle, but is 25thou/.6mm off centre to the OD.

See here

http://www.woodworkforums.com/f69/bought-new-mini-lathe-110151/

[artme]

We all seem to have missed the point I made about drilling on the lathe.

If you drill a blank for a kit that finishes with a very thin layer of material on the tube then it can be a problem withe the drill bit wandering and the risk of some part of the hole being oversized.

[rsser]

Sometimes, if you're only going off a pen round and you get ecc'y, check the mandrel shaft for true.

[issatree]

Hi Fred & All,
I have made 100's of pens on my Tough, Fred, never had a problem, but as I understand it, I think you mainly turn yours on a Metal Lathe, BIG difference.
Maybe these new pen types out now, might make it different, as I haven't turned one for ages.
Regards,
issatree.
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[artme]

Sometimes, if you're only going off a pen round and you get ecc'y, check the mandrel shaft for true.

Fair enough Ern. I guess that should go without saying but is something easily overlooked. However that still doesn't address the concern of the tailstock slop.

I have a Nova TL 1200, same as Corbs. Tailstock is a bit of a pig as it doesn't have a cam-lock - nor does the toolrest banjo. I'll be looking at ways to modify that when I get home.

The bed of the lathe is two pipes To fix the tailstock problem I was thinking offixing a rod or a length of angle to the outside of one of the pipes and making a matching part for the tailstock to fit over this . In theory it should be fine.

We shall see.

[Tim the Timber Turner]

Sometimes, if you're only going off a pen round and you get ecc'y, check the mandrel shaft for true.

I used to turn lots of pens but not for a while now.

I would always check the mandrel with a dial mic after fitting it to the lathe.

If it was out I would remove and refit it.

If that didn't work a tap with a hammer as a last resort.

When it became difficult to make it run true, then it was time to chuck it out and start again with a new mandrel. The problem seemed to get worse as the mandrel got older.

Tailstock slop can be adjusted with the careful use of a centre punch and a hammer. The idea being to swell the cast iron with lots of gentle hits. Go careful near the corners as you can break a piece off. Plenty of checking is required as you go. This method is used to adjust for wear on a well used lathe.

I hope this may be of help to someone.

Cheers

Tim:)

[joe greiner]

The center punch trick is sometimes used to true up carpenters' framing squares; at the inside corner to increase to 90 degrees, outside to reduce to 90 degrees. It would take a lot of punches to make much difference on a tailstock, I think.

Jointers and cross-slide vises sometimes have adjustable gibs to reduce slop, but surfaces need to be very straight. Probably adds ~$50 (?) to production cost.

Cheers,
Joe

[oldiephred]

Excuse my lack of understanding BUT-- how can the tailstock being out by 1-- 2 mm result in a pen (or anything else) being out of round or tapered? It appears to me that with the cutting tool being a free floating tool, unlike a metal lathe cutting tool, The operator determines taper and roundness and not so much re:the roundness.
What am I missing?

[artme]

Fair question.

If the two centres are not aligned then it is not just a matter o the taper being determined by a free floating tool at all.

The tool may be "free Floating" and controlled by the operator BUT how does the operator move the tool in and out on a small object spinning at any where from 2 000 - 3 000 rpms so that the tool is in synch with the "high spot".?

Not only that but you get a blank that is not only not round but a bit like a cylinder that has been sliced at a slight angle on either end.

The kit, in both cases, will not match up to the turned piece.

[joe greiner]

I agree - fair question. But I think the answer is more complicated.

Theoretically, if the work is turned between centers, its axis of rotation is determined by the two centerpoints of the spur drive and the tailstock. If the offset is horizontal only, the toolrest can be set parallel to that axis, and it "should" be possible to turn a round shape. If there's also a vertical offset, you'll have a sweet old time following it. In either case, the spur drive will beat up the headstock end, and too much compression from the tailstock can produce bowing.

Pen mandrels are usually clamped at the headstock, and any offset will produce a curved, not straight, axis of rotation. No way to cut that without wobble. A steady rest could get the tailstock out of the game, but that's beside the point. (Get it? Beside the point?). Sorry, couldn't resist the temptation.:-

Cheers,
Joe