Myyford gearbox strip down

[Stephen ChaplinParticipant @stephenchaplin32867]

Sadly whilst moving my super 7 it toppled over onto the gear box selector and broke the lever. I'm now struggling on how to remove it for replacement. I've taken the box of the lathe, the shaft is free but because the gear on the lever sits in the machined slot it won't come out. I can see a taper pin in the gear, but how do you get to it to either tap out or drill out. I've also removed the top selector gears to give more access but a loss. Help please.

 

Stephen

Edited By Stephen Chaplin on 15/01/2021 14:19:19

[Stephen ChaplinParticipant @stephenchaplin32867]

[Swarf, Mostly!Participant @swarfmostly]

Hi there, Stephen,

I'm very sorry to hear of your lathe's mishap.

Do you have the Myford User Instructions booklet (that's not its proper title ) ? There are 'exploded diagrams' dealing with the major assemblies comprising the ML7 or Super 7 (it's the same gearbox for both lathes) .

If you don't have the booklet then the exploded diagrams and parts lists are available in down-loadable form on the Myford web-site.

To give would-be helpers here something to work on could you take a few photos and up-load them here?

Best regards,

Swarf, Mostly!

[Stephen ChaplinParticipant @stephenchaplin32867]

Thanks for your response, I do have both user guides, but although the diagrams show the components no explanation as to how to remove them sadly and Myford were no help. I'll willing add pictures, just not sure how, so any guidance taken.

The only way I can see this pin could have gone in was with the shaft and gear in place, many, many years ago

[Stephen ChaplinParticipant @stephenchaplin32867]

[Stephen ChaplinParticipant @stephenchaplin32867]

[Stephen ChaplinParticipant @stephenchaplin32867]

[Stephen ChaplinParticipant @stephenchaplin32867]

Worked out , these show the broken selector and the pin from both ends

[john fletcher 1Participant @johnfletcher1]

Hello Steve, several years ago I also had Myford G/box problem, on an early type, I bought the lathe and after some months found out one or more gears were broken. I contact Myford at Beeston regarding replacement and they said we don't stock them any more. I had a HPC gear manual and found they did, but the bore was larger, so shrink fit was required and the price was a pleasant surprise as well. I hope you will soon have your lathe back on the road now you have got the shaft out. John

[Ady1Participant @ady1]

If you're able to do the job then that's great but if you can't then the gasless mig welders seem to have no problem glueing cast iron back together

I tried to break a big old vice I had broken and mig-repaired and couldn't do it

So for a non-critical job like a lever, a mig and 5 minutes of welding might be easier

you just hold the part in place and zap it with a tack weld. then do the job

Edited By Ady1 on 15/01/2021 16:06:52

[Stephen ChaplinParticipant @stephenchaplin32867]

I was going to get it welded, just was trying to take it apart to do that. I may ask the guy if he will do in situ, just don't want to damage the box with the heat. May save the pain of trying to get the in out

[Ady1Participant @ady1]

My unit doesn't go over 140Amps, its a cheap lidl job

I do nearly all my heavier jobs on a mid setting which is 70-110 kinda thing

edit, you're not after a full depth pro weld, just a good fix

Edited By Ady1 on 15/01/2021 17:05:39

[Glyn DaviesParticipant @glyndavies49417]

The taper pin seems to be in a through hole, not a blind one, so why can't you drift it out from the small end? Maybe take out the gear cluster shaft with the long key in it from the right hand end to get some more room. They put it together, so it must come apart!

[Stephen ChaplinParticipant @stephenchaplin32867]

Downside with that approach is there is a dam taper pin in that cluster as well and I so don't want to do that one as well. The challenge is holding the lever and the gear still whilst using my third hand to hit the drift with the hammer. Id love to know how Myford put them together.

[Stephen ChaplinParticipant @stephenchaplin32867]

Downside with that approach is there is a dam taper pin in that cluster as well and I so don't want to do that one as well. The challenge is holding the lever and the gear still whilst using my third hand to hit the drift with the hammer. Id love to know how Myford put them together.

[Rod ClemettParticipant @rodclemett60985]

I'm wary of making a 'couldn't you just…' suggestion, but couldn't you just slide out the big shaft that the selector lever pivots on, and lift out the lever complete with that gear still attached?

Clem

[Stephen ChaplinParticipant @stephenchaplin32867]

Ah, when i started the whole process I thought that was the plan, the bit that's not seen is the bottom of the sleeve is open, the shaft that goes through it is splined, the gear from the lever then meshes, the trouble is the gear overlaps the slot. Oh bugger was a couple of the words mentioned,

[Glyn DaviesParticipant @glyndavies49417]

These gearboxes are so beautifully made that I don't think any part needs much force to dismantle. Put the inner shaft with the long spline back and refit the input gear and use that gear to stop the pinned gear rotating. I think the pin In the gear cluster shaft will knock out easily.

[Rod ClemettParticipant @rodclemett60985]

Does the pin align with the drain plug hole at all, to give clearance to knock it out?

The reason I'm wary of the 'couldn't you just….' suggestion, is that in my experience those who make them usually haven't fully grasped the problem. I see that I was no exception! Sorry!

Clem

[Stephen ChaplinParticipant @stephenchaplin32867]

Hadn't thought of that, no need for 3 hands. I knew someone would have the answer. Ill keep you posted. Thanks

[Robert ButlerParticipant @robertbutler92161]

Many years ago I retrofitted a QCG to my ML7, now sold. I stripped the gearbox completely down to the last nut and bolt and cannot recall any difficulty in dismantling and rebuilding. The main shaft may have to come out first which will give access to the shaft where the selector is located and the shaft should then slide out unless I am missing something?

I think the problem is trying to partially dismantle the gearbox. I don't recall the job taking very long either, it took longer to clean the parts and dry them than the strip and rebuild.

Robert Butler.

[noel shelleyParticipant @noelshelley55608]

I have the exploded diagram. On the rthand is a grub screw and collar, nos 184 and 185. On the left is the input shaft 183 and gearwheel186 secured by a nut &washer 188/167 – remove, don't loose the key 166. there is a tube 179 ! It looks as though the tube and long gear shaft 186 should remove from left to right. There might then be room to lift out the taper pinned wheel and lever. As to repair, grind out, and use a nickel rod in MMA, not cheap but run like butter or braze. Good luck, Noel.

[Stephen ChaplinParticipant @stephenchaplin32867]

I've attached a picture I'd the shaft and the cut out from the myford site so you can understand the missing part of the removal challenge.

[noel shelleyParticipant @noelshelley55608]

Hi Steven, That's The long gear shaft 183. I do not have a description of the parts and the No s but it looks simple enough. Put away safe somewhere is the instructions for fitting this box to the lathe, I will see if I can find them, it may help. Good luck Noel.

[Stephen ChaplinParticipant @stephenchaplin32867]

This the picture in the tube showing the challenge with the gear on the selector.

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