Help needed on Boring Bar insert.

[Me.Participant @me1]

I have a large boring bar but for the life of me I can't seem to work out what insert it takes – From the shape I assumed the WNMG type but neither the 06 or 08 fit.

Or is it an internal threading insert and its not a boring bar

Can anyone help please.

[Me.Participant @me1]

Boring bar insert.

[old martParticipant @oldmart]

The shape is right for the WNMG inserts. As they are negative, the seating should dip towards the tip by 7 degrees. If the seating is horizontal, then a variation of the shape which is single sided and with sloping sides, commonly 7 degrees would need some research. Unfortunately, some positive boring bars also dip their tips, so that is not a sure method of telling. It is definitely not a threading tool.

[OldironParticipant @oldiron]

Highly unlikely to be for internal threading. None of my many threading inserts have that shape.

That shape series I believe comes down to WNMA, WNMG, WPGX, WPMT.

If you measure the length of the flat edge that should give you the cutting edge length. 03, 04, 06, 08

IHTH regards

[Tony Pratt 1Participant @tonypratt1]

Not for a threading insert.

Tony

[old martParticipant @oldmart]

I have looked on ebay and there are lots of WCMT type inserts at least up to 08 size.

Can you post another picture of the tool with a WNMG 08 beside it?

If you find that the bar takes some obsolete, obscure inserts, it would be better to look for a bar that takes the inserts that you already have. I bought a 25mm lefthanded boring bar the other day for only £15, not the most popular type, but it takes the common DCMT 11's.

Edited By old mart on 19/05/2021 16:51:48

[DC31kParticipant @dc31k]

As I understand it, inserts are specified by their inscribed circle diameter, so that might be a way of arriving at a likely candidate. Make a peg of some known diameter that fits snugly in the hole for the securing screw. Make another cylinder that fits over this and keep reducing its diameter until it fits the insert pocket. Measure the resulting diameter and compare to standard insert charts.

Does the bar have a manufacturer's part number on it?

[Me.Participant @me1]

Thanks for the replies – i will get a bit more info and some measurements plus a picture of the WNMG insert (the 06 and the 08 ) next to it.

[Clive FosterParticipant @clivefoster55965]

+1 to DC31k asking if there is a makers part or identification number on the side of the holder. Generally holders taking a standard insert will have a standard code as part of the ID number for direct cross reference to the insert.

From your pictures it looks a bit distressed and lightly corroded so time to give it a good clean up. Hopefully a maker and identification number will be revealed from which the correct insert can be cross-referenced.

Be warned there are a lot of specials and single maker types out there. Superficial similarity to a modern, common, standard does not rule out it being an obsolete, single source type that hasn't been made for years. Lots of folk have been caught that way with E-Bay purchases where the couple or three inserts with it are now irreplaceable.

Clive

Edited By Clive Foster on 21/05/2021 16:28:14

[Me.Participant @me1]

It has – Komet JBV 3/810 etched on the side – its slightly worn so can't make it out properly

Its approx 1" square and 300mm long

[DC31kParticipant @dc31k]

I offer this as pure speculation. Anyone who has better knowledge of the facts, please feel free to correct any inaccuracies…

As I understand it, the Komet brand has been swallowed up by Kenametal. A bit of research might find the date when this happened.

Is it possible that instead of a Wxxx insert, it might take a 'faceted triangle' insert? Please look at this eBay listing and assess whether the type of insert shown might fit in the pocket of the one you have:

https://www.ebay.co.uk/itm/164656624125

[John ReeseParticipant @johnreese12848]

As I recall Komet had number of bastard size inserts that were only available from Komet.

[old martParticipant @oldmart]

Now the name Komet comes up, I fear John Reese is probably correct. Some makers like Komet and Ingersol had a habit of making excellent tooling with proprietry inserts which soon were unsurported. I bought a beautiful Garant 6mm solid carbide boring bar cheap on ebay, but ended up having to pay £50 for a box of 10 inserts for it, fortunately still currently available. The good thing about it is that it bores from 7mm and gives a superb finish in steel or aluminium.

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