Machin Myford quick change gearbox kit from Hemingway Kits.

[Martin CottrellParticipant @martincottrell21329]

Hi, I'm thinking of adding a quick change gearbox to a recently purchased Myford Super 7. In view of the price/scarcity of the Myford QC gearbox, I quite fancy a go at building the one supplied by Hemingway Kits.

I was just wondering if anyone has built, and/or uses, this particular QC box and what your thoughts are on it? I'm not really after a critique on the kit itself, I'm a long-standing Hemingway customer so know the quality of their kits (usual disclaimer), more interested in the usefulness or otherwise of the finished article.

Cheers Martin.

[Martin CottrellParticipant @martincottrell21329]

[Mat StoeckleParticipant @matstoeckle91130]

I’m in the same boat Martin .. would love to hear from someone who’s done it. I went as far as ordering the plans. It’s involved for a guy like me and my skill level for sure. One “shortcoming” they I could pick up from reading the plans is that the back wall of the QCGB has to be milled down very thin. So much so that the others go as far as saying it’ll keep the swarf out but is fragile. Why exactly that is I don’t know. I’m assuming a space issue. At any rate, would live to hear someone else’s take on it. The idea itself is hugely intriguing based on the fact that you’d reuse your existing change gears for the mechanism

[Mike PooleParticipant @mikepoole82104]

One alternative to a gearbox is an electronic leadscrew which can cut a wide variety of metric and imperial threads as well as any feedrate you may fancy.

Mike

[Mat StoeckleParticipant @matstoeckle91130]

True. I’ve been following Clough42’s videos on YouTube on that subject. But call me old fashioned. I like the good old switch levers and their clunks. Plus I think it could be a cool project to machine.

[Graham Williams 11Participant @grahamwilliams11]

Built a version for my ML7 a few years back after an article appeared in one of the magazines detailing the build of one, bloke named Paine if my memory serves me right. Cut all the gears as well. Few fiddly bits but it's been a really useful bit of kit. The only thing I would say with making the Alum jigs you'll need, not supplied by Hemingway at the time and getting the front info plate made, it didn't work out as much as a saving over buying a Myford box as I hoped. Good project though

[John OlsenParticipant @johnolsen79199]

I made one a few years back for my ML7. It is a challenging project but worthwhile. I had a set of change gears from something else non Myford, but of the correct pitch, so I didn't use the original set. I think this is preferable since you still have them for special setups, and I can use them with my differential dividing setup. I had to rebore and thin those gears. I had to cut some gears as well, but I have all I need for that.

Ideally you want milling facilities, I think you can in theory do all the machining on the lathe, but it is much easier on a mill. Since I have shapers as well as a vertical mill, I was well covered for that.

I've had a few minor problems from time to time, one of the gears shed a tooth at one stage, and the planetary gears for the fine feed didn't stay loctited to the little shaft, but that has a pin now.

As I recall, the back wall does get pretty thin where the clearance for the gears is, but that does not cause any problems. Setting up to line bore the holes is tricky but works out OK.

regards

John

[not done it yetParticipant @notdoneityet]

Quite time consuming, if making all those gears on basic hobby kit? Possibly a job for 3D printing as an alternative?

John, did you cut the gears with profiling using the shaper, as opposed to making cutters for the different tooth counts?

I would expect aluminium gears would likely suffice, so easier to cut.

Still a good, satisfying project, all the same – this from someone who already has a QCGB on his lathe.🙂

[Brian OldfordParticipant @brianoldford70365]

Posted by not done it yet on 24/08/2020 09:19:46:

Quite time consuming, if making all those gears on basic hobby kit? Possibly a job for 3D printing as an alternative?

John, did you cut the gears with profiling using the shaper, as opposed to making cutters for the different tooth counts?

I would expect aluminium gears would likely suffice, so easier to cut.

Still a good, satisfying project, all the same – this from someone who already has a QCGB on his lathe.🙂

Even 3D printed might work OK.

[HopperParticipant @hopper]

I wonder if the less expensive change gears from a Chinese mini lathe etc. could be used if the centre distance between shafts was adjusted to suit?

[Brian WoodParticipant @brianwood45127]

Hopper,

That is actually rather a good idea, the gearbox is bulky with a gear cone up to 65 teeth and the output stage includes a 70 tooth gear. All these are 20 DP

Using 1 Mod mini lathe gears would make a big improvement on those sizes..

I would though use steel gears throughout, replacing printed gears in the gearbox if necessary would be a pain.

Regards Brian

[John OlsenParticipant @johnolsen79199]

I don't think printed gears would be up to the task. I had one cast iron gear in the cluster lose a tooth. The other gears are OK, so it may have been a fluke or a previously damaged gear. If I was making a new set from scratch I would use steel. They are narrower than standard Myford change wheels.

The gears that I made were done with the vertical mill and a Vertex dividing head. I have a full set of 20 DP cutters. Gear cutting is not too bad, I find making up the blanks the most tedious part. Cutting the teeth does require total concentration but does not take long. Felt tip pen marks on the dividing plate help to remind which holes to use.

John

[Bill PudneyParticipant @billpudney37759]

Getting a full set of mini lathe steel change gears from someone like Arc Euro would save a lot of work. Using them on a Myford might cause the Earth to spin off it's axis and plunge into the Sun though.

cheers

Bill

[HopperParticipant @hopper]

Posted by Bill Pudney on 25/08/2020 01:02:51:

Getting a full set of mini lathe steel change gears from someone like Arc Euro would save a lot of work. Using them on a Myford might cause the Earth to spin off it's axis and plunge into the Sun though.

cheers

Bill

😄😄 I might do it just for that alone!

The other advantage would be you keep the full set of Myford gears intact for doing oddball pitches. And you could probably buy the rogue 18 tooth gear in Mod 1 easily enough.

[Bill PudneyParticipant @billpudney37759]

Hopper said…"And you could probably buy the rogue 18 tooth gear in Mod 1 easily enough. "

Another advantage of using the mini lathe change gears would be that "odd" gears would be available from concerns like HPC Gears, without incurring the wrath of your financial advisor, always assuming that the World hasn't been consumed by fire………….

cheers

Bill

[Author]

Posts