The Cheap Boring Bar Sets

[petertha]

I made 2 smaller inserts that basically plug into either end of the block. The bar is unsupported in the middle but inconsequential. My original plan was to slit saw cut through one side & then partially into the other wall as opposed to 2 separate halves. But I think there must be some magic formula about how much material to leave intact because mine were still very stiff - too stiff to clamp securely. So I ended just halving them. Then I got an idea to bond soft durometer rubber sheet to make a sandwich, 1/16" thick = slitting saw removal kerf. AliExpress to the rescue... maybe Jan-2017. That way the halves will stay intact, but rubber will easily squish when clamped (rubberized collet principle). It was one of those design-as-you-go type projects.

 

[Wreck™Wreck]

I ordered a cheap carbide tipped boring bar set from Shars. I ordered the 5/8' Shank. I needed to use one to bore out a pulley center. I unboxed my AXA boring bar holder and the hole is way too big for the boring bars. I didn't measure the shank yet to see how big they really are.
I had to get this done so I installed one in one of the tool bit holders and used it with great success.
Can I get a different bushing or do I have to buy different boring bars? I don't want to keep using them in a tool holder designed for square tool bits.
This was my first boring project and I needed it done to fix a tool to get a job done. I can't believe how well it worked even though it ws the wrong way to do this. The pulley center had a keyway which made me nervous. I took very light cuts and measured often until it was the right size.
I don't want to create a habit of doing things wrong as a beginner but this did keep 3 men working for the rest of the week.

Not the wrong way at all, many quick change tool blocks have V-grooves just for this purpose, along with holding drill bits.
I run an old CNC lathe with a QCTP nearly every day, 12+ tool blocks 5 of which hold boring bars and internal grooving tools in V-grooves, I do have a round tool block with a 1 1/2" diameter bore only because the other blocks will not fit a round shank of bigger then 1" or so.

For small boring bars less then 1/2" I drill and ream a square piece of material, drill and tap some set screw holes, insert the round shank in it and clamp it in a square tool block, this is nearly a requirement with round tooling 1/4" and less in this situation.

Remember that the only wrong method is one that does not work, the correct method is the one that works.

I made 53 of these very supremely annoying small parts today, .135" reamed bore, .236" OD X .014" step, .079" overall length with a .375" OD from 304, I was only required to make 40 but droped a dozen in the chip tray, the part to part time was a bit under 4 minutes so I just made more to make up for the lost ones, an operation using flood coolant makes them slippery little buggers to handle.
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