Any significant subtle differences?

o0norton0o

o0norton0o

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I have a craftsman 6" lathe with a XOA quick change tool post. I had carbide insert tooling that was all 3/8" height based and it fit nicely in the holder. I recently bought a pair of cutters that are 1/2" height based. They work fine so far. I have enough room to lower the cutter so the cutting edge can be centered on my chuck center with a bit of room to spare, so 1/2" tall cutters work with my set up...

My thoughts are that the 1/2" cutter height might be a bit more rigid than a 3/8" cutter, especially if I have to extend the cutter in the holder. Plus it's more rigid in general. Is there any other advantages or disadvantages that I'm not realizing?? It might sound stupid to ask, but I always wonder if I'm seeing the big picture...

Thanks in advance...
 
o0norton0o said:
I have a craftsman 6" lathe with a XOA quick change tool post. I had carbide insert tooling that was all 3/8" height based and it fit nicely in the holder. I recently bought a pair of cutters that are 1/2" height based. They work fine so far. I have enough room to lower the cutter so the cutting edge can be centered on my chuck center with a bit of room to spare, so 1/2" tall cutters work with my set up...

My thoughts are that the 1/2" cutter height might be a bit more rigid than a 3/8" cutter, especially if I have to extend the cutter in the holder. Plus it's more rigid in general. Is there any other advantages or disadvantages that I'm not realizing?? It might sound stupid to ask, but I always wonder if I'm seeing the big picture...

Thanks in advance...
Click to expand...
Half inch is more betta. :grin:
 
o0norton0o said:
I have a craftsman 6" lathe with a XOA quick change tool post. I had carbide insert tooling that was all 3/8" height based and it fit nicely in the holder. I recently bought a pair of cutters that are 1/2" height based. They work fine so far. I have enough room to lower the cutter so the cutting edge can be centered on my chuck center with a bit of room to spare, so 1/2" tall cutters work with my set up...

My thoughts are that the 1/2" cutter height might be a bit more rigid than a 3/8" cutter, especially if I have to extend the cutter in the holder. Plus it's more rigid in general. Is there any other advantages or disadvantages that I'm not realizing?? It might sound stupid to ask, but I always wonder if I'm seeing the big picture...

Thanks in advance...
Click to expand...


You're not really gaining anything between the two, and cutter "Height" is irrelevant.

Theoretically a 1/2 would be more rigid in and of its self, but it is not working by its self, it is part of a system and this comes down to what the weakest link in the system is.

That weak link is your gibs, especially the top slide gibs, and sticking the 3/8" tooling out 2" or so will not cause the cutting forces to , make the tooling "Bend" or deflect before the gibs start to move around.

The larger the lathe and a larger lathes ability to take heavier cuts negates this a bit, but only so much.

On that lathe you would be hard pressed to make even 3/16" tooling bend or deflect.
 
I use a 3/8” hss cutter 90 percent of the time, because an 80 year old blind and deaf machinist named Leftie ground it, and it’s been the most versatile.

Otherwise I use 1/4” cutters because it’s fast to grind. I don’t experience any other difference that matters to me.
 
It's rare that a hobby machinist with a hobby sized lathe will be able to really take advantage of bigger tooling. The lathes are just not built to take the heavier cuts - power and rigidity.

I tend to use 1/4 or 1/8 sq HSS. I've got some larger stuff that I'll grind if I need a lot of tool stick out or a wide profile.

Not trashing small / hobby lathes, it's just physics and design choices.
There are quite a few videos and such on improving the rigidity of smaller lathes.
 
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