Indexable fly cutter

Hi folks. this is somthing that someone has no doubt done allready but here goes anyway. Fed up with trying to grind a nice slight radius on my HSS fly cutters, i thought i would give this a try. I bought a 6mm profile lathe tool and used it in place of the HSS tool, and ,suprise,suprise it worked great. I was taking 0.5mm cuts at 600rpm no problem ( on brass, yet to try on steel ) Moderate feed rate by hand (no power Xfeed ),and a very quick rub on a sheet of 380 grit paper removed all milling marks.

Cheers Derek

Derek,

That looks very promising !!

Any idea how many "fresh edges" you can expect to get from the circular insert ?

MichaelG.

Excellent idea.

Neil

Thank you Neil, And Michael. I have no idea how many fresh edges,but i would think quite a few, if you were only taking small cuts. I have been using a 12mm shank tool on the lathe, that takes the same tips for a few years now,and i still have 8 tips left from a box of ten. 90% of stuff i do is brass or ally so not too hard on tools. When milling the pyramids, i faced up around 20 square inches of brass with no discernable wear on the tip, when checked with a X10 loupe.

Cheers Derek

Derek, is the profile tool insert HSS or carbide? If it's carbide, do you have any problems with the interrupted cut?

Sid

There is interrupted cut and interrupted cut, it all depend on how interrupted, speed, material, tip type etc.

I have never found any problem with discontinuous cutting using indexable carbide tips. Today I turned 20mm square stainless to 12mm diameter and no drama was involved. I could imagine that doing the same with a larger size on really tough steel might be tougher but its done all the time in industry but probably done with the right tip.

After setting up the material today in the 4 jaw, I took light cuts and got peppered with tiny fragments of stainless, so I used plan B and took all but a finishing cut in one (slow) pass. In reality it was no longer an interrupted cut, just a cut of varying width.

Ian

Sid, I think Ian has answered your question better than i could. As i got toward the tip of the pyramid, there was a lot more interrupt than cut, and after cutting 8 of those faces , the tip was still fine.

Cheers Derek. Ian please check your PM's

Thanks Ian and Derek. I have one of those profile tools sitting around doing nothing much - I'll give this a try.

I can't say if these types of fly cutters would be avalible in the U.K. But they are in North America. Their built by "New Generation". They do take a bit larger round industrial carbide replaceable tip, but that can be a good thing since various grades and coatings are avalible in those sizes. Unless you make a large error and badly chip or totally destroy the tip, their really cost effective. They might be a bit too large and heavy to be used in something lighter than a Bridgeport type mill since they can be adjusted up to a 6" diameter.

Pete