Thread: Using a Between-Centres Boring Bar

Originally Posted by nadroj

I've used a vertical slide (milling attachment) to mount a job on, then I had all the positioning control without shimming needed. Only good for what can fit though. Otherwise, a slotted cross slide / milling table could be used. If a cross slide is flat on top but without slots, I guess it could be drilled and tapped for clamping studs. Or maybe the compound slide mount can be adapted to grip the job.

I have a boring bar made by Arrand in UK, with graduated adjustment for the cutting bit.

Jordan

We need to know more Jordan,

Where did you get it, how big, how much etc, etc.?

Bob.

Seeing that made me remember some pictures I picked up on another forum, I am not sure who they where from, but give them full credit.

I don't think it would be hard to make.







And here is another picture of a boring bar micrometer from the same thread.


Dave

Dave,

What do you reckon chomping that much out of the bar will do to the bar's rigidity?

Bob.

I would agree with you on that, I think from memory it was a copy of a commercial made one that was probably made of hardened steel.
If it was made out of a larger bar it would take away that problem, but then it wouldn't do small holes.

Dave

Originally Posted by Anorak Bob

We need to know more Jordan,

Where did you get it, how big, how much etc, etc.?

Bob.

I got it in a job lot of stuff, via a bloke who bought it at auction from a deceased estate. I think the original owner's hobby was buying new tools and never using them, as everything was unused. I think I have most items on the pdf file called, "Arrand Engineering Products" on this site:
http://www.millhillsupplies.co.uk/new_page_7.htm
Size details and prices are to be found there. Apparently Arrand don't do computers so have no website or email. They were in business 6 years ago and hopefully still are. You can Google for their direct phone number and address.

Jordan

Originally Posted by Anorak Bob

Dave,

What do you reckon chomping that much out of the bar will do to the bar's rigidity?

Bob.

Anyone interested enough in me dismantling and measuring up the Arrand bars? I have 2 sizes.

Jordan

What do you think Jordan? Of course!

Thanks,
I would be interested in seeing the insides if you find time, no hurry.

Dave

Jordan,

I just had a quick look at the price of Arrand's boring bars. Even more reason for you to get to work with pen and paper.

Bob.

....or AutoCad.

It's good to see us Aussies think about making one instead of buying. There is another forum I am on where they would just splash the cash and buy one (and anything else posted).
Unlike us guys, they seem to forget what this hobby is about.

Dave

I pulled them apart and took some measurements.
They both have the same brazed carbide cutter. The bigger one has a removable slug.

Jordan

Addit: Note the addition of the flat on the larger bar's insert, since I first posted the drawing.

Thanks for taking the time to do that Jordan, I know how long it takes to go through and do drawings.
You didn't happen to get any pictures of it apart did you?

Dave

Your efforts are appreciated Jordan.

I can see a number of tricky bits.

I have a 1/16" keyway broach but it would not fit in the 1/4" hole to enable cutting the keyways.

The dogs or lugs on the threaded "adjustable bit" are another difficulty along with the incorporation of a cutter in the bit.

How about the idea of an axial slot or keyway in the "bit" and a hardened dowel pin pressed into a cross drilled hole in the bar body and located in the slot to prevent rotation?

Might solve one of the problems.

Bob