Myford G/Box Gears help.

Hello Everybody,

Yesterday I wanted to cut a 1mm pitch thread with my Myford Guick Change G/Box, Metric Conversion Set.

To my horror I discovered I did not have a 63 tooth gear needed, however in the box containing all the parts every cavity had a gear in it, and when I purchased it second hand I thought it was complete.

Also strangly enough the Myford G/Box booklet mentions "12 changewheels",

I have twelve plus a 30T with the quadrant?

I have shown my gears in the photos included.

Could anyone please advise me which ones do not come with the set and what are the ones missing from the set.

I realise from the charts in my booklet I do need extra gears to cut

Diametral Pitches, Module Pitches and BA Pitches, which I will acquire as I need them, however I would like to make my box set complete as sold new.

40T, 45T, 55T

50T, 50T, 35T

60T 60T.

60T 65T

45T 28T

Quadrant 30T

Thank you for looking.

Brian Wood, author of the excellent book Gearing Lathes for Screwcutting posts on here regularly so can probably tell you exactly what is going on when next he checks in. But a quick look at my copy of his book shows no mention of a 63T. He lists for a 1.00mm pitch a 34T mandrel wheel with the gearbox set to 36tpi. Probably no easier to obtain than a 63T though!

Myfords website lists teh following for metric conversion gears. Looks like your set has had a 65T substituted for the 63T.

METRIC CONVERSION SET 1481/1
Set comprises of:
1 x Changewheel Quadrant
2 x Spacers
2 x Changewheel Studs
1 x 28T Change Gear
1 x 30T Change Gear
1 x 35T Change Gear
1 x 40T Change Gear
2 x 45T Change Gears
2 x 50T Change Gears
1 x 55T Change Gear
2 x 60T Change Gears
1 x 63T Change Gear

Also included is the Metric Pitches nameplate

Edited By Hopper on 17/07/2018 04:24:49

Edited By Hopper on 17/07/2018 04:27:14

Hello Noel,

Thank you for the vote of confidence Hopper; I am afraid the missing 63 tooth wheel jiggers up the whole suite of metric ratios that the conversion set aims to achieve. As Hopper says, the use of 34 tooth wheels and other gearbox ratios provide another route and these are listed in my book.

To get over your immediate problem fit the 65 tooth gear in place of the 63 on the Myford quadrant assembly picture on page 6 of their booklet on the gearbox and use a 35 tooth gear as the mandrel driver. Set the gearbox up to give 14 tpi [ settings 8 A] and you will get a pitch of 1.032 mm. It isn't perfect of course by a fairly large error but if you have a die to run down it at the closing stages it may serve for your purposes.

You will though need the 63 tooth gear to complete your set now that you have it; try RDG or Myford for supply

I hope that gets you out of your current hole

Regards BRian

Thank you both Hopper and Brian Wood.

I am making a shaft for a gear cutting head on my vertical slide,as I want to turn and cut without moving the gear.

I designed it with a 25 x 1.0 pitch thread as I advised above.

What I did was just change the thread to a 26 tpi, as I had to make the nut as well.

I seem to have an extra 60 and 65 tooth gear.

I will replace one 60 for the 63. Thank you for the packing list of gears.

I can keep the 65, as its can be used for cutting Diametral Pitches of...

23, 25, 27, 30, 46, 50, 54, 60, 92, 100, 108, 120.

What an exceptional little gearbox it is.

Thank you

Noel

My first thought, I checked that from the photo Frances, it is 65 T, It would seem to have been badly packed at the factory. Myford used a 65 casting blank to cut the 63 T gears into it and whoever packed the kit got it wrong.

It is a nice little gearbox, beautifully made

Regards

Brian

Well, well, well!

Thank you Frances and Brian,

Just ran out and counted the number of teeth, counted 63.

You are right Brian, it is cut from a blank with 65 cast into the relief. It has 63 stamped on the reverse, I didn't take it out of the box as I was in thread cutting mode...

I will have to clean them up, the set was never used and have some corrosion on the faces.

Thank you

Noel

Hello Noel,

All's well that ends well then, the patches of corrosion and poor focus made it less easy to follow a tooth count on an expanded view. I thought I had it right.

Regards

Brian

Noel,

Have a look at this link on the forum its a way of cutting metric threads without using the metric conversion set, a couple of "none standard" gears are needed but easily obtainable from Myford.

**LINK**

Hope this helps John

Here's another link https://www.model-engineer.co.uk/forums/postings.asp?th=121000 

Edited By JohnF on 17/07/2018 17:13:50

Edited By JohnF on 17/07/2018 17:14:13

And eloquently described in Brian Wood's book "Gearing of Lathes for Screwcutting" (which is interesting reading in its own right). Last time I looked Amazon had copies, also ArcEuro.

Rgds Simon

Hi Simon and John.

Thank you everybody, loved the response, help is not so far away after all...

Here is a pic of the 65 casting used to cut the 63 tooth gear.

A trick I am now aware of.

This is the 65 casting used to cut the 63 tooth gear.

This is the other side of the gear which was face down in the box.

Next time I will count the number of teeth.

Thank you everybody

Noel

Noel,

I have sent you a PM

Eric

Noel,

Some while ago we had another puzzle of this kind, caused in that case by a wheel that had been stamped 54 but was in fact 45 teeth, or was it the other way round, I don't remember the details now.

It caused all kinds of confusion until pictures were posted.

Regards

Brian

.

Noel,

Thank you for sharing that perfect example of 'Make From' ... and the risks associated with it.

By failing to prescribe a suitable '2nd Operation' to obliterate the cast-in number [or by ignoring such an instruction], great confusion was caused.

MichaelG.