Machining an Auger? Possible?

[pmurdock]

I would like to make some smaller auger to be used in a salt spreading device that I'm working on. I have a Haas VF-2 with an Auger and looking that that auger it looks like they had some really HEAVY duty machinery to bend some steel square flat into the helical shape. Of course that is way beyond my capabilities in my shop. Can an auger actually be machining out of bar solid on a 4-axis vertical mill (my Haas VF-2 w/ rotary table)? Is this something that is commonly done?

cheers,
Paul

[vlmarshall]

Hmmm... I think you'd need to do it on a mandrel, possibly adding clamps as you went.
Cutting a piece of tube into a big 'spring' sounds like it'd be 'interesting'

[Geof]

I wouldn't say it is commonly done but with a 4th axis it is quite simple.

Do you have any idea of the OD, depth and width of the flutes, inches per turn, total length?

You set it up in your rotary with the end supported in a tailstock and just program the appropriate X and A movement repeating the pass at different Z depths.

EDIT: I am not referring to making an auger the same as the chip auger in your Haas but an auger more like a kingsize wood screw.

[vlmarshall]

I wonder if you could cut it and stretch it into an auger shape afterwards... maybe even do the cutting on a bandsaw instead of a 4th axis.


Now I'm gonna be staring at the chip augers tomorrow at work.

[vlmarshall]

Inches per turn? about 6 inches, in the Haas VF3 and VF6, I'll bet the smaller mill is the same.
It's a big open coil, so you couldn't just stick a tailstock in the other end, or it'd sag and spring all over the place as you cut it.
Start with a heavy-wall tube, and cut a spiral in it like a zero-backlash cutter has, then heat and stretch the thing into shape.

[pmurdock]

Thanks for all the replies.. As I understand it - I will only be able to make an auger with a solid core down the entire length of the auger. I'm probably only looking at about 12" length - OD of maybe 2", flutes can be fairly thick - 1/2" or so, pitch isn't that important.

I guess there's no real trick to it other than programming the Gcode to rotate the bar while cutting in a helical motion. sweet!

cheers!
Paul

[theweldor]

If you do a search you can by auger flighting for ths size shaft and OD that you desire. I build augers quite often. Most any size I have ever made was standard flighting.

[pmurdock]

So you can just buy the flighting and weld it onto a shaft? I didn't realize that.

cheers,
Paul

[Geof]

Are you planning on making it in steel? For a salt spreader?

[pmurdock]

that's probably asking for some serious corrosion issues.. probably should make it out of marine brass or something eh? and forget buying the flighting separate and just machine it as a billet from brass.. super $$$.. any suggestions on a better way?

[Geof]

... any suggestions on a better way?

Use UHMW polyethylene, totally corrosion proof; nothing will stick to it, it is very wear resistant and you can machine from solid at a fantastic feed rate.

[pmurdock]

sounds like someone has been playing with UHMW pe lately.. reading up on it - it appears that it would be good except for perhaps a weakness to UV degradation. Perhaps not that critical though.

Searching up on UHMW PE it appears that it doesn't glue well. Have you had any luck with epoxies or found a good bonding agent for it?

cheers,
Paul