I have a piece of hardened steel

http://www.vxb.com/page/bearings/PROD/20mmLinearMotionSystems/Kit1009

I need to know the poor mans way to cut this down to 40.25 inches.

All suggestions welcome

The serious answer is use an abrasive cutoff disc.

The semi-serious answer is:

Get a length of string two or three feet long.

Tie each end to a little bit of wood to give a grip.

Smear grind paste along the middle eighteen inches of the string.

Loop it over the shaft at the point you want to cut.

Pull it back and forth replenishing the grinding paste as needed.

This will work but I wouldn't want to arm wrestle you after you have finished.

Abrasive cutoff wheel on a cutoff saw.

If you have a large enough lathe, you may be able to muscle your way through the hard case and then cut it off with a saw.

Or, least desirable, the 'gas axe' :D, ie., oxyacetylene cutting torch.

Actually if you have a lathe the string and abrasive is very practical. But make sure you protect the ways on the machine.

You can also semi-automate it; rig up up something to slowly drip the abrasive on, loop the string around ang hang a weight on it, have the spindle running as slowly as possible and go away for a cup of coffee or two.

Actually if you have a lathe the string and abrasive is very practical. But make sure you protect the ways on the machine.

You can also semi-automate it; rig up up something to slowly drip the abrasive on, loop the string around ang hang a weight on it, have the spindle running as slowly as possible and go away for a century or two.


Fixed :D

An 883 grade carbide cutoff tool will do it on the lathe.Maybe about 300 RPM.Otherwise an abrasive cutoff wheel-even on a dremel tool.

Allen

yeah just use a grinder with a quick cut cut off blade on it...might be a bit faster than the string haha, maybe just keep a squirt bottle of water near by and don't let the end get too hot by spraying it every once and awhile.

abrasive is the way to go-it could be put on a cutoff table and easily cut to length-how hard is it, and is it cased or hard all the way thru?

Hi,
This type of shaft is usually just case hardened. Any of the previously mentioned methods will get you past the hard skin. Then a saw or cut off tool should work.
Roger

I have a dremel and a 4" grinder and a hack saw which would you use? or what methods?

Thank you everyone for the support/replies and help!

Hi,
A bit of grinding will get you past the case hardened surface. You can test the hardness with a small file. First try it on the unouched surface. Then, grind down until the file bites into the steel. Now you know how deep to grind around on the diameter.

Once you clean it up laa the way around you can saw the rest.

An abrasive chop saw is a lot faster and easier if you can get a hold of one.

Regards,
Roger

I use an abrasive cutoff wheel from Home Depot in a hand held circular saw. Make sure you got a long sleeve thick shirt, gloves, and safety goggles (lots of sparks flying)

if you have the 4 inch grinder then just get a zip cut disk and cut right through it...really not to tough at all. Don't worry about going through the hardened skin then using a regular saw or lathe or anything this just complicates things...at 20mm thick just zip right through it.

I obtained 3 cutoff discs for the 4" grinder and will be going at it with that. I was so worried when I tried to hacksaw it and didnt scratch the surface :(

BUT!!!! I think I got 'er now! Let ya know soon.

:banana:

chuck it up in a lathe use a low rpm 250-300 use a coated carbide part off tool. the shaft shown is probably case hardened .060 deep so after you get thru the hardened stuff you should be o.k.
rick

Home Depot carries 6" abrasive cutoff wheels made by Norton, .040" thick that fit on a standard 4-1/2" grinder. They cost under $3.00 and you can cut through that shaft a few times with one wheel. Don't force it, let the wheel do the cutting. The nice thing about an electric grinder compared to a 3" air powered cutoff wheel is that it has much more power and the power does not fade with the air pressure. Also you don't get water dripping out the tool after ~5 minutes as with an air unit.

Dave