Metric threads on a Powermatic?

[RonRock]

I'm in need of doing some metric threads on my Logan 1937.

Not enough to justify the price of the ebay printed ones. But I do have a 3D printer. I searched and could not find the files needed to print my own. Anybody here figure this out and care to share?

 

[brino]

I'm in need of doing some metric threads on my Logan 1937. Not enough to justify the price of the ebay printed ones. But I do have a 3D printer. I searched and could not find the files needed to print my own. Anybody here figure this out and care to share?

Hi @RonRock,

See here:
https://www.hobby-machinist.com/threads/gears-for-my-oldtimer-lathe.82245/post-718054

It can be done for free!
Feel free to PM* me if you need help.

-brino

*PM = Private Message. Just hover your mouse cursor over my user name and then hit "Start conversation" on the pop-up.

 

[RonRock]

So I broke down and bought a pair of 37/47 gears. I have read many many threads on how to do metric threads on a Logan. For the life of me I just can't get it sorted how to set up my lathe for metric.

Many different thoughts and suggestions, just not one that I can wrap my head around. So I will ask if someone can point me in the right direction.

Here's what I have,

 

[RonRock]

Those are a little big. Sorry I thought that the forum would format.

I should have added that I have a Logan 1937 with quick change gearbox.

1.5 mm pitch is what I'm after this time around.

The 37/47 gears fit the shaft where the 36 tooth Stud Gear is. The shaft that holds the 72/64 is smaller. I would have to make a bushing for the 37/47. Can be done easy enough if needed.

The 72 tooth "Safety Gear" drives the QCGbox. Part of what is throwing me off is that I am seeing that that 72 tooth is often shown as a 60 tooth.

 

[ErichKeane]

As you've got it setup, ONLY the final 72 tooth and the 36 tooth gear matters. The 72/64 pair are doing nothing. SO, you've got a 2 to 1 ratio from spindle to gearbox.

What you need to do is put the 37 and 47 gear on the same axle (where the 72/64 is!). Drive the 47 tooth gear with the 36, and have the 37 be the output of the conversion (going to the 72 tooth gear).

As far as selecting a metric value, that would depend on the gear ratio in your gearbox.

 

[RonRock]

Thank You ErichKeane.

Looks like I need to make a axle that will hold the 37/47 as well as "pin" them together.

Very helpful.

 

[ErichKeane]

Thank You ErichKeane.

Looks like I need to make a axle that will hold the 37/47 as well as "pin" them together.

Very helpful.

You SHOULD be able to replace your 72/64 pack there, there should be a keyway on the shaft that you can use to put those together.

 

[RonRock]

My 72/64 had a keyed bushing that holds them together.

I pressed it out. It might fit the 37/47 but would be a very tight press fit. I think that I'll be best off to either buy or make one. Then I can put them together and leave them. Not have to worry about fouling the fit going in and out with the bushing.

Is the bushing a piece I can buy?

Mine measures .437 id. .625 od.

Sent from my SM-G930V using Tapatalk

 

[ErichKeane]

Looks like they are a bit expensive to buy, its probably easier to just turn one

 

[ErichKeane]

(Whoops, double post!)

As it likely wasn't your fault, I'll leave you with credit for the post. This is at least the third maybe fourth instance of this that I have seen since the server upgrade. Most of the time the "Save" action is quick. But sometimes it takes several seconds and it appears also that if you click Save again while the fluctuating gray boxes are appearing under the right end of the main toolbar at top of screen, sometimes the Save command gets saved in a que somewhere and saves the same post twice.

WA5CAB/Robert D.