“Levelling” Warco WM280V lathe

A bit of advice please on trueing up a lathe. I’ve recently upgraded to a Warco 280V and I need to turn a long shaft as accurately as possible. The Warco test record shows parallelism of spindle centre line to carriage movement in both planes to be 0.02mm at 250mm from the chuck. Turning a 25mm steel test bar held only in the chuck, I’m getting 0.04 at 200mm, so I need to take out some twist in the bed. The lathe is on the Warco stand resting on 4 adjustable pads at each end, (see photo), the question is: how to go about the adjustment? I could shim under the bolts fixing the lathe to the stand, or, more likely, use the adjustable feet, what’s the best way of doing this? Leave the headstock end alone and wind one pair of the tailstock end feet out of the way and adjust with the weight on two feet, or something else. All advice appreciated.

Stands are quite flexible so any shimming of adjusting of feet is more likely to move the stand than the stiffer cast lathe bed.

You would be better using tailstock support for long shafts which is likely to give a different reading to a long bar that possibly deflects when held at one end.

My 280 has given good service just stood on a wooden floor leveled with a builders spirit level and for that length I would be using the tailstock for support

I would adjust out the twist by loosening the outermost pairs, using the innermost pairs to make your adjustments then bringing the outermost pairs of feet into contact. You might do the last bit whilst keeping the level at the same end to be sure that you don't impart any unwanted twist.

Looking at the website I think that is a machine that is not intended to be twisted, its feet are too close together at the tailstock end.

That said its just a matter of elasticity, so if you put enough steel in the top of the stand to pull and push the bed against the stand it should move the fraction you want.

Nice feet. I need to do similar with my 1942 South Bend.

In my opinion adjusting the feet will do absolutely nothing. When I got my Warco 290V lathe 3 years ago I packed the stand base so it didn’t wobble on the rough concrete floor and then shimmed the rear tail stock foot area to get the lathe to cut parallel.

Tony

Your test bar is a bit long. Usual recommendation is 25mm diameter and 100 to maybe 150 long. At 200mm you are probably getting some flex adding to your taper when taking a test cut. Try it with 100mm sticking out for a more accurate reading.

That said, if you want to turn a long shaft, you will need to support it at the end with the tailstock centre, which will need aligning to turn parallel, separate from getting the bed parallel.

If twisting the bed to get it to turn parallel, I would shim under the tailstock mounting feet on the lathe bed, not the cabinet base. But the cabinet feet could work too so you could give it a try.

Edited By Hopper on 04/02/2023 23:25:53

As it's new I would also give it a bit of running to bed the bearings in and then check the preload. Mine needed a couple of tweaks in the first few months but since then I've not touched them for years

You also nee dto bear in mind that the test results are for a DTI run along a ground test par which would not have had any cutting forces unlike your turned bar which could have minute amount of flex and be getting pushed against any looseness in the bearings.

Do you have a travelling steady? This is the type of job they are for.

Martin C

The instructions for my Kerry lathe require that the holding down bolts should be barely finger tight and the suppot at each end of the bed is fibre board.

I don't hold with the Myford practice of using an inadequate bed stiffened up by sundry bolts, stands, concrete or floor joists with the added variable of an operator who insists on walking about on the elastic concoction.

Use the tailstock and you will probably need to fine tune that for a job of that length and tolerance. Mark the 12 oclock position on the tailstock centre for repeatability as well and always use the same projection on the tailstock.

Martin

IMO adjusting the feet of the stand is unlikely to be very effective in taking any twist out of the bed.

My 300Kg monster is mounted on six 1/2 UNF setscrews, with nuts above and below the mounting feet to provide adjustment to remove twist.

This is effectively the same means of "levelling" adjustment provided by the Myford riser blocks.

Howard

Thanks for the advice. I agree that shimming under the lathe bed is probably a waste of time, tightening will just distort the top of the stand, whereas if the stand itself is lowered on one side the lathe bed should settle with it. I have now experimented with this, and although the bed looks massive and the whole thing weighs 210kg, lowering one side does have a measurable effect on parallel between spindle centre line and carriage. The advice to shorten my test bar will be followed, but I don’t think a travelling steady will help as it will just follow any twist in the bed in the same way as the tailstock will, this is why it needs to be turned unsupported. I’ve actually had the lathe for 6 months and it’s had a lot of use, but before machining a long shaft I just wondered what was the best way of actually adjusting the twist back to factory tolerance. Thanks again to all.