Gearbox for Myford Super 7

[timo]

Hi,

Has anyone tried fitting an L.H. Sparey gearbox to a Super 7? It was designed for the ML7 but I am not sure what issues would be faced fitting one on my S7. I know the leadscrew will have to be shortened but is there anything else? The gearbox was designed in 1950 so it pre-dates the S7 and indeed Myford's own gearbox.

Thanks

Tim

[twombo]

Tim

Researching Hemingway site just now and I see The S7 mentioned as tho it may be adaptable. The plans and instructions may give more Info! I would love to have a Myford and be contemplating a quick change gearbox! The supply of Myfords in the U.S. is very sparse. I have contemplated building one from parts. I built a 9” south bend with power crossfeed over 10 years, from a near perfect bed. Having the advantages of a Myford, is a worthy goal. Possibly, quite crazy! The specialized accessories are Very attractive!

Mick

[timo]

Dear Mick,

Thanks for the message. I already have the plans and instructions for the Hemmingway gearbox. It uses several large castings which are quite expensive and if you buy the castings plus all the gears you are up in the £200 - £300 area plus you then have to machine everything. The reason for the question was that there was a Sparey gearbox on ebay at a very reasonable price. The sparey box though was designed some years before the S7 was launched so I wondered if anyone had actually fitted one to a S7. By the time I had done research (I didn't find out!) it had been snapped up by someone else. I do have the original articles on making it so I may well go back and re-consider it.

Best Regards

Tim

[twombo]

Thanks for the reply , Tim! I understand and support your prudent nature. I have been bitten by a couple ‘Impulse buy “dogs” along the way. Good hunting on a gearbox, as they are. Such a nice. Addition. I had a 10” South Bend at my disposal for some years, through my employer. I have yet to find such a Gearbox in suitable condition for my Lathe. The fox hunt continues! In the meantime, most that threads I single point, are 32 tpi, so I can do most of my turning without a change. A very sharp tool with a generous radius, carries me through the jobs that require a fine finish. It is a bit of a ‘dodge’

Cheers!

[timo]

Twombo,

Thanks for the message.

I really want the gearbox so that I can easily select different slow feed rates plus the odd screw cutting pitch. I am thinking of collating my research into a post listing all the options for Myford gearboxes and of course keeping eyes and ears open for a gearbox. Trouble is that you don't NEED a gearbox if you have a full set of changewheels, it just makes it convenient and a gearbox can easily cost the same as a complete set of castings for a loco....

Best Regards

Tim

[uuu]

I can offer an alternative idea. I wanted to easily select slow feed rates too, but was less interested in screwcutting. John the Pump and I devised a electro-mechanical leadscrew clutch (for the Super 7 I no longer have):

Jessie26 by Wilf, on Flickr

The idea is that you can engage/disengage the leadscrew electrically - so you can leave the half nuts engaged as you cut up to a shoulder, so you don't lose the index reading on the handle end. You never strip down the train of gears - changing the feed rate requires only the one input gear being changed, so is very quick. The downside is that the whole thing has to come off to put the normal banjo back on for screwcutting

Let me know if you'd like a look.

Wilf

[timo]

Dear Wilf,

That looks really interesting. Yes I would indeed like a look please. Am currently on holiday, back in a week or so. Can I PM you when I get back please?

Best Regards

Tim

[dscott]

I have a couple of big and very small Myford gears on my shopping list ready for the Midlands Exhibition.
The finest feed will be fine for most of us as I have not done any Screwcutting since I built my home made lathe!!
These days ready made multistart threaded bar is easy to buy and with nut!

David and Lily.

[ivattlms]

Sept 15, 2019 15:38:02 GMT uuu said:

I can offer an alternative idea. I wanted to easily select slow feed rates too, but was less interested in screwcutting. John the Pump and I devised a electro-mechanical leadscrew clutch (for the Super 7 I no longer have):

Jessie26 by Wilf, on Flickr

The idea is that you can engage/disengage the leadscrew electrically - so you can leave the half nuts engaged as you cut up to a shoulder, so you don't lose the index reading on the handle end. You never strip down the train of gears - changing the feed rate requires only the one input gear being changed, so is very quick. The downside is that the whole thing has to come off to put the normal banjo back on for screwcutting

Let me know if you'd like a look.

Wilf

[ivattlms]

I am interested in your idea any sketches etc thanx

[boldford]

An alternative worth considering is the Clough42 Electronic Lead Screw as featured on a series of YouTube videos.