Tiny Boring Bar

I bought a very tiny indexable boring bar at one of the shows. It had a 3/16" shank and a tiny triangular insert. Once I understood how to set and use it it was very good, but I overdrove it and broke the end off :-/

Has anyone any idea where I could get one?

Thanks

Neil

Has no-one got any ideas...?

Neil

Don't get excited now Neil - I'm often clueless- but surely a man of your experience wouldn't find making a replacement too arduous?

Norman

Neil

Did you take the picture before you broke it, or is the damage not visible?

Sorry I cannot help you find a supplier, I'm presuming you have tried all the usual suspects without success. My smallest one is 8mm Diameter (Iscar, I think) which is positively huge compared with your 5mm one.

What size tips does it take?

Ian P

Perhaps you can look up the show website and if it has a list of exhibitors then check their websites. Or was it a few years ago?

This any good?

Assuming the insert is broken. What is the length of the triangle in mm?

Steve

RDG offer a 6mm dia shank indexable tip boring bar. Simply turn the shank down to 3/16 dia if it is critical. HTH.

Some years ago I made a set of small boring bars and holders from a casting kit Here they hold the small bars very firmly and which helps stop flexing which can cause the breakage of tips, I'm sure they could be adapted to be used with the small indexed tipped bars now available.

Hi Neil,

Have you tried j.b. cutting tools., I bought some small i.e. .110 dia shank and.156 to tool tip

boring bars from them in the past. you would have to make a special holder for them as

they have a near eliptical shaped end on them. Total lenght of bar is just over 1.125

with the working lenght being .625.

Edited By methusala on 06/06/2013 09:16:35

There is no price mentioned so will not be cheap, Niko **LINK**

Thanks everyone. the original bar went ping at the screwhole and the tip flew away and was never seen again, so no way to measure it

It was about 5mm on each side, at a guess. The screw was tiny.

I'm sure it was only about £4 at an MMEX one year.

I have the world's ugliest boring bar made from a bent old HSS drill and it does the same jobs, but less elegantly! Thing is I have a nice QCTP holder with a 3/16" hole in it... so maybe make a new one from HSS.

Neil

Neil, I'v made a bar about that size, for a carbide tip I used a carbide tip from a circular saw blade brazed on the end of a bar made from a bit of steel that was a bit stiffer than a plain mild steel. Same system works OK for normal lathe tools. Ian S C

As you already have a holder for round shank boring tools Neil you may find the following of interest, as may others, as it deals with shaping and sharpening very small boring tools having round shanks.

**LINK**

Will not though be able to comment further as I will be away from the PC for three weeks.

Harold

Most of my small boring is done with home made silver steel boring bars.Can be made very hard. Colin

Can't remember what for, but I did grind a piece of 1/8 HSS for use as a tiny boring bar. Obviously, you can't one a foot long at that cross section

Neil,

I realise this thread is a bit cold now but I had a trade flier through this week offering ISO mini boring bar sets down to 5.5mm dia (with through coolant) but they wanted £178 on offer +vat.

Elsewhere I spotted **LINK**
The lower example on that page is also down to 5.5mm dia. and on other pages they offer inserts too. The price is a bit more reasonable but more than I would spend.

Bob D

Thanks Bob,

A bit beyond my budget, but usefiul as I'd missed Harold's link.

I think I'll experiment with HSS tools, but the tipped one was so easy to use

neil

You could try brazing either a chip off an old tool, or find an old carbide tip circular saw blade onto your old tool, might be worth trying. Ian S C

Neil,

I've made a couple of mini boring bars from old broken taps, centre drill, & picked up a couple of Carbide borers from CNC machines (centre cooling) from somewhere many moons ago..

.. broken tap & centre drill boring bars, the one in the holder is 1/4" carbide, the bottom right is also carbide.. tip dia 0.114". hopefully you can make them out..seem to have forgotton how to set macro on camera.(.it's there somewhere but couldn't find it on menu)?..  so don't dispair you can always make a boring bar out of something.

George

Edited By mechman48 on 16/06/2013 18:11:42