How Do I Machine Hardened Steel on the Lathe?

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DavidA:
Are you sure that the gear is through hardened and not just case hardened ?

If it is case hardened (and you succeeded in removing the case) then you would really have to re-harden it.

Either way, as mentioned above, it's a grinding job.

Best get a new one.

Dave.

Lew_Merrick_PE:
1) Materials that will cut fully hardened steel tend to be quite brittle, so cutting across you keyways is very likely to shatter a cutter that would otherwise cut such hard steel. (You can take a file to the face of the part and, if it slides across without cutting, this is the position you find yourself in.)

2) Roller chain sprockets are more commonly case hardened to reduce wear than full hardened. Thus, if you manage to cut away the "case," you are likely to be entering yet another world of hurt.

3) The real question is, What changed in the overall engine assembly that moved the sprocket .025 out of alignment? Is there space to have a (hard-drawn stainless steel) shim made to offset the sprocket on the other end of the assembly? Many of the "higher end" mechanics will have a punch set specifically for making such shims. A roll of such shim stock is quite pricey, but somebody who has such material on hand will (usually) let you have it on a "per square inch" basis that makes it a lot less unreasonable.

Manxmodder:
Cubic boron nitride tipped inserts are the way to go if you want to turn the excess material off.

They are available in 2 different grades suitable for interrupted cutting and uninterrupted cutting.

I use these fairly frequently to turn through hardened and case hardened steel components,here is a link to the supplier I purchase mine from: http://www.shop-apt.co.uk/cbn-turning-inserts.html

I usually use the DCMW 11T308 CBN300 CBN type for interrupted cutting as this tip will also perform well on component areas of continuous cutting.(Link to this type of tip here below)
http://www.shop-apt.co.uk/cbn-turning-inserts/dcmw-11t308-cbn300-cbn-turning-insert-for-hardened-steel-45-65-hrc-interrupted-cutting.html

When using these tips the swarf comes off as a bright yellow hot ribbon or yellow hot chips on interrupted areas.

Also when using these tips take care not to bump the tip into anything stationary on the lathe like the chuck as cubic boron nitride is very brittle .

Hope this helps.....OZ.

snub:
Thanks for your replies.

According to the manufacturer the gear is " induction heat treated billet steel".
The gears only come with one backspacing dimension so getting a new one won't help.
The thrust surface on the face of the block has not been altered, so I believe the cause of this problem is the crankshaft. I tried 3 different timing chain sets and the results were all the same. The crank gear is ahead of the cam gear.

I thought about shimming out the camshaft gear but I believe ( correct me if I'm wrong) that this would move the camshaft ahead by .025" which would put the camshaft lobes out of alignment with the lifter bores.

Apparently the misalignment of the gears is a fairly common problem due to manufacturing tolerances so I would have to believe there is a way to cut this gear. After countless hours on the interweb I found little actual data, just lots of speculation.

snub:

--- Quote from: Manxmodder on September 08, 2014, 01:22:13 PM ---

They are available in 2 different grades suitable for interrupted cutting and uninterrupted cutting.

--- End quote ---

I'm not familiar with those cutting terms. Could you enlighten me?

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