New Bushes problem...

[steveasub2]

Hello All,
i wonder if anyone can help me with the following...
my lathe is in dire need of new bushes, and I am hoping that someone will have some good advice as to how I can do it.
The lathe is a "Haighton Cadet" in good nick apart from the excessive play in the split bronze bushes, even though the clamp is fully adjusted. No surprise there as they are original and close to a half-century old!
It will still take fairly clean light cuts in brass or aluminium, but struggles with almost anything else.
I can of course measure the ouside diameter of the shaft to get the required inside diameter of the bush, but how can I accurately get the dimension of the outside of the bush once it is out of the housing, as it springs open due to the split construction. Also the housing itself is hard to measure.
Does anyone else have one of these lathes, or a manual with the proper dimensions in? I know it's a long shot, but I'm desperate!
Next question of course is once I get the correct dimensions, where can I get the bushes accurately machined for me?
Anyone know of a club in the North Wales area?
That'll do for now, it's well past going home time, I'd be very grateful for any advice,
Regards,
Steve.

[David Thompson]

I imagine the slit in each bush is fully closed up by the headstock adjusting screws. When you get them out, close them up again fully (one at a time) in a vice, preferably a good square machine vice with smooth jaws. Then you can measure the distance between the jaws. Also check at right angles to that dimension, as they may be slightly oval when out of their housings. The average diameter in two directions should be a pretty good measure of the clamped up diameter.

What I am less sure about is how much bigger than this they should be to provide a new lease of life. Not much I think, but the bore should be a little tighter too, so that you recover a small gap when your new slit bushes are installed and adjusted. I think perhaps 0.010" bigger OD and 0.010" smaller ID, but I am guessing.

If the bush is not closing up fully, try to measure the gap with wires and match it when you measure them.

If it does close up, but there is still a gap beneath the clamping parts, you could try widening the slits in the existing bushes to give you some more adjustment.

[steveasub2]

Hi David,
Thanks for the reply.
The slit is still quite wide when in position - about 2mm; it is the clamp that is fully tightened.
Regards,
Steve

[jackrae]

How about this for a get-you-by

Remove upper bearing shell from upper cap
Cut a piece of shim to the shape of the bearing shell contact surface within the upper cap
Place the shim into upper cap
Replace upper bearing shell
Shim should now be sandwiched between upper bearing shell and upper cap

This should now give you a little bit of "pull up" capability. Although strictly speaking the shell bush will not be trully circular it's highly probable that it's already oval in any case. This little bit of adjustment may be enough to get you going.

Many a temporary job is still being used years later !

regards
Jack

[steveasub]

Thanks Jack,
now at least I can keep it going if I can't make the bushes as new.
Regards,
Steve