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Wandering mill table

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Martin Connelly23/10/2021 15:25:30
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1929 forum posts
207 photos

Not flexing the table but probably some induced rotation about a vertical axis, this is unavoidable unless you tighten the gibs to the point where the bed can't be moved. An advantage of a powered drive is that there is just torque applied to the leadscrew, no pushing and pulling at 90° to the leadscrew axis. It would be a good exercise to see if you can drive the bed with a variable speed drill to reduce the pushing and pulling that comes from hand cranking. That will give a truer indication of the set-up you are achieving. With a spoked wheel a simple fork shape in a chuck can be enough but it looks like you have solid wheels in the photos above.

Martin C

Dave Halford23/10/2021 15:30:58
1816 forum posts
19 photos

Maybe a bent leadscrew?

Steve35523/10/2021 16:05:20
128 forum posts
87 photos
Posted by Martin Connelly on 23/10/2021 15:25:30:

Not flexing the table but probably some induced rotation about a vertical axis, this is unavoidable unless you tighten the gibs to the point where the bed can't be moved. An advantage of a powered drive is that there is just torque applied to the leadscrew, no pushing and pulling at 90° to the leadscrew axis. It would be a good exercise to see if you can drive the bed with a variable speed drill to reduce the pushing and pulling that comes from hand cranking. That will give a truer indication of the set-up you are achieving. With a spoked wheel a simple fork shape in a chuck can be enough but it looks like you have solid wheels in the photos above.

Martin C

Actually the table wheels are spoked. I might give that a go.

I did have the best genius idea of putting some oil on it earlier and it seems to turn a lot more easily.

I am beginning to want to add a power feed already.

Pete Rimmer24/10/2021 22:29:41
1094 forum posts
69 photos

If the table is rotating simply from turning the handle either the ways are worn or the leadscrew is bent. It's also possible that the leadscrew nut is machined slightly too tall and the bed is riding on the leadscrew somewhat. Check for a bent leadscrew by turning it slowly by gripping the wheel not the handle. If it's bent it will move your dial regardless of how it's turned.

Steve35524/10/2021 23:08:18
128 forum posts
87 photos
Posted by Pete Rimmer on 24/10/2021 22:29:41:

If the table is rotating simply from turning the handle either the ways are worn or the leadscrew is bent. It's also possible that the leadscrew nut is machined slightly too tall and the bed is riding on the leadscrew somewhat. Check for a bent leadscrew by turning it slowly by gripping the wheel not the handle. If it's bent it will move your dial regardless of how it's turned.

Thanks Pete

I’ve examined the lead screw and it isn’t obviously bent, but I will take another look.

there is a stiffness in the handle that always occurs in the same place in the turn. I think that whoever is causing it, is related to that,

cheers

Steve

Howard Lewis25/10/2021 15:42:21
5528 forum posts
13 photos

If you grip the ends of the table, and can wobble it back and forth, the gibs are not set correctly.

I would expect the gibs to be trapezoidal in section, Wide faces at an angle to matc h the dovetails, but with the narrow faces horizontal, and not fouling on any other part, with the adjusting screws engaging in the dimples.

Ideally, the gibs should be adjusted with the leadscrew disengaged. (Removed? )

If the table gibs can be adjusted so that it moves smoothly, but with absolutely minmial slack, but it tightens when the leadscrew is fitted you need to investigate the leadscrew and the nut, Possibly as suggested the nut is out of place in some plane.

HTH

Howard

Tony Pratt 125/10/2021 15:48:38
1752 forum posts
8 photos

Howard, the Dore Westbury mills do not use dovetail slides, they are just plain bars.

Tony

Steve35525/10/2021 16:02:19
128 forum posts
87 photos
Posted by Tony Pratt 1 on 25/10/2021 15:48:38:

Howard, the Dore Westbury mills do not use dovetail slides, they are just plain bars.

Tony

That’s right, and also they have an aluminium tray at the end which is nothing like as solid as the cast iron. This provides a very long lever arm to wobble the table laterally.

Pete Rimmer25/10/2021 18:35:55
1094 forum posts
69 photos
Posted by Steve355 on 24/10/2021 23:08:18:

Thanks Pete

I’ve examined the lead screw and it isn’t obviously bent, but I will take another look.

there is a stiffness in the handle that always occurs in the same place in the turn. I think that whoever is causing it, is related to that,

cheers

Steve

That can only be a bent or poorly manufactured screw.

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