Myford Gearbox Manual
Comprehensive Data Packs with Operation Manuals, Parts Lists and. Myford Super 7BPXF - with Screwcutting Gearbox and Power Cross Feed See also 'new. Manual for quick change gearbox no. 712v Ref: 16 This is a manual with instructions for the installation and operation of a quick change gearbox for Nos 1480 (ML7) and 1680 (ML7-R and Super 7). This is a manual with instructions for the installation and operation of a quick change gearbox for Nos 1480 (ML7) and 1680 (ML7-R and Super 7).
I am looking to add a gearbox to my 1948 ML7 and would appreciate some advice. Will a gearbox from an S7 fit?, I understand that the leadscrew on my ML7 would need to be shortened and sleeved up to 3/4' to fit an S7 gearbox and there is a packer between the gearbox and the lathe for alignment purposes, but is there anything else that I need to look out for? The same basic gearbox is used on both machines. If you look here and look for a file 's7gbox2.pdf' this is the fitting and operating instructions which may help you. It's about 35 down in the list, with a red Adobe badge. Edited By Robbo on 19:17:09 Hi there, SteamGeek, As Robbo says, it's the same gear-box for both ML7 and Super 7. I'll check for certain tomorrow but I'm fairly sure that the end section of the lead-screw that passes right through the gear-box to pick up the gear-box output on its left-hand side is 5/8' diameter for both ML7 and Super 7 lathes.
So you won't need to sleeve for an ML7 fit. The threaded part of the lead-screw is 5/8' diameter on the ML7 and 3/4' diameter on the Super 7 machines. What you do need to do is check whether when you remove the gear quadrant and left-hand lead-screw bearing from your ML7, your lead-screw is revealed to have TWO positions for the Woodruff key, early versions only had one. The 'outer' key-slot will be removed when you shorten the lead-screw and the drive gear that picks up the gear-box output uses the 'inner' key-slot. You say that your ML7 dates from 1948 - I'd expect that a lead-screw that old will only have the one key-slot.
So you will either need to machine a new key-slot or procure a more recent lead-screw. The packing strip is not used on the ML7 fit - I think it is required on the Super 7 fit because the effect of the 3/4' diameter lead-screw is to displace the lead-screw axis further from the machine bed than it is on the ML7. If you look on the web-site of the new proprietors of Myford, you will find the Illustrated Parts Lists (aka 'exploded diagrams' ) for the ML7, including the Quick Change Gear-Box. Go into 'ML7 spares', select the assembly of the lathe you're interested in, scroll right to the bottom of the page and click on 'larger diagram'. I haven't looked but I expect the parts lists for the Super 7 are there too.
The Beeston Myford fitting instructions for the gear-box require the lead-screw guard to be shortened to 3⅛'. If the lead-screw you eventually fit is of the two-piece type with a collar at the left hand end of the threaded portion, I reckon 3⅛' is still too long by somewhere between ⅛' and ¼'.
At 3⅛' the end of the lead-screw guard fouls the collar before the carriage reaches the left-hand end of the lathe bed. When you refit the lead-screw guard after shortening, you may need to adjust the half-nut gib-strip - the adjustment studs double as the fixings for the guard! If you're careful, you might be able to remove the 2BA nuts to release the guard without moving the studs. The Beeston Myford fitting instructions don't warn you about that one! Best regards, Swarf, Mostly!
Edited By Swarf, Mostly! On 22:02:58 Edited By Swarf, Mostly! On 22:03:43 Edited By Swarf, Mostly! On 22:06:12 Hi there, again, SteamGeek, I forgot to mention that the gear covers for the ML7 and the Super 7 are not the same. The gear back-plate, however, IS the same.
Best regards, Swarf, Mostly! Hello SteamGeek, Another little tip for you to plan ahead on.
When the gearbox is fitted it covers the access to one of the headstock alignment screws. It would pay you to drill a suitable access hole in the box before fitting. Mine was fitted when I acquired the lathe and I hope I don't need to go there as it means taking off the box to do so. For the benefit of others would you measure the displacement of the two holes please, I for one will make an access hole taking suitable precautions of course.
Regards Brian Hi there, SteamGeek, I have measured the off-cut from my shortened ML7 lead-screw - it is 5/8' diameter. If your ML7 dates from 1948, does it have the mounting holes for the gear-box in the front shear of the bed? Brian, in response to your post: Here is a picture of the Beeston Myford drilling jig for the gear-box mounting holes: I measured the hole-to-hole centre spacings (by putting suitable drill-shanks in the holes and averaging the external and internal caliper readings to eliminate the drill diameters). My results are as follows (from left to right): 1.188', 2.560' and 2.624'. (They look fairly close to fractional spacings.) I am a bit puzzled by Brian's post. The Myford fitting instructions call for the push-screws to be temporarily removed from the lathe bed and their tapped holes to be used to secure the drilling jig. The head-stock casting is held to the bed by the four securing bolts that go in from the top, beneath the mandrel and back-gear cluster.
My understanding is that the function of the push-screws is to position the head-stock casting against the rear shear of the bed until those 'in from the top' bolts are inserted and tightened. Once that is done, surely the push-screws have done their job? The gear-box fitting instructions do call for the push-screws to be re-inserted once the gear-box mounting holes have been drilled and tapped - but they do not call for any re-alignment checks on the head-stock & mandrel. The push-screws may, however, need to be shortened if they protrude from the bed and prevent the gear-box from fully contacting the front shear of the bed. Best regards, Swarf, Mostly!
Edited By Swarf, Mostly! On 10:32:07 Edited By Swarf, Mostly! On 10:34:39 Hi there, again, SteamGeek, To illustrate the point I made about lead-screw key-slots, here is a photo I found: The upper lead-screw is the early type and the lower one is the later type.
You can see from that picture how shortening an early lead-screw loses the key slot. Best regards, Swarf, Mostly! Thanks Swarf, Mostly! The headstock does have some holes bored where the gearbox would fit, some careful measurement this evening and compare to your numbers before I go much further. Need to have a look at the leadscrew and see how many woodruf keys it has.
The guy I bought it off told me it was a late 50's machine, some parts probably are some parts a little older! Fingers crossed for a later leadscrew Thanks Steamgeek Hello Swarf, Thank you for the information, not having fitted the gearbox myself I was in ignorance of those details. Yes then, I agree with you, the push screws are redundant after the headstock is bolted down, but I am still grateful for the information.
If things ever need to be reset, access would be available again. Kind regards Brian Hi there, SteamGeek and Brian, Just to be clear, both the lead-screws in the photo are full length, un-shortened, as supplied with non-gearbox ML7 lathes. Their tail-stock ends are level with each other. Best regards, Swarf, Mostly! SteamGeek, Have just had a look at a 1948 ML7 leadscrew, and that has only one slot, which would be removed if it was shortened.
Also have a leadscrew which came from a gearbox equipped ML7, so is already shortened, and still has the slot. Sold the gearbox and the buyer didn't need the leadscrew as he was fitting it to a Super 7. I would be happy to send this to you in the UK for the price of postage and a pint, should you need it. You don't have a member profile so I don't know where you are.
Phil (in Lancs UK). Posted by Robbo on 14:35:53: SteamGeek, SNIP Also have a leadscrew which came from a gearbox equipped ML7, so is already shortened, and still has the slot. Sold the gearbox and the buyer didn't need the leadscrew as he was fitting it to a Super 7. SNIP Phil (in Lancs UK) Hi there, Robbo, Did your buyer also leave you with the Gear Cover?
SteamGeek will need one. Best regards, Swarf, Mostly! Hi Swarf, Sadly, no.
The cover had been damaged (how they break when you drop a big chuck on them). The repairs to it had left it as a dual-purpose which would also fit the Super 7. Just a few little gaps here and there! Phil Please to post a reply.
Page Title email: MYFORD Screwcutting Gearboxes - early and kit-built types - Comprehensive Data Packs with Operation Manuals, Parts Lists and Catalogues, etc., 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28) 29) 30) 31) Gearboxes and Screwcutting: In standard form both lathes used changewheels for screwcutting and could generate (with the standard changewheel set) pitches from 6 to 112 t.p.i. (or 0.25 to 4 mm). However, both could be ordered (or retrofitted) with a screwcutting gearbox thus becoming, with the addition of a suffix to their model numbers, the ML7B and Super 7B.
The gearbox generated 48 threads from 8 to 56 t.p.i. And the same number of feeds (by the simple expedition of pulling out a double gear mounted on the banjo) of 0.139' to 0.002' per revolution of the spindle. Only an Imperial box was ever offered, metric pitches being obtained by sets of conversion changewheels. However, on lathes sent to America the gear cluster inside the box was modified, 23T gear replacing the 19T gear normally used - the result being that the box could generate North American pipe-thread pitches. Although in the late 1940s a kit-form gearbox had been designed and marketed by L.H.Sparey (author of ) it was not until 1953 that Myford's first effort appeared. Lubricated by an oil-bath it was designed along long-established 'Norton Quick-change' lines with a single-tumbler and a reversible gear on its left-hand face that allowed a change to be made between fine feeds and threads.
Early boxes were fitted with unhardened gears and (hidden under a rounded, aluminium cover) a pair of external gears on the right-hand face (from which the leadscrew drive was taken) but in 1956, from box QC 2495 onwards, important alterations were made - with a change to hardened gears and a leadscrew that was much better supported by being allowed to pass all the way through the box with the drive taken from its left-hand end - so allowing the external gears to be dispensed with. It is worth noting that the Metric Conversion Set for the early box is different - the four gears needed being: 2 x 60t, 1 x 44t and 1 x 52t. Later boxes required five gears: 2 x 60t, 1 x 50t, 1 x 45t and 1 x 63t. The standard Metric Conversion Set was replaced during the 1990s by a different design of slotted quadrant arm on which could be mounted a greater variety of changewheels - and so enabled the generation an almost unlimited number of English, Metric and odd threads and feeds. The Myford gearbox was a beautifully made and very tough unit and, with a supply of lubricant in its base (not something that every maker of small lathes considered important) very reliable. The only signs of wear one should encounter are in the shaft bushes; if the gears show signs of damage then the box must have been mishandled or denied lubrication, in normal use it is simply impossible to wear them out. Supplied as standard with an ML7 or Super 7 the changewheel set comprised: 2 x 20, 25, 30, 35, 38, 40, 45, 50, 55, 60, 65, 70 and 75t.
To cut a wide range of metric threads requires, in addition, just two 21t wheels. Myford Series 7 10 changewheels of all years are 20 D.P.
With a 14.5-degree pressure angle, 3/8' thick with a 5/8' bore and 1/8' keyway. A reproduction of the gearbox mounting template can be found below. Although a kit-form gearbox had been designed and marketed in kit form during the late 1940s by L.
Sparey (author of 'The Amateur's lathe'), it was not until 1953 that Myford's first effort appeared. Lubricated by an oil-bath it was designed along long-established 'Norton Quick-change' lines with a single-tumbler and a reversible gear on its left-hand face that allowed a rapid change between fine feeds and threads. The early boxes (as shown here) were fitted with unhardened gears and (hidden under a rounded, aluminium cover) a pair of external gears on the right-hand face (from which the leadscrew drive was taken) (later boxes had all the gears inside) A data pack that includes the If an owner bought a gearbox kit for an early lathe a template was provided (Part No. 232) to help mark out the position of the holes that had to be drilled and tapped - on later beds these were already provided. The plate was secured to the tapped holes that held the screws used to push the headstock back against its alignment flange and holes drilled through the two centre holes such that they could be tapped 1/4' BSF. The maximum holes depth was 0.625' (though the right-hand hole may break through at that setting), the tapped length 0.500' and drill specified a 0.0204' (i.e. A No.6) A gearbox drilling template in place Designed in the late 1940s by L.H.Sparey, author of the indispensable book ' and a prolific writer on model engineering and model aero engines this screwcutting and feeds gearbox was produced in advance of Myford's own in 1953 - with a surprisingly large number appearing to have been constructed by enthusiastic owners.
Myford Gearbox Manual Perdana
The box economised by using standard Myford changewheels. Featured on the BBC 'Inventor's Club' programme during 1949., right, demonstrates to Geoffrey Baumfrey one of the modifications to his ML7 lathe The WMED screwcutting gearbox - of which nothing is known.? MYFORD Screwcutting Gearboxes - early and kit-built types - Comprehensive Data Packs with Operation Manuals, Parts Lists and Catalogues, etc., 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28) 29) 30) 31).