Models for grinding HSS Lathe Tools

[fitterman1]

Starting to make sense now . Seems like all wear takes place on the sides of the shaft journals as the load is concentrated on those points depending on which way you are steering to turn.
Over time as wear increases the cross section of the journal becomes oval shaped.
Therefore if the rudder is pointing at 180 degrees to direction of travel most of your wear will show up at 90 and 270 degrees which will measure less than at 0 and 180 degrees.
I can't see an easy solution to fitting new bushes unless you machine the shaft journals round again as the rudder and shaft will destroy the new bushes in a short time.
I think your friend is up for a new rudder assembly.

 

[Brento]

Any tips on hss grinds for cutting hardened steel bushings about 3/16 in diameter?

 

[Aukai]

I think the start is to find the correct grade of HSS, and to make your DOC deep enough to get under the depth of hardening. Let's see what the gurus say....

 

[fitterman1]

I think you will find they are through hardened at that size

 

[Cavediver]

So, are there still a few of the sample sets floating around? After a couple of months of stalking Facebook Marketplace, I finally scored one of the coveted(?) 1/2hp Craftsman Belt Sanders. I'm working up my material list for the rest and will order materials on Monday. I'm guessing it'll be a month or so before I have the modifications done due to a scheduled vacation, but would love to get busy sharpening as soon as it's complete.

I've also recently purchased a Logan / Wards 10" lathe. It needs a good cleaning and a new belt, but should be good to go around the same time. I'm looking forward to this as I've been using a cheap HF 7x10 with lots of issues...

Attached is the general and very rough plan for the new rest, taken straight from that excellent article by @mikey .

 

[DavidR8]

Calling @Z2V! @Cavediver is looking for a set of HSS tool models...

 

[Brento]

Ive gotten to where i know this hss will cut the bushing. It is a matter of geometry. I havent cut to many things on the Lathe that are hardened

Edit: i am trying to cut this on my little watchmaker’s lathe. I can just go to the south bend instead. Do you think the brazed carbide bits would work good or stick with an insert. It would also help to have a small nose radius.

 

[Brento]

Should i grind a tool as if i am cutting tool steel? This is where i need the Guru help. I have hss cobalt blanks.

 

[ddickey]

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[ttabbal]

Should i grind a tool as if i am cutting tool steel? This is where i need the Guru help. I have hss cobalt blanks.

That's about where I would start with it. A good cobalt should hold up to it, though you will have to watch SFPM. Trying to go too fast will damage the cutter. It's pretty hard to go too slow with HSS. Make sure it's honed well. It really helps.

Inserts should work as well, you will need to get a deeper cut going for most of them though. They can also handle higher speeds, and usually work better with the speed cranked up.

Brazed carbide, you need to shape and hone with diamond tools. As delivered, they always seem to be improperly set up. At least for hobby guys with smaller machines etc.. They might be great on large industrial machines, I wouldn't know.