Myford levelling on industrial stand

Just bought a super 7 on the industrial stand from the classifieds here. It has raising blocks on the tray. Currently the lathe is bolted straight through to the blocks below. It's slightly twisted. Should I be buying jacks or shimming?

I'd start from the floor upwards - make sure the stand is firmly supported with as little twist as possible first, then shim the lathe feet if required, as indicated by the usual test of turning someting and checking for taper. I'm sure somebody will bring up the "it doesn't need to be level" argument, but if you have an engineer's level, that's the easiest way to get in the ball-park to start with.

Rob

No need to spend money on jacking bolts. Shimming works perfectly. And arguably provides a more solid mounting. Cut your shim into a U shape and slide it under the foot around the loosened bolt without removing it.

Bit of info from the ML7 User Manual on how to do a turning test and which foot to shim to bring it into line here. The part about bolting the lathe down without distorting it before attempting to level it or turning test it is well worth noting.

As a rule of thumb on the turning test, if the test piece has taper of 2 thou, I start with a shim of 4 thou under the relevant foot at the tailstock end. The final tiny bit of adjustment can be done by tightening down the relevant bolt without changing the shim. You seem to get a last little bit of movement of the bed that way. You can dial it in dead nuts on this way.

Edited By Hopper on 16/05/2023 09:13:45

Hi,

When I boughtt my Myford 254, I loosened the two bolts holding it down to the industrial stand. I fitted jacking feet to the cabinet and "un-leveled" the stand so Coolant flowed towards the drain hole.

I think your Super 7 should have two levelling grubscrews under the headstock and two under the tailstock. After putting some tension on the two hold down bolts, these grubscrews are used to "level" the lathe.

Gordon

ps Hopper types faster. I'm  not familiar with the  Super 7, but if it has grubscrews, I'd try those before considering shiming.

Edited By GordonH on 16/05/2023 09:28:44

Haven''t seen the grubscrews but if your lathe has them in place, that is a good way to go.

Some lathes have a threaded collar going into the raising blocks and then long studs that pass through the collars into the the bench. You can adjust the collars on these via their hex heads, after slackening off the top nuts on the studs.

I might add too that the principle shown in Fig 19 above about checking the lathe is not twisted when bolted down, also can apply to when you bolt the feet of the bench to the floor. Any gap there needs to be shimmed rather than the bench pulled down under bolt pressure to close it up.

Edited By Hopper on 16/05/2023 09:41:32

There were 2 sorts of raising block, one without jack screws and the other with ! If you have the latter then loosen the main bolts as need be and raise or lower the jack screw, tighten the securing bolt and run a test ! Adjust as found needed until true. You may need a slim spanner to fit between the lathe feet and raising block. The stand should have 4 jack screws to level the cabinet, a spirit level will do this job, first ! Good Luck Noel.

The purp[ose of Riser Blocks is not only to lift the lathe, but allow the lathe to be "levelled" (Mainly twist removed from the the bed, as already described ) Being a screw adjustment, it can be more precise than shimjmking, which can only adjust in steps of the thinnest shim available.

INO, time well spent

Howard

When we got the Atlas 12 x 24, There was a block of aluminium about 40 mm thick and of a good size to raise the headstock end of the lathe. I had two thoughts in mind, to increase the working height a bit for comfort and also to allow levelling adjustment. The tailstock end is now supported on two adjustable supports. The actual levelling has never been carried out and the adjusters are only finger tight as when Rod did some test cuts on large diameter aluminium bar, they greatly exceeded our expectations for accuracy. Just lucky, I presume. This is a sketch of the simple tailstock adjusters which have been posted before, some time ago.

Edited By old mart on 16/05/2023 21:09:31

My lathe is supported on 1/2 UNF setscrews and nuts, to provide a fine adjustment, to remove twist.

That provides for a pretty accurate adjustment.

Howard

We always seem to be talking about removing twist when setting a lathe up, surely we should be talking about not introducing twist by poorly installing the lathe. One would hope that a lathe bed was not twisted when it was manufactured and the casting was properly seasoned before it became a lathe bed. Of course many lathes will have a history by the time they reach our hands and previous abuse may have damaged the bed. I often think a three point mounting could avoid the ham fisted harming the bed but if the bed has developed a twist for whatever reason it would be difficult to correct it.

Mike

Myford Series 7 machine aged raw castings were inverted and the 4 feet machined to a common level.

The casting was then placed the right way up and secured to the machine bed. The top, front and rear ways were then machined to the correct outline before being transferred to a grinding machine when the final profiling took place.

None of the 3 Myfords I possess have been difficult to "level".

If you are making your own raised mounting blocks, a threaded pipe reducer makes a good adjuster, before tightening the throughbolt as required. This enables the block to be bolted into position first, so you are dealing only with the minor variation in height that may be required.

I agree, Mike. Using a level is simply the simplest way to do that. It also makes it possible to use a level to align parts. But I don't think it makes any difference if the machine is placed at an arbitrary angle (within reason of course).

A level is also unique in that you can calibrate it without any special tools or precision references.

I am not sure I entirely agree with Mike about twist in lathes

I agree a properly made lathe bed should be free of twist as it leaves the grinder but the story does not end there. The manufacturer then typically hangs weights ( gearbox on the front and motor on the back etc ) on the bed to make a complete lathe. This can introduce twist in what are really quite flexible castings, and this twist has to be removed by the process we generally call levelling to produce a lathe that will turn parallel.

There seems to be no essential need to make the lathe literally "level" but it is very convenient if one needs to use attachments like milling slides. If the lathe is only ever used for simple turning there is much less need for it to be level but any twist still needs removing.

Rod

Bear in mind that pouring metal into a mould knocking it out, and cooling will introduce stresses.

The outside will cool and contract, while the middle is still hot.

Machining will remove the skin that holds those stresses, so the casting will distort, and may continue to distort after machining ihas ended

Many years ago, castings were left outside for a couple of years for the stresses to work their way out.

Sometimes heating and cooling under closely controlled conditions is usedx for stress relieving. But that takes time, and costs, so in the interests of economy, is not done. (It is hardly practicable in a high volume environment, such as casting and machining cylinder blocks or cxylinder heads for car engines. ).

As an Apprentice in the Toolroom, I spent a Friday afternoon scraping and blueing a machined casting until it was flat, By Monda\y morning, It had distorted, and i had to start again!

Howard

Edited By Howard Lewis on 18/05/2023 09:02:25

As an apprentice, the large frames 6' x 7'x 6' welded up in 2" angle for optical measuring machines were sent away for normalising after welding to stress relieve. Noel

Edited By noel shelley on 18/05/2023 10:10:19

Edited By noel shelley on 18/05/2023 10:11:27Edited to try and remove the idiotic smiley face !

Edited By noel shelley on 18/05/2023 10:13:15