Myford Super 7 quick change gearbox fitting

I’m toying with the idea of fitting a myford super 7 quick change gearbox to my myford ML7 .

What modifications would I need to make if any ?

Thanks in advance .

If you have the end covers and lead screw with the gearbox you shouldn't have any issues.

Not sure about ML7s but you have to change the output gear on the tumbler if retrofitting a gearbox to the Super7. You will probably need a shim between the gearbox and the mounting point on the bed. As far as I know, the shim is needed on all lathes except the PCF models.

Hi there, Kevin,

Do you have the installation Instructions for the gearbox? If not, I suggest you obtain one and read it. (I believe they are available on-line, maybe from the 'Files' section of the of the Yahoo Myford group. )

Does your lathe have the necessary tapped holes (¼" BSF ) in the front shear of the bed? They are between the two holes that have the push-screws that push the head-stock against the back shear. Some early lathes didn't have them, mine included, so I had to drill and tap them. Beeston Myford used to offer a drilling jig for this purpose, though they denied all knowledge when I phoned until I was connected to the late lamented Malcolm - he found me one. You temporarily remove the push-screws and use their tapped holes to hold the drilling jig.

The gearbox has a third screw at a lower level - that fixed into an existing tapped hole, from memory, one that previously held the left-hand lead-screw bracket.

Best regards,

Swarf, Mostly!

It’s all there apart from the lead screw .

Thanks for the replies .

Kevin I have the jig and instructions somewhere? Robert Butler

In that case, won't you will have to modify, ie shorten, your existing lead screw?

That was the case when I fitted my Boxford "B" with a gearbox. Fortunately the leadscrew passed through the spindle bore, which allowed machining of the end. Will this be the case for a Myford?

Doesn't the Super 7 have a larger diameter leadscrew than the ML7 ?

Edited By roy entwistle on 04/11/2018 19:45:04

Kevin I have found the jig, the instructions as to how to fit, modify the leadscrew and clasp nut carrier are all contained in the Myford Quick Change Gear Box supplement. I would expect as the shears are not tapped for the gearbox it is an early model ML7 and has the small diameter leadscrew. I have a spare small diameter leadscrew as well

Robert Butler

Thanks Robert , if I buy the gearbox , I’ll be in touch with you .

Edited By Kevin F on 04/11/2018 20:08:50

The ML7 lead-screw is 5/8" diameter, the Super Seven lead-screw is 3/4" diameter.

However, the left-hand end of the 3/4" lead-screw for use with the gearbox and Super Seven is reduced to 5/8" diameter so it passes through a bore in the gear-box casing. The coupling sleeve between the 3/4" and the 5/8" sections is secured with two roll-pins - it fouls the lead-screw guard attached to the saddle so one of the instructions is to shorten the lead-screw guard. I had to shorten mine by about 3/4" more than specified to avoid losing saddle travel.

Later models of the ML7 lead-screw (non gear-box version) have two Woodruff key slots so you still have one after you've shortened the lead-screw. Early lead-screws only had a single Woodruff key slot.

Best regards,

Swarf, Mostly!

I have a Super 7 and flirted with the purchase of a QCGB but thank God I didn't, I now have to cut lots of oddball Metric pitches that would involve as much messing about with a gearbox as without and allow me a full range of Metric and imperial pitches without approximations.

According to a drawing I've found on thinternet, using the existing left hand tapped hole as reference, the first tapped hole for gearbox is 1.88 inches to the right, and the second 3.748 inches from the reference.

They seem to be very odd dimensions. Could somebody confirm please?

Gordon.

It's only a guess, Gordon ... but I suspect that the design dimensions are

1.875" and 3.75"

which would be instantly recognisable as convenient fractions.

If the drawing was "made from life" the difference is probably due to either manufacturing tolerance, or poor measurement.

MichaelG.

What you say Michael makes sense, I should have realised this. My excuse is brain fade from late night posting following daughter's 30th birthday celebrations!

Thanks,

Gordon.

Excellent excuse, Gordon

MichaelG.

Can't help with ML 7 but converted S7 which required new banjo , leadscrew , change wheels and cover.

The instructions from Myford help. Nick I have no problems cutting both metric an imperial threads with the QCGB, only needed to purchase a few extra changewheels as per Brian Woods book.

Hugh