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macca2
23rd March 2005, 11:05 AM
Hi, I have a Woodfast 280 lathe and have discovered that the headstock and tailstock do not line up accurately.
When I wind the tailstock out to the limit and then bring it up to the headstock, the centre pin on the drive is about a mm out of line with the pin in the live centre.
I can fix this by packing between the tailstock and the bed using a folded piece of 1000 grit sand paper.
Is there a more permanent fix or am I stuck with this mismatch.
Does it realy matter. :confused:

Thanks Macca

gatiep
23rd March 2005, 11:43 AM
In most turning it wont matter except if you clamp something in a chuck or screw it to a face plate and bring the tailstock up in which case the point of the live center will scribe a circle as it cannot center on the wood. Also when you try and drill a hole with a jacobs chuck held in the tailstock. For between center turning you would be hardpressed to see a difference, although if you had the turning tool run absolutely parallel to the bed like on a metal lathe the turned piece would have a slight taper. Some people have claimed out of round pens as a cause of the above problem u mentioned, but actually that is caused by either a bent mandrel or most likely too much tailstock pressure on the mandrel. It could cause a taper on the pen tho, but they are usually not turned perfect anyway.

The only fix would be a brass or other shimm fixed permanently. Unfortunately the problem is usually caused by sloppy manufacturing techniques by the people who manufactured the lathe

:)

Ross
23rd March 2005, 12:26 PM
Hi, I have a Woodfast 280 lathe and have discovered that the headstock and tailstock do not line up accurately.
When I wind the tailstock out to the limit and then bring it up to the headstock, the centre pin on the drive is about a mm out of line with the pin in the live centre.

Thanks Macca
I had the same problem on a Carbotec micro lathe, they have adjustment on the tailstock clamp (mine was out by 3mm).

Fixed now!

Ross

rodm
23rd March 2005, 11:44 PM
Macca
Unfortunately you have only proved that the misallignment is at the headstock end. The lathe bed might be the problem as well as a few other things so a more conclusive test would have to be done. On metal lathes this involves a complex series of allignment techniques and ends with a test bar turned between centres.
Don't pack the tailstock unless you are sure that the position on the lathe bed where the tailstock is parked is at a different centre height to the headstock.
Gatiep has given a very good summary of the effects of off centre and I agree with him that don't be too worried on a woodlathe.

Jeff
1st April 2005, 10:52 AM
:eek: My tailstocks are out of alignment as well, and it makes little difference overall. In a few cases such as mentioned above it can be trying but there are solutions. If I have a piece of wood I'm turning in a chuck and I want to use the tailstock for extra support, I just put a small soft obect or a wood disc between the live center and the workpiece, that way it supports the work but doesn't leave an off-center mark. The only thing it really provides a major problem with is trying to use a jacobs chuck and drill bit on a finished piece, which is pretty much out of the question. I prefer to bore with a drill press anyway. If I need to use the jacobs I figure out a way to drill the hole as a first step and then use that hole to align the workpiece for the turning work. Unless you shell out some pretty big money your lathes will most likely have a little bit of misalignment, but it's something that has been the case for centuries! Otherwise, just give yer lathe a good slap up side the headstock and get it to straighten up, mister. :rolleyes:

barnsey
1st April 2005, 02:52 PM
Most lathes these days have outboard turning facilities for the headstock. The indexes on these are +or- whatever and it doesn't take too much tolerance to get the sort of mismatch you talk about.

Now I have made the assumption that your alignment problem is horizontal and it could be vertical or both. So there is another consideration.

It could be that it's out up close but the further the distance you have the tailstock away will reduce that misalignment if the bed is a true 90 degrees to the plane/axis of the headstock.

My experience is that generally all lathes are produced within tolerances that will allow you to align head and tailstocks - you just need to play around and find where that is - ie where in the clearances everything has to be to be aligned. My last lathe was such that if I kept everything toward me when it was clamped, then it was aligned.

If you have a vertical alignment problem then shimming the head/tailstock will more likely work.

In any event the problem will only present itself when you want to perform functions at both ends and the out of alignment problem will haunt you such as when you are trying to do a precision lid on a turned body.

It's a bit like any machine - you need to make sure everything is setup correctly all the time or you will run into trouble.

FWIW Hope that helps

Jamie