Boring bar holder ineffective

[IHinIN]

I have that same style of boring bar holder. It only came with a 3/4”x5/8” sleeve. I made a 3/4”x1/2” sleeve and it holds my 1/2” bars fine.

 

[Makintrax73]

Can you turn a single bushing and slit it with a slitting saw?

This is what I did. If you have a 1/2" reamer its a super easy job. I made mine from 6061 which I dont suggest you do since it tended to be sticky adjusting the bar.

Order up a piece of 1/2 drill rod and a piece of 1/4 hss and you have the makings of a fun day in the shop making your own tool to go in the holder.

Or just stick it in a regular v slotted tool holder but where's the fun in doing it the easy way?

 

[WobblyHand]

Speaking of the hard way, why not make your own custom tool holder? Then you can slit the holder, like the BXA-4D.

But. yes, the easier way is to make a custom bushing for each boring bar you have. I did that one day, it was well worth the effort. I do prefer the tool holders that have the slit over the pinch points. I have perhaps an irrational fear that it would crack a carbide boring bar, so I use the 4D type holder and bushings for them. For the steel bars, I use whatever is handy.

 

[Chipper5783]

Mine also came with only one sleeve - it holds the smaller bar no problem. Per comments by others, I’ve made sleeves for other size boring bars (but not slit - just a reamed hole that fits the boring bar well and a couple set screws). Works great.

 

[OTmachine]

And …., if you look at the design of the boring bar holder, you will see that the split in the bushing needs to be at the 12 o’clock position, as the clamping action is applied at the 9 o’clock position.

 

[woodchucker]

I have an AXA boring bar holder that uses two bushings to hold a 1/2" boring bar. But the bar almost spins like a top... the grip is not strong at all. I have disassembled to check for defects or issues. Perhaps the issue is the user. Any suggestions?
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DanK

I made a single sleeve. My 3/4 block has a sleeve for 5/8 and I needed a smaller one. I quickly roughed out a piece of steel and slit it. I custom bored the hole for the bar.. no problem, the slit on mine should be at 12 or 6 oclock, since the screws put tension across. if you have your slit like you do, it won't close the sleeve.

 

[woodchucker]

Line up the slits on both sleeves on the side with the bolts so they pinch both sides of the slit.

that's not how they work. there are half moon cut outs in the bolts, so you want the slit at 12 or 6 oclock

 

[woodchucker]

Imo it’s a junk design meant to make you think you’re getting more than you bargained for.

The only issue I have with putting your boring bar right in the tool holder is it can mark up your shank if the set screws have anything other than a square flat dog point.

This type of holder does not mark it up. It's pretty much the same design as the quill lock on a bridgeport.

 

[woodchucker]

That holder is a good holder. The way it clamps does not deform the bar, it also supports the bar 100% in the sleeve so no issues there. Any deflection is at the end of the holder. The statements that they are junk are based on what? Throw up some info to prove it. Because from an engineering point of view the only drawback is that the boring bar is slightly farther away from the tool post. Other than that, it has no inherent weakness. If you think it does, make a case.

 

[Batmanacw]

that's not how they work. there are half moon cut outs in the bolts, so you want the slit at 12 or 6 oclock

The half moons pull together from top and bottom. Lining up the split between them will pull the slits closed and grip the bar.