Early myford super Seven parts identify plz

Hi Piero, I think the best answer to your question about where do the bits fit is to suggest you need a copy of Brian Wood's book, Gearing of Lathes for Screwcutting, which gives chapter and verse on the subject. ARC have copies, and so did Amazon the last time I looked.

Essentially the gear train that carries the drive from the lathe mandrel down to the gearbox input gear is removed, and replaced with a selection of gears of different tooth numbers, all as per the appropriate label as above.

The standard banjo on which the gears are mounted isn't slotted, so this limits you to only using the original gears. To be able to use others (as per the label) you need the gears AND a different banjo. The one that Myfords sell, and which has been called the "Metric Conversion Kit", fits in place of the standard gear mounting carrier and allows change wheel trains to be built up in much the same way as you would in the old days before the quick change gearbox was invented. The difference here is that the slotted "Metric conversion kit" banjo lets you keep the quick change gearbox AND change the input ratios. That's what the labels above are showing.

The other half of the metric adaptor kit is a selection of change wheels of some funny looking numbers, as detailed on the labels above. If you would like to list the wheels you've got lurking in a box we can tell you what you can do with them, and whether they belong as a set with the metric conversion kit. (And for which version of the Q/C gearbox!)

Brian's book explains in more detail.

Myford users being inventive so - and - so's, along came the idea of keeping the original fixed spacing gear carrier, and changing the input gear (mandrel gear) to adapt the ratio between the mandrel and the lead screw. It happens that an extremely close approximation to the "correct" ratios can be achieved for a wide range of metric pitches just with a small handful of input gears. For the later gearbox, most of the metric pitches you'd likely want are achieved with a 33T and a 34 tooth gear, mounted on the 10351 tumbler adaptor as detailed above. John Stevenson pioneered this, and the gears to do it need are available from Myford. But it doesn't work for you and me - read on.

The big advantage of this technique is that you get to keep the fine feed ratios. If you fit the "metric kit" you lose the facility of the fine feed. The metric pitches you get are an approximation to the "true" metric pitches, but that's also true of the pitches you get with Myford's metric adaptor kit. Some of the approximate results are actually better than the original design, and (as Brian's book examines) you need to consider the limitations of the lathe's accuracy as well.

For your lathe - and mine - this doesn't work, as the early gearbox does not have the built in 2:1 speed reduction of the later gearbox, so if you set up the gear train as for the later box you cut a thread of twice the pitch you expect.

All is not lost, we know how to fix it. If you want to get involved with this we can explain further, but you really need to see Brian's pictorial explanation of what is going on first, as the adaptations to make it work with your earlier gear box assume an understanding of the overall system and also some rather creative gear cutting which John Stevenson devised.

Hope this makes sense,

Rgds Simon

Hi Piero,

The early "Metric Conversion Set" for the gearbox you have consisted of 10 gears as follows: 20T, 30T, 35T, 40T, 44T, 45T, 52T, 55T & 2x60T. If you have these in your box then you have the early set. The pictorial supplied by Simon and which you have on your changewheel door is the correct one for your lathe, but the conversion set that you have may be a later set for the newer gearbox. As further clarification the only difference between the two sets is in the gear selections, all the other parts stayed the same.

The later set consists of 12 gears: 28T, 30T, 35T, 40T, 2x45T, 2x50T, 55T, 2x60T, 63T. With my set of later gears in its box, I have supplemented the set with additional cogs and any previous owner may have done the same or similar with the set you now have. My choice of my extra 6 cogs gives me all the options for any thread using the early gearbox.

The use of the metric quadrant is fully explained in the gearbox manual, most likely page 6, along with a pictorial of all the parts you should have in the box. The parts list also shows the Conversion set pictorial and if that fails the Myford site has it for free under gearbox. The washer and shaft in your pictures should be in the box and probably the two cogs as well if there are spaces in the cardboard cutouts for them to fit. There is nowhere in the box for the tumbler sleeve gear. Note that as already explained, the ratios in the later gearbox manual do not work on your gearbox.

As an additional note, The early "Metric Set" on the early gearbox did not give as accurate threads as the later combinations.

Hope that helps

Dennis

Once again many kind thanks for your help

Its probably been said before, but people with learning difficulties normally prefer to ask questions specifically to there need,

its quite a task reading a mound of stuff (if you struggle to read) in order to find that one bit of info you need.

I was born dyslexic and asking questions works better for me on the whole,

sorry to others who have read this TYPE of gearbox topic before.

If its ok, Id like to take some photos of my metric gear set and post them on my blog for you to see,

wont get that done till tomorrow now.

Once again, many kind thanks for all the input and help

O and thanks spell check LOL LOL

just added two photos and a description under each photo.

some gears are doubles, this can be in a different tray

As well as the banjo, the two shafts and two spacers, I have gears with teeth off

28t 28t (as in two of the same) 60t  60t (two of the same) 65t 25t 45t 63t 35t 38t 45t 50t 50t (two of the same) 55t and a lose as in not in this box set of 40t

Edited By Piero Franchi on 01/12/2017 12:17:05

Hi Piero,

1) No new photo's on this site. Have you put them in Photobucket or something else?

2) Your stated list of gears is not a Myford one I recognise. You have listed 45t twice separately, is that an error? Your list does not fit the non-gearbox selection either.

3) A picture of the banjo may reveal what the set belongs to. Is there a label one the box? Is there a number on the box?

4) You stated at the start that the 30t was 1/2" wide. Are they all 1/2" wide? Myfords are 3/8" wide.. Do they have a keyway cut? Are there any holes in the gears near the middle besides the centre hole?

5) Have you obtained a replacement leadscrew and fitted it?

6) Have you rebuilt the gearbox and had it working?

Is there anyone near this chap in St Albans willing to help him out?

Regards

Dennis

Hi Dennis

For some reason the photos would not show in the album, when I went to edit it, they were there,

went back out of the album and they were gone again, uploaded two more photos to this album and they dissapired again,

so I deleted the album and done a new one, this times it all seems ok

I had taken a photo of the part number (but obviously that didnt show either) but its there now

rebuilt the gearbox (you can see this on one of my albums) and its all working as it should.

To be honest, I have never had a problem taking stuff apart and putting it all back togeather again, it comes quite natural to me, 

Its the stuff I have never set my hands on that I could do with the help on 

Piero

Edited By Piero Franchi on 03/12/2017 17:30:35

Hi Piero,

Well you have a later Myford Metric Conversion Set there. The label clearly states part number 1481/1 but also mysteriously states "For QC2495 and onwards". "QC" stands for Quick Change. I have always understood that gearboxes from QC2501 were the later pattern.

Anyway, you have the later gears set which is not ideal for your gearbox. I think you may have counted teeth wrongly, for instance the one cog in the layer with the change gear quadrant (or banjo) I believe is 30t. and you list 2x28t and no 30t at all. There is only one 28t in the set and unlikely to be use for 2. However, my set only consists of 12 gears and your set has 14 but, as I said before, some gears may have been added and there is evidence of different paint colours!

To cut metric threads with some accuracy you replace the fixed gear set inside the changewheel cover with the quadrant in the box. The circular hole in the quadrant fits over the gearbox input shaft. The two shafts in the layer with the quadrant need fitting first (remove the nut, sleeve and washer first) as they go into the back of it. All is clear if you have the pictorial of the quadrant that I stated in my previous post of 28 Nov.

Do you actually have the 12 gears that I listed in that post? If so, how many teeth do the other two gears have? Another complication to answering your problems is that my Metric Set is on three layers in its (original) box, but the layer with the quadrant is the same as yours. Do all 4 layers fit inside the original Myford box or do only 3 layers fit? We could talk about this better if you PM me your e-mail and I can supply tables of cog set-ups which will work for your gearbox. But you do need a few extra gears to be able to cut all threads.

Lastly, your opening question and pictures included a washer with a keyway cutout. There should be two of those included in the set, 50thou thick. The shaft in those pictures may be the same as the 2 shafts in the layer with the quadrant piece, and if so is a spare. The 30t in the pictures is not Myford if it is, as you stated 1/2" thick. Do not be tempted to try and use it with the metric set.

Dennis

+1 on Brian Wood's book "Gearing of Lathes for Screwcutting". I just got my copy and it goes into quite clear detail on the various gear trains to be used with Myford QC gearboxes to either convert metric to imperial, or imperial to metric. Also to cut BA, Holtzpalfel (sp?) and metric and imperial worm threads to match standard gears.

It is I believe the definitive book on the subject.

Gearing for all alternatives is laid out in easy-to-read charts. So that might be easier for you.

My Metric set has four layers (as stated by DMR)

they all fit into its original box, so I would guess it was a four layer box set.

The gears I have mentioned are correct as to what I have in the box set.

Yes there is always a chance some of the gears have been lost and others added.

I am defiantly going to be looking into purchasing the Brian Wood book on gearing.

I am relying here on the forum rather than by personal email ONLY incase there is important information shared here that could help others.

If you (DMR, or any other) wish to send anything outside of this topic, plz feel free