Leveling a Lathe

Hi Guys,

My opinion may be biassed 'coz I own a precision level ( it wasn't when I bought it for a few Quid, but that is another story) but I would not recommend removing twist from the bed by anything held between centres. Logically you have to set the lathe up to an equal level of levelness(?) with a precision level, as you can have no idea how well your tail stock has been set true. Tail stocks generally have a system for turning slight tapers and trying to get rid of twist with an off set tail stock is asking for hair pulling problems. Leave test bars for setting the tail stock for parallel turning. If there is a flaw in my logic I have no doubt that one of you chaps will speak up.

As for twist in round beds (Drummonds), can you not still use a precision level by mounting it on the cross slide and by moving it from end to end of the bed?

chriStephens

I collected the lathe today and have started another thread here with photos and questions.

regards

Brian

Back in the days when I was a lad I well remember operators leanig on their lathe , headstock or tailstock, "to get the cut right" . These were big machines, 2foot chucks. I still don't know if they were pulling my leg, but sounded right at the time.

Here's an interesting way to check for twist when you bolt down a new lathe.

Sit lathe on its bench with mounting bolts in place but not tightened.

Put a steel bar in the chuck, say a foot to 18" long and 3/4" diameter for a Myford/Drummond etc, and tighten chuck.

Put magnetic base on the bed way with dial indicator registering on the far end of the steel bar in about the position the tool would normaly take.

Tighten down the mounting bolts good and tight.

If the dial indicator does not move, you are good to go.

If the dial indicator shows movement, you need shims under one or more feet of the lathe.

Surprising how much movement you get if you don't shim before tightening.

Edited By Hopper on 24/02/2013 11:05:26

Edited By Hopper on 24/02/2013 11:06:21

It does sound odd Gordon (W)for such a large lathe. But quite recently I was in the process of a lengthy series of tasks on the lathe and came to one which needed a very accurate diameter. I was very near the required diameter and taking a very fine cut with a very sharp HSS tool and power fed.

Having been so long on my feet I was becoming leg weary so instinctively leaned on the top of the Myford belt cover only see that there had been a noticeable change in the cut taken. The change was obviously minute but without doubt there. I must get a seat to sit on!

Harold

I got the bench installed today as level as possible using my builders level and will clean up the lathe before installing it on the bench. I have downloaded the user manual for this lathe and the following is quoted from it:

INSTALLATION

It is essential that the top of the bench or stand on which the machine is to be mounted should be perfectly flat and rigid.

When the machine is mounted on the bench, two parallels should be placed on the bed, one on each of the front and rear flats, with an accurate precision level across them. The machine should then be levelled up by inserting suitable packing pieces underneath the feet. This procedure should be carried out first at the headstock end of the bed, next at the tailstock end, and finally in the centre. The machine should then be bolted to the bench.

ALIGNMENT

If at any time it is found that the machine does not turn true, the first thing to check is the levelling, and during the first few months after installation it should be checked frequently.

Levelling of the machine lengthwise is not important, so long as the bed is not twisted through faulty clamping.

Ground test bars should be used for checking alignment.

First check the alignment of the headstock spindle with the saddle guideways, by using a test bar ground to fit accurately in the taper bore of the spindle.

Check on top and on side of test bar with dial gauge.

Alignment of the tailstock can be checked against a parallel bar held between centres, and readings taken in a similar manner.

I will do the best I can with what I've got when setting up the lathe.

Graham,

I think your problem with smileys is that you are putting quotes " next to a closing bracket ) whic produces this ". It might be an idea to leave a space between the quotes and bracket thus " ).

regards

Brian

I have the stand in place and have got it as level as I can using a builder's level. The lathe is what matters of course and that is on the bench at the moment.

regards

Brian