# The Cheap Boring Bar Sets



## AR. Hillbilly (Nov 12, 2016)

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.


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## boostin53 (Nov 12, 2016)

You should be able to turn yourself a bushing to fit the boring bars. Then slit it length wise so it squeezes the boring bar when clamped.


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## RJSakowski (Nov 12, 2016)

AR. Hillbilly said:


> 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.



My Grizzly QCTP AXA set took a 3/4" boring bar.  It looks like the Shars set is similar.  If you have an AXA set, the primary diameter should be 3/4" with an adapter sleeve to take it to 5/8".  

Unfortunately, the best way to make a sleeve would be to use a boring bar. Catch 22.  However, If you get a short nipple of schedule 40 black pipe from your local hardware store, it has a nominal *I.D. of .622" and O.D of .840.  If you turn the O.D. the O.D to something like .753" and slit it lengthwise as boostin53 suggests, you should be fairly close to a workable sleeve.   I would machine a short length, say 1/2" for a trial fit and adjust my O.D. for a close slip fit.  then cut the full length sleeve.


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## Groundhog (Nov 12, 2016)

Thick bushing; I recently made a bushing for the same purpose (mount 1/2" boring bars in a 1" holder). The wall thickness is 1/4" so I wasn't sure if it would compress enough because of the thickness. Surprisingly, it works great. I was going to cut 2 other slits part way through if it would not compress enough to hold the boring bars but didn't need to. (I used a reamer to finish the I.D.)


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## Chipper5783 (Nov 12, 2016)

AR  
Pinching the bar, as you did, is not "wrong".  It is not as fast or convenient, but there is nothing really wrong with it.

Make your self a sleeve, as others suggested above.  You can purchase adapter sleeves, but they really are nothing special to make (perfection I'd not required, as long as it holds the tool securely it does not need to be perfectly straight or concentric).  A square holder for that bar is also easy to make, just some square stock, hold it in a regular tool holder, then use the lathe to drill the main hole, swivel the tool post and drill/tap some set screw holes.

Having a square holder is handy for when you need to sharpen that boring bar.


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## Ed ke6bnl (Nov 12, 2016)

Some of my  AXA holders have a V notch in the bottom for holding round material

Sent from my SM-G930V using Tapatalk


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## Jimsehr (Nov 12, 2016)

I have some round carbide bars that are oversized standard sizes and I make boring bars out of them all the time by silver soldering carbide tips to them. They make super boring bars. Then I hold them in holders made for square tools. And I have been doing this for over 50 years.
jimsehr


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## RJSakowski (Nov 12, 2016)

Ed ke6bnl said:


> Some of my  AXA holders have a V notch in the bottom for holding round material
> 
> Sent from my SM-G930V using Tapatalk


I use the V notched tool holder for small boring bars.  I found that the set screws bite into the soft shanks of my bars so I made a cap to fit over the top of the boring bar to keep the boring bar shanks pristine.  I did have to machine some extra clearance in the tool holder though.


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## AR. Hillbilly (Nov 12, 2016)

Thanks to both of you. I'll do just that. I went to the shop and measured the shank. The boring bars are 1/2" and the tool holder is 3/4" with a bushing that's 5/8" I dug through my plumbing box and found a 6" piece of pipe that the 1/2" shank would not quite go in to. I reamed it to 1/2" and started turning the outside to 5/8" to fit in the existing bushing. When I was done the boring bar shank wouldn't go in the pipe so I slit it full lingth and chucked it in the lathe  until the slit was closed and ran the reamer through again. This time when I took it out of the chuck the shank would just slide in. I stuck it in the other bushing and clamped it down. I haven't used it yet to know if it will hold well. Thanks for the idea. I plan to look at more tool holders soon. I get tired of switching out tools in the holders when I could just switch holders with the twist of a lever.


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## The Hermetic Workshop (Nov 12, 2016)

AR. Hillbilly said:


> 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.



Just wanted to point out that the square shank tool holders can hold round tools if you machine a small V groove in the center of the bottom face of the tool clamp. All of my quick change tool holders have this groove from the factory, yours may also. I have never had problems with holding on to round shanks with these style of quick change clamps, and I take some large cuts when roughing out projects from castings.


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## petertha (Nov 12, 2016)

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.


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## Wreck™Wreck (Nov 12, 2016)

AR. Hillbilly said:


> 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.


free upload image


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