myford running out

[Stephen GillParticipant @stephengill79322]

hi hope some one can help when turning longer pieces on my super 7, it is not cutting straight. the finish is perfect apart from the 6/8 thou taper over 150 mm any advise will be appreciated.

[JasonBModerator @jasonb]

Are you using tailstock support?

[peak4Participant @peak4]

It’s a subject that comes up very often on this and other forums.
Well worth a search on this site for “Levelling a Myford Lathe”

This thread/Topic is as good a place as any to start; it includes a couple of useful book titles, as well as the relevant pages from the Myford manual.

Have a read, and make sure that you appreciate that the term Levelling, in this context, doesn’t necessarily involve the use of spirit levels, or the lathe actually being horizontal.

Having the bed horizontal does have advantages for some setups, but not in relation to turning parallel.

Having the cabinet sloping, may be advantageous so that any coolant drains to the correct place.

Bill

[Roderick JenkinsParticipant @roderickjenkins93242]

Stephen,

Myford 7 series lathes need ” levelling”, an unfortunate term that can lead to misunderstandings.

There is a nice website here that describes the process succinctly

http://www.steves-workshop.co.uk/tips/lathesetup/lathesetup.htm

Hope this helps,

Rod

[Howard LewisParticipant @howardlewis46836]

As Rod says, the problem may be that the lathe is not “level”, ie, the bed is slightly twisted.

The way to cure this is to secure the feet at the Headstock end of the lathe and to adjust (IF you have Riser Blocks or something similar) or to shim the feet at the Tailstock end.

Ian Bradley’s “The Amateur’s Workshop” or his “Myford Series 7 Manual” tells how to do this.

The process is sometimes known as “Rollie’s Dad’s Method”

This requires a workpiece to be turned and carefully measured.

It is applicable to almost any lathe, to remove twist from the bed.

If you are turning between centres, the tailstock needs to be aligned with the Headstock, to prevent taper.

(Offsetting the tailstock is a known method of deliberately turning a long taper).

Ideally use an Alignment bar and DTI, (For this the lathe should not be rotated once the clock has been set to Zero at one end.

if not, by turning between centres, and adjusting the Tailstock body across the base, until the taper is eliminated. “Suck it and see” can be slow and frustrating, but should result in an improvement.

Mount the soft centre in the 2MT Headstock taper (Free of bruises/burrs) , offset the Top Slide by 30 degrees, and trim up the taper.

If you have a 4 jaw chuck, you can make an Alignment bar; it won’t be bigger than 1/2″ , maybe 13mm, because that is about the largest that will pass through the 2MT Headstock.

Ideally use Silver Steel.

Set with minimum protruding from the 4 jaw.

Clock until running as true as possible (< 0.0005″ / 0.0127 mm) face and centre drill.

Reverse, and repeat

Hopefully you will now have a 1/2″ (or 13 mm)  diameter, 13″ long Alignment bar with better than 0.001″ (0.0254 mm) total runout, between centres, which should suffice for most purposes.

The less the run out at each end, the better the bar, so the time spent in clocking true will be well spent.

Howard

[Stephen GillParticipant @stephengill79322]

Thanks for the answers spent some time adjusting for twist now almost perfect thanks again steve

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