Surface Finish

[bug_hunter]

Hey All,

Should i be able to achieve a smooth to the touch finish with a 1942 South Bend 9? I'm using HSS tools. I started out turning a rusty piece of 2-inch A-36. All the rust is gone, and getting close to my final desired diameter 1.500. But no matter what I change (spindle speed, feed speed, depth of cut, tool end, oil), I cannot achieve that smooth finish. I still feel slight discrepancies when I run my finger across it. I've attached a photo, but I do not believe you can see much in it. My best finish comes from a high spindle speed (690), shallow cut (.002), round tool tip (~1/8"), with oil.

Is it my technique, the lathe, the material, or the phase of the moon? Let me know if there are any questions i can answer that may help in formulating an answer.

Thanks!

 

[Jim F]

Try a vertical shear bit.

 

[bug_hunter]

Try a vertical shear bit.

From the photos I have found, unless I am mistaken, and I may very well be, does the bit cut, or shear from the bottom as opposed to the normal top cutting bit?

 

[Jim F]

It shears from the side, works great for low power machines and hard to finish metals.
As much as I dislike his videos, MrPete has a few on making and using one.

 

[woodchucker]

not enough info:
pics of the tool
was this using a feed, or done by hand?
What was the feed?

First, I notice that when I cut light cuts the finish look eh.. but when I do the right size cut I get a nice finish.... too much and eh...

I don't use a shear tool. I find it dulls pretty quickly in steel. For AL, it's nice .

 

[benmychree]

A36 is not known as a free cutting steel that will finish nicely, it will take filing and abrasives to make a nice smooth finish.

 

[woodchucker]

It shears from the side, works great for low power machines and hard to finish metals.
As much as I dislike his videos, MrPete has a few on making and using one.

why do you dislike his videos? Just curious.

 

[Jim F]

why do you dislike his videos? Just curious.

Too much rambling about stuff that does not pertain to the subject at hand.

 

[bug_hunter]

I had very little expectation, but it works. Does not make chips, as much it makes little steel feathers. The finish is a lot smoother, but not like glass. Maybe one more pass and we'll call it good.

Thanks for the new trick.

I actually did watch one of Mr>Pete's videos on the tool. I like him. He may ramble, but at least you can hear him and understand what he is saying.

 

[C-Bag]

Having been partially raised by my grandfather I’m kinda partial to knowledgeable rambly old guys. I don’t always agree with their politics, but I appreciate their knowledge. Mr Pete is a treasure to me.