How do I use (adapt) a quick change boring bar holder?

[zippyslug31]

I have a quick change boring bar holder basically like this:

I also have a set of 4 boring bars, each with varying bar diameters so what's the best practice on using these together? Do I machine myself a set of collars with the OD that will slip into the holder and ID made to fit each bar? I'm thinking I'd just hold the bar in place with a grub screw.

I have seen some boring bar sets where each in the set has the same diameter shank, so I probably should have bought that set instead, but here I am.

Just looking for a way to use these together... maybe I'm missing some pre-existing doo-dad that I need to buy?
Thanks for any help.

 

[D.sebens]

As it is that holder will hold 1/2 and 3/8 shank bars. What is your diameters?

 

[zippyslug31]

...will hold 1/2 and 3/8 shank...

No, mine looks like it's limited to hold 1/2" (I believe) only. The slip collar inside has a very limited range of closure and appears to be built for only a given size of shank.


The bar set that I got was just a cheap-o fleabay purchase.



Not sure the exact size yet, but they seem to work fine for lighter boring operations, but I had to mount them in a standard QC holder but was looking use the bar holder that I own. The "adapter" idea was what I came up with but it occurred to me that maybe there's already a solution to the different sizes.
But... I'm starting to think I just have two different things and should have bought something different?

 

[D.sebens]

It looks like mine but I guess it could be different sizes. The slip collar is an adapter. You take the collar out and use it without for larger bars.

 

[Just for fun]

Mine that looks like that holds either a 3/4" with the adapter or 1" without. For smaller bars I just use my standard tool holders. I have a really small boring bar maybe 1/4" diameter, I have not figured out the correct way to hold it yet.

 

[Shotgun]

I'm in the same situation. I was going to make collets adapter for the smaller bars, with a set of slits extending in from both sides. But I like the idea of a grub screw or two better. Then I can turn some stock all to the same diameter, drill the hole to a tight fit. . not even bothering to ream it. . . then a single grub screw. Every bar would have it's own adapter, making swaps easy.

 

[D.sebens]

As an alternative, one of the qc tool holders has a v milled in it for holding round objects. You could use that.

 

[zippyslug31]

I had thought that this tool holder required the slip collar, but now I understand - can be used either way and I'm mistaken thinking it could only be used for a certain size. The more you know!

I do have another holder with the V grove, but I'd really like to make use of this bar holder.

I think I'm going to give making an adapter for each bar a try. Even if it doesn't work out, it's still good practice for me to try and nail dimensions, both ID and OD, all for the different bar's diameters.

 

[zippyslug31]

Every bar would have it's own adapter, making swaps easy.

Yep, this was my thinking. The only real downside that I was thinking is that when you swap out the bars they'd have to be oriented correctly again to get the given bar's cutting edge and relief rotated correctly. Not a huge deal tho.

 

[T Bredehoft]

when you swap out the bars they'd have to be oriented correctly

Just a thought, make each adaptor for one bar, put a tiny set screw in the adaptor so the bar and adaptor maintain position, then put a notch in each holder in the same place (on the back end?) so that when it is inserted in the quick change holder they will all orient in the same position.