Myford Change Gear trouble

This topic has 12 replies, 5 voices, and was last updated 23 July 2019 at 12:10 by Mark Gould 1.

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16 July 2019 at 16:39 #419288
Mark Gould 1
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@markgould1
Gents,

We are trying to cut an M10 thread on our S7 lathe. We have a metric conversion set and have installed the slotted quadrant as per Myford booklet. The quadrant has been fitted with the required change wheels.

The problem we are having is with the Tumbler Stud. As per the booklet, it must have 30 teeth. The tumble stack is quite thick as the tumbler gear itself has a flange of sorts. This makes the outer wheel on the tumbler stack stick out too far as it comes into contact with the outer wheel beneath it. It is only supposed to drive the inner of the 2 wheels beneath it. I took some photos to illustrate the problem. It may look ok in the photo but the outer wheel on the tumbler stud is actually touching the outer wheel of the stack below it as it's only supposed to drive the inner wheel of the stack beneath it.

Any help is greatly appreciated,

Mark

Edited By Mark Gould 1 on 16/07/2019 16:40:35
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16 July 2019 at 16:39 #26719
Mark Gould 1
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@markgould1
16 July 2019 at 16:45 #419291
ega
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@ega
Is it just a matter of packing out the new quadrant?

Edited By ega on 16/07/2019 16:47:46
16 July 2019 at 17:07 #419297
KWIL
Participant
@kwil
Yes
16 July 2019 at 17:09 #419299
Martin Kyte
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@martinkyte99762
It looks like you need to fit a spacer between the two change wheels on the quadrent. Myford supply such an item which is used on most wheel set up's on non gearbox series 7 lathes to provide clearence and stop the change wheels rubbing. It looks like a penny washer with a cut out for the key so you can slide it onto the stud. If you have a set of change wheels you should have one.

regards Martin
16 July 2019 at 17:16 #419300
Nick Hulme
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@nickhulme30114
Yes, add spacers, or skim the quadrant to align correctly.
16 July 2019 at 17:24 #419302
Mark Gould 1
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@markgould1
Yes, that is the logical step. I took a short cut and put a washer on the whole stack which moved the whole stack outwards but a spaced between the 2 wheels is the way to go. I'll order the parts from Myford.

Thanks gents!

I told my Dad we'd have the answer inside 15 minutes, you gents are fantastic, many thanks from Dad and myself
16 July 2019 at 17:53 #419314
ega
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@ega
Glad to help and to know who the "we" are!

Although I have a shop-made equivalent of the Myford conversion set, I mostly just "play tunes" on the stud gear in the way that has been frequently mentioned here. Brian Wood's book is recommended on this topic.
16 July 2019 at 23:03 #419357
KWIL
Participant
@kwil
Before you leap to any further conclusions.

Consider if the Anchor Pin, part no A3015 Dwg Ref 203 is correctly assembled into the base of the gearbox. Its depth is set by a single Socket Setscrew (from below). If correctly set this is what hold the quadrant in the correct position to ensure the gears do in fact properly align, without adding any spacers to the gear train.
17 July 2019 at 23:28 #419557
Mark Gould 1
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@markgould1
Good point, KWIL, many thanks I will certainly do that next time I am at the lathe. I didn’t even know there was a pin down there.
17 July 2019 at 23:32 #419559
Mark Gould 1
Participant
@markgould1
Ah I now know which pin you mean. I wasn’t aware that pin was only held in by a set screw. I just had a look at a pdf I have here on my tablet and see it how that could cause this issue.

thanks again, excellent.
17 July 2019 at 23:32 #419560
Mark Gould 1
Participant
@markgould1
Ah I now know which pin you mean. I wasn’t aware that pin was only held in by a set screw. I just had a look at a pdf I have here on my tablet and see it how that could cause this issue.

thanks again, excellent.

Edited By Mark Gould 1 on 17/07/2019 23:35:21
23 July 2019 at 12:10 #420514
Mark Gould 1
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@markgould1
KWIL,

Just getting back to what you said, it's actually in the manual that I have. Makes it all the more embarrassing that I missed it, duh!

Mark
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