# What is that thing !!!    mystery lathe attachment from youtube for cutting helix gears



## joe kozak (Dec 1, 2014)

pictures taken from: 

https://www.youtube.com/watch?v=AhEbvGAmXB4

What is that thing !!!

I saw this chuck/arbor mounted elbow-looking thing making it look awfully easy to cut a small helix gear with a single point involoute cutter.

the gear blank is held on an angled shaft that does not pass through the axis of rotation of the lathe spindle.

Im not sure how adjustable the one in the video is, but I am supposing one that would be adjustible for different
helix angles and diameters could be made,  anyone know where to find the math geometry?

anyone have more info on such a thing ?


----------



## 12bolts (Dec 2, 2014)

It looks like an indexer. Cut 1 tooth, turn and cut the next.
edit Just watched the video, you can see him move to the next tooth at 15 secs. Fair bit of work went into the design of that!

Cheers Phil


----------



## DMS (Dec 2, 2014)

The fixture holds the blank at the proper angle. There is also an attached indexer to move the blank to the next position after each gullet is cut. If you listen closely to the background conversation the machinist is talking about this being a design from somebody else. Don't know what the device is called, but it is quite clever.


----------



## Holescreek (Dec 2, 2014)

What's the orange belt driving the yellow thing do? It looks like the carriage is staying stationary and he's infeeding by hand.


----------



## joe kozak (Dec 2, 2014)

yea, its cool.   i definitely see how it works, but cant quite think-out how to calculate dimentions to make one.   so nobody's ever seen an article on this...?


----------



## vtcnc (Dec 4, 2014)

joe kozak said:


> yea, its cool.   i definitely see how it works, but cant quite think-out how to calculate dimentions to make one.   so nobody's ever seen an article on this...?


Looks like this is the site of the club where this idea came from. http://saskatoonmodelengineers.m.we...28&fw_sig_locale=en-US&fb_sig_network=fw#2310

I'll bet you could contact a member for more info. There appears to be video, but I can't play flash on my tablet.


----------



## chuckorlando (Dec 4, 2014)

Looks to me it's more or less a shaft with a what ever tooth cutter(index plate) he needs. Then a set screw in the front and a finger for the tooth to rest on. Then the housing seems to be made to what ever angle it needs off the shaft that fits the chuck/collet


----------



## chuckorlando (Dec 4, 2014)

Of coarse thats likely a  dumbed down explanation. But in concept, how it looks to me


----------



## vtcnc (Dec 4, 2014)

It appears to be similar in concept to a boring head. Offset the gear blank by indexing to the correct radius from spindle center...then index gear segments on the gear holding spindle.

Here is another photo...would love to get a copy of this article.

http://www.pbase.com/image/102836065


----------



## H.K.Barrows (Dec 4, 2014)

Good morning to all This was published I 2008 in Model Engine Builder issue #16 March/April. The author is Alan Suttie , There are complete drawings also with pictures. Contact modelenginebuilder.com. If you have not seen their publication in my mind as a model builder it's a must. Regards Red


----------



## 12bolts (Dec 5, 2014)

chuckorlando said:


> Of coarse thats likely a  dumbed down explanation.


Dumbed down explanations work for me............

Cheers Phil


----------

