Manufacture an helical auger flight from steel plate 4

[15EA]

Hello,

I'm trying to manufacture a steel auger flight these are to be screwed into the ground and act as an anchor, the outside diameter of the flight is 700mm and 20mm thick and are to be welded to a 90mm diameter shaft and the pitch is 125mm.

I’m wondering how to manufacture these auger flights. I know the plate is cut with a profile burner but how do a get it to the helical auger shape?

 

[berkshire]

15EA
I used to make these screw flights for a living, and my advice is: Buy them from somebody already making them.
Try Screw conveyor corp in Hammond Illinois

http://www.screwconveyor.com/productline.htm

The starter flights for their screw lifts are close to the diameter and pitch you require.
If you are determined to make them, a cast or CNC machined die set, formed to the correct helix, and set in an OBI punch press inclined back as far as you can get it, will do the job. Even then you may need to hot form them.
You may however need more than 200 flights to recover the cost of the tooling.
B.E.

 

[Ron]

In its simplest form, cut a 700mm circle. Now cut a 90 mm circle out of the center. You now have an annulus. Cut a straight line through the annular plate from the ID to the OD. Raise one side of the cut 125mm relative to the other and weld along the ID onto the 90mm stem. You now have one flight of your auger.

 

[arunmrao]

berkshire,
thanks for waking me up. 20mm thick auger can be cast with ease. I have been casting augers in different alloys for road pavers,screw conveyors,a continuous annealing furnace retort for cartridge brass,etc. One flight is formed in a sheet metal,by stretch forming manually .This is used as a master for making patterns

Learn the rules,so you know how to break them properly.
Dalai Lama

_____________________________________

 

[berkshire]

arunmrao (Materials)
You know I had not thought of that, I was thinking of the forming die.
But now that you mention it, Malleable cast iron would work pretty well. Also a traditional wooden foundry pattern can be done today on a CNC router for not too much cost.
B.E.

 

[arunmrao]

All grades of wear resistant steels,alloy irons,stainless steels are being cast by me. Malleable iron,one rarely hears of them.Large horizontal lathes are used for turning the wood piece.

Learn the rules,so you know how to break them properly.
Dalai Lama

_____________________________________

 

[15EA]

Sounds like to make a sectional flight its a case of cut out slit ring from a steel plate. Then put the plate in press and push against a die type former and with a bit of trail and error i'm sure this will work. Thanks for you helpful comments.

 

[berkshire]

15EA (Geotechnical)
That's about it, cut your slit ring, put it in the forming die and work the part around. Do not try to do it all at once, or it will distort.Make sure your die set has a short spigot to hold the inside shaft diameter true. Your tonnages will be high because you are going to be stretching 20mm thick material.

You might want to check out arunmrao's casting methods, they may be more cost effective.
B.E.

 

[15EA]

berkshire,

I think your right - what would you you suggest I make the die set of would mild steel do.

In relation to casting I think it would be to expensive.

 

[berkshire]

15EA
I think you will need something a little tougher than mild steel, or you will get distortion in your die set. I am not a tool and Die maker so I cannot advise you there.
B.E.

 

[15EA]

berkshire,

I'm only making 200 number - sure if it gives me trouble its easy enough to repair and if i need better quality i can do that later.

 

[SincoTC]

15EA (Geotechnical),

First let me point out that I have no experience with soil anchors. However, I have seen quite a few auger type lifting screws made by the type of ad hoc methods described in many web articles and basically the same as you are intending to try, and they were very good for lifting loose particulate material, however, despite being made from "easy" light-gauge sheet metal, few approached the true helical form required for easy driving and ultimate resistance to "Pull-out" forces in compacted soil. Maybe the type of subsoil your anchors will encounter will be forgiving of these pitch and form errors.

I know you said that you were looking forward to this project and that you think that a casting (the best bet I think) would be too expensive, but the fabricated route will not be easy and 200 is going to be quite a chore!

BTW, a standard CD makes quick model to get the feel for the geometry, the bore and OD are close to one sixth scale and it's easy to score a radial line and snap it to represent your starting blank. Now you have to pull up on one side of the cut and get it to lie 21mm and parallel to the other side to avoid the "Duckbill" errors illustrated in my previous link above, it's not that easy, bearing in mind that it really should be three times thicker to be to the same scale!

If it were me, I would try and by them from a specialist, but I wish you the best of luck!

 

[unclesyd]

From a long time ago.

You will have to make the inner diameter of your flights slightly larger as it will go eliptical when you pull it for your pitch.

If I recall we always had a left and right segment when using this approach.

Have you looked at the HP requirement for your auger/screw

You might wan't to look at this this company from the banner ad on this page.

http://www.helicalpiersystems.com/?gclid=CJfki8b7l50CFcNB5godNQHcpQRusty