Slitting Saw , Enlarging The Hole ?

[JimDawson]

It is completely possible to make new arbors on your mill. You have a RT, and a boring head. The boring head will cut on the outside of a part just fine, just turn the tool bit around. Instant lathe, sort of.

As far as a spindle grinder, this is what I did http://www.hobby-machinist.com/threads/50-000-rpm-mill-spindle.23186/

Here is another one that I found on the net

 

[Subwayrocket]

Yes , I used the boring bar on the outside of a brass counterweigh I made for my fly cutter . Yes it kinda works ...cant push the bar too much before deflection though . That is a pretty neat setup youve got there !

 

[mikey]

Yes , I hear you on all that . And yes they are cheap . I can afford a few ...it's more just part of the hobby for me...see if i can do it. Maybe learn something in the process . I have some slitting saws already so this is not out of necessity. And yeah , no lathe . Wish I had one ...maybe next year , tax time . There's only so many changes that go "un-noticed out here ...dont know how the misses puts up with me...she's an Angel !

Oh, believe me, I get the "see if I can do it" part! I happen to have an Angel here, too; not sure why she puts up with me but I'm glad she does.

 

[rick9345]

If one thinks real hard on this problem, the rotary table does not have to be mounted on the mill nor does the grinder. Ingenuity will solve. The important is to have the slitting saw centered on RT

 

[JimDawson]

If one thinks real hard on this problem, the rotary table does not have to be mounted on the mill nor does the grinder. Ingenuity will solve. The important is to have the slitting saw centered on RT

That's what I like, outside the box thinking. Great observation!

 

[rgray]

When I wanted an arbor that was true for a slitting saw I put a piece of 1144 in a collet in the spindle of the mill and clamped a tool bit in the mill vise and cut the shaft down to size for the slitting saw hole, vertical lathe style. Drill and thread the end and build a cap to hold the saw on(do that part first).
It's then perfectly concentric till removed from the spindle. Didn't cut much smoother. I hate slitting saws, but they are a necessity sometimes.

 

[george wilson]

You will likely find that trying to grind the hole larger will take forever,and will eat up a LOAD of grinding wheels.

You need to get a lathe!! You are in a formerly big manufacturing state. Should be possible to find a decent used one up there. If you had a lathe,you could make arbors for those cut off saws. That would be a lot easier than trying to grind out the holes. I would use carbide to cut the holes larger myself. But,not end mills. A simple fly cutter that I could re grind when it breaks would save on expensive carbide end mills.