8 replies to this topic

[lrosellpardo]

Hi , Anyone know what type of thread is Eq5 worm?? Metric seems the pitch is 2mm

 

[EFT]

All I can tell you is that it is definitely metric.

[TxStars]

It is not really a thread like a bolt has, but a custom pitch angle based on the od of the ring gear / od of the worm.

[Geo.]

Get out the calipers and do the math. Not sure about the metric bit. Vixen was still mixing Japanese WWII standard (Imperial) and metric when they created the Super Polaris.

 

 

 

[lrosellpardo]

Yes, I'v been doing calculations and thread is 1/16 TPI with 11mm diameter rod, I've designed a copy in 3d printed and it works, so I'm going to try to do one in brass with my lathe.

 

 

Edited by lrosellpardo, 29 January 2021 - 02:34 PM.

[EFT]

I have no doubt at all that this worm does not have an imperial thread.  Back when Aeroquest was making replacement worms and ring gears, one of the problems was that their machines were built for cutting imperial threads.  He could get very close to the same pitch with those machines, but not the same so that in most cases the stock worms and ring gears could not be mixed with the new, high precision gears.  The only reason that any mixing could occur was because the thread of the stock worms and ring gears are big a sloppy so that the mesh does not have to be perfect.  You can give it a try and make some new gears and they may work, but it won't be because the thread pitch is correct and you may find a lot of lapping necessary.

[TxStars]

One other thing of note is the thread profile, if you look close you will see that the sides of the (V) are not straight.

These are cut with custom carbide inserts so a standard thread insert will only get you close.

 

Is there a reason you are trying to make a new worm gear ?

 

btw for 10+ years I machined mud motors, which are a worm gear of sorts.  lol

https://en.wikipedia.../wiki/Mud_motor

Edited by TxStars, 29 January 2021 - 06:29 PM.

[luxo II]

At a guess he's dropped his.

[lrosellpardo]

The worm is fine, I just want to do some research, and hoy were right 16Tpi is close but its nota exactly the same.