I bought a set of flycutters on ebay, and I'm pretty sure these are the ones for which a company posted a special here a year or two ago. Thought I'd saved that post and/or URL, but cannot fine either. Does anyone recognize these flycutters and have the URL? Need to buy some inserts. Here's the auction link:
Jon, Can't say I recognize them...but they are radicaly differentthan any other fly cutter I've ever seen. I'll ask around & see if I can help you locate the inserts. A couple of ??? for you though (I'm interested here):
1.) Do the inserts glue or braze on? I didn't see anyplace for a screw.
2.) Being round...is the cutting edge of the inserts 360 degree rotatable...for a cutting edge around the entire surface?
3.) Are these things a better roughing cutter than they are for finish work?
Rotary Technologies: The URL for the cutter inserts is:
There is a single screw in the center.
Pretty close. IIRC, there are 12 rotary positions in which they can be mounted, and then you can flip them over for another twelve surfaces.
Actually -- checking the web site, it depends on the depth of cut.
Depth of cut : inch .03 .12 .25 mm .08 3.2 6.3 indexes/insert: 24 12 8
So -- the deeper you cut, the more of the edge you wear, and thus the more positions it needs to be rotated through before it reaches the next clean cutting edge for the full depth of cut.
They can produce a beautiful finish with a sufficiently rigid machine. But, as you can see from the table from their web page above, they can be used for up to a 1/4" depth of cut, if roughing is your game.
But -- before you go overboard about these, look at the prices for the inserts, and the minimum orders of a box at a time. The 1/2" size can range from $196.70 (for a box of ten in one grade) down to $53.11 (three per box in another grade). So -- it is around $17.70 -- $19.67 per insert.
If it works for you, and you're getting paid for the work, it can be worth it.
These look as though they are a bit tapered to me, although my eyes are a bit dodgy. I remember reading an article in an old edition of Model Engineering Workshop, where a contributor described a simple way of making these from tool steel by tapering and parting off several from the correct size rod. It looked effective. Might work for you.
Welll Ill be damned. I dont know who the manufacture is..but Ill can tell you who did the grinding and finish work. It was All Diameter Grinding in Orange, California.
Ive been giving these things away for years, sans the inserts as I got several hundred pounds of the rejects...out of round by .0005 etc.
Ask for Marv or Jeff
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
Yes, one of the reasons I wanted them. Loosen the screw, rotate insert a bit, carry on.
Only did a test cut last night, picking the one with the best insert. Looking at the geometry, I'm not sure just how much roughing they will take, but they sure give a nice finish. For a less than new insert, I sure got a dang decent finish.
My interest wasn't for roughing however, I like the near full circle of the body. These are very well balanced. Ran the big one up to 3400 rpm and no noticeable vibration at all. Sure wouldn't try that with the type that use brazed lathe bits!
The single insert almost insures a great finish. With multiple insert cutters, if one insert sits even a tenth lower than the others, you can see it in the finish.
Which works out to less than a buck per index. But I lucked out, turns out I have the older bodies that don't have the hex star. Since I bought these strictly for light facing operations at shallow depths of cut, I can index the inserts only as far as needed to bring a fresh edge into play, potentially getting even more "indexes". Just got off the phone with Rotary Tech and they confirmed the current style inserts will work fine with my holders.
I'd guess one box of inserts will probably last me many years, though it sure is a steep initial purchase.
Most of my flycutters are el cheapo crap I bought 15 years ago. None of the larger ones can run at that rpm without vibration from being out of balance. Always intended to do something about that, and just did, by replacing them!