Help To Identify The Needed Insert For This Boring Bar

[janvanruth]

short answer: no, because the rear side of the insert, allbeit the insert is 60 degree, is not parrallel to the spindle

 

[4GSR]

That is better. Thank you.

My though of the pocket was for a TNG (negative rake) insert are out the window. Definitly looks TPG to me. Next would be the size. There is no such thing TPGN122, but there is a TPGN222 inesrt. But remember the "N" in the part number used to stand for "chip breaker" built into the insert. The inesrt in your picture does not have a chip breaker, but that's ok. No biggie. I use them without the chip breaker, too. So the insert number for yours is probably TPG221. The nose radius does not look that big for a TPG222 insert. To verify the insert size, take a dowel pin or the solid end of a 1/4" drill and set it on top of the insert. All three sides of the insert should line up with the diameter of the insert by "eye balling". No precise measurements here. IF the drill is too small try a 3/8" drill for the next available insert size which is TPG321 or TPG322. Let us know what you come up with.

 

[4GSR]

short answer: no, because the rear side of the insert, allbeit the insert is 60 degree, is not parrallel to the spindle

Yeah, I now see the original question, "Can this bar be used for threading" And you are correct, it cannot be used for threading....

 

[janvanruth]

you will be looking for a tpun insert
the second letter indicates a clearance of 11 degree
the third letter can be different as it only indicates tolerance
as for the matter of size, if you measure sizes on the insert that dont make sense, you migtht want to look at metric sizes, the metric size system in inserts is different

 

[Ed ke6bnl]

that tpun sounds good, I did call Viking this mourning about the boring bar and they said they do not make boring bars any longer. they also said they would call me back on the insert BUT still have not herd from them.

 

[4GSR]

Just a little F.Y.I.

TPUN, TPGN, TPG, TPU, and a couple of other designations, all are the basically the same shape and all should fit your holder. You are not limited to just one insert TPUN. Just though you would like this.

Ken

 

[Wreck™Wreck]

Simple triangular insert that is available pretty much everywhere, 1/4 or 3/8 IC, be aware however that if it came from an automotive brake lathe they use inserts not covered by the ISO standards, they are brake lathe industry specific tooling. If a tire shop owner with a brake lathe needs inserts they can't buy them from say, MSC or McMaster-Carr, they have to buy them from a Jobber.

 

[Ed ke6bnl]

looking forward to getting some and trying them 1/4 IC probably and I would need 1/8 thick.

 

[janvanruth]

in order to be sure you will have to take out the insert
are the side where the insert is touching the holder at an angle that matches the clearance angle of the insert?
if it is, you will have to measure the angle on the insert and get the right insert
in t?un the second letter is the angle
a=3
b=5
c=7
p=11
d=20
e=25
f=30

 

[Ed ke6bnl]

I will do that I am very glad there was an insert in the tool. I will check the angle b4 a purchase.