Mandrel longevity

[Midnight_Turner]

So I bent the mandrel last night and I've ordered a new one from Axminster (MT 1). I seem to get around 30 pens before I have to replace a mandrel, what I want to know is a s this common? Am I going too hard? Don't think I'm going to hard as surely I'd crack the blank? Is my lathe off? It's very old and designed more for spindle work, I don't mind replacing the mandrel, but would like to know what others think...


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[Vic Perrin]

Do you use the mandrel saver Miles ? There's something drastically wrong if you are replacing the mandrel that often. I still have my original mandrel with the brass thumb screw for tightening up the blanks and it still works as new and I must have done hundreds of pens with it. I now use just the Evolution System from Axminster which makes work so much simpler and quicker

 

[yorkshireman]

Something wrong there Miles mate. I've made hundreds of pens and still on the original mandrel but then I do use a mandrel saver, it's much easier and more stable. Is the mandrel bending?

 

[Penpal]

Show us your mandrel mate, everything wrong here IMHO. There are too many unknowns, eg how the mandrel is held either end, if you use a point contact to live centre is the point 60 degree or not fitting correctly. Sounds like time to go between centres, eliminate the use of a mandrel, see how you go then.

Is the alignment between the headstock and tail stock accurate (tested with a dead centre in the headstock and tailstock meeting spot on, this tested by lightly interfacing a thinnish feeler guage between the meeting of the centres. Out of alignment can be in any direction 360 degrees.

Just a few things for starters. Show us pics of your lashe etc, think about a mandrel saver or making one.

Peter.

 

[Midnight_Turner]

Using a mandrel saver, interested in this evolution system but will post pics when I get home of the lathe etc


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[Walter]

I have had some of my mandrels for 20 years. I don't remember ever having bent a mandrel. You are doing something wrong Miles, but I really don't know what because there are too many variables that it could be.

 

[Bill Mooney]

If you use a mandrel saver you won't bend the mandrel by putting too much pressure on the tailstock quil.
Check the alignment of headstock & tailstock with the kiss test. Put a dead or drive centre in the headstock & put you live centre in the tailstock & bring them together till they just kiss. Both points should line up with each other both laterally & heightwise. If they don't then adjust your headstock. Even a fixed head lathe can be out. Loosen the bolts holding the headstockdown & re-alignthe head till the two points of your drives are in line & tighten. If the points are out heightwise then you need to pack your headstock or tailstock till they do line up. If you have a swivel head lathe then loosen your locking lever, adjust & reclamp with the locking lever. Check your swivel head regularly as it can move slightly through use. You should only need to align your fixed head once & it should be ok but it's always worth checking periodically to see if it's moved. You probably know all this but a reminder doesn't hurt. Hope it helps.

 

[Midnight_Turner]

If you use a mandrel saver you won't bend the mandrel by putting too much pressure on the tailstock quil.
Check the alignment of headstock & tailstock with the kiss test. Put a dead or drive centre in the headstock & put you live centre in the tailstock & bring them together till they just kiss. Both points should line up with each other both laterally & heightwise. If they don't then adjust your headstock. Even a fixed head lathe can be out. Loosen the bolts holding the headstockdown & re-alignthe head till the two points of your drives are in line & tighten. If the points are out heightwise then you need to pack your headstock or tailstock till they do line up. If you have a swivel head lathe then loosen your locking lever, adjust & reclamp with the locking lever. Check your swivel head regularly as it can move slightly through use. You should only need to align your fixed head once & it should be ok but it's always worth checking periodically to see if it's moved. You probably know all this but a reminder doesn't hurt. Hope it helps.

I'm still a newbie and no nothing about all this stuff, I can't even tell you what sort of lathe I have. Just on the way back from grandmas as we've been out for her birthday, as soon as I get home I'm taking pictures of the lathe and doing the dead centre test, post the results so folks can let me know what to do next


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[Midnight_Turner]

Think we are off here


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[Midnight_Turner]

As I turn it around, it goes around the tail Stock

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[Midnight_Turner]

This is my lathe

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[Midnight_Turner]

This is the model of my lathe

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[Midnight_Turner]

I wish I could upload a video of what's going on here, but to try and explain it a little better, if I turn the headstock wheel, the end of the dead centre circles the end of the dead centre in the tail Stock. How on earth do I adjust the headstock on this lathe? It's my first ever lathe and I've had it for about 8-10 months now


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[Phil Dart]

Yep, I agree with everyone else here - lots of variables to be examined before you can determine the cause. I do detect though that people seem to think that a mandrel saver is the only golden ticket to longevity.

I never use a mandrel saver, I always use a live centre in my tailstock. I replaced my mandrel in the autumn last year after 8 years of service from the previous one, on which I made 5 or 6 pens a day, 5 days a week, throughout its life. Do the maths and that is conservatively in the region of eight to ten thousand pens before I finally retired it.

So a mandrel saver isn't always necessary if you want your mandrel to last, but not applying too much pressure from your live centre is paramount.

However, you mention a dead centre, which may be a big part of the problem, and you also need to establish which of your two centres is not true, if not both.

 

[Bucks]

I never use a mandrel saver, I always use a live centre in my tailstock. I replaced my mandrel in the autumn last year after 8 years of service from the previous one, on which I made 5 or 6 pens a day, 5 days a week, throughout its life. Do the maths and that is conservatively in the region of eight to ten thousand pens before I finally retired it.

Wow that's a lot of pens Phil

 

[Midnight_Turner]

It's definitely my headstock centre not true, just don't know how to fix it


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[Phil Dart]

Wow that's a lot of pens Phil

It sounds a lot, but in reality it's just a few a day. They just mount up over the years, that's all

It's definitely my headstock centre not true, just don't know how to fix it

Does the tip of your headstock centre run true with the lathe running? I realise it points the wrong way, but is it true or is there runout?

 

[Buckeye]

Before you do anything to your headstock clean out the bore thoroughly and clean the dead centre to make sure that both are spotless and can seat properly, then do the same with the tailstock.

Peter

 

[Penpal]

Your in luck mate but first use two new dead centres for accuracy point to point. The unlucky thing is it appears as if there is no way from this view to raise or lower the head stock an open view of the bed facing the headstock to see how the rail is fitted in place. Fair number of possibles and probables to go yet. Why I say use new points both the others have seen better days.

It would appear the tail stock shaft houses a blunt point all bad imho.

Peter.

 

[Midnight_Turner]

It sounds a lot, but in reality it's just a few a day. They just mount up over the years, that's all


Does the tip of your headstock centre run true with the lathe running? I realise it points the wrong way, but is it true or is there runout?

What do you mean by a run out? The headstock circles the tailstock in not a round circle, more of an oval one...


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