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View Full Version : Inserts? SPG or APKT ???



torker
07-18-2008, 12:46 AM
Hey guys.. I was just checking out my two 6" shell mills. They both need a full set of inserts. One uses SPG inserts(7) and the other uses APKT(8) (85*parallelogram) inserts.
Is there an advantage of one over the other?
SPG...cheaper? two more cutting egdes?
APKT? I know nothing about these. Less cutting edges but a lot thicker and maybe an easier cutting profile?
I'm just wondering if it is worth buying so many inserts if the end result is the same.
Would you take one over the other?
Is one more specialized?
BTW.. the SPG is nice on the horizontal for cutting bevels on plates etc.
Thanks!
Russ

lazlo
07-18-2008, 09:47 AM
Russ, the APKT's are modern high-tech rectangular inserts with 2 cutting edges -- they're the new darlings of industry. They've got a very complex cutting geometry, and they cut unbelievably well, especially on low power, low rigidity machines.

You can also get finishing versions of the APKT's where the bottom profile curves into the cutting edge, so it's like a wiper insert plus a cutting insert in one.

The downside: the inserts are friggin' expensive. The most expensive inserts I've seen short of a diamond or CBD insert: ~$15 per insert retail, and $7 per insert on Ebay. I bought a NIB Dolfa 2.5" APKT facemill on Ebay for $3 :D, but it took me awhile to find the inserts for a reasonable price, and I'm afraid to chip the teeth.

SPG's are old-school square inserts. Cheap as dirt on Ebay. Most have a pretty plain cutting geometry. They cut OK, but nothing spectacular like the APKT's.

My personal favorite right now is the Sanvdik RA-290 and RA-245 "Shear Mills". They cut almost as well as the APKT's, but the inserts are around $2 each on Ebay. Here's a thread I posted about it:

Facemill for Bridgeport Part II (http://bbs.homeshopmachinist.net/showthread.php?t=26803)

PaulT
07-18-2008, 01:46 PM
As lazlos stated APKT's are way better than the earlier type inserts, especially on small machines. I get mine from www.carbidedepot.com and the price's aren't too bad.

Paul T.

torker
07-18-2008, 01:57 PM
Thanks guys! Ok.. that explains a few things. Like why they may have sold a newer cutter cheap. The insert price may have forced that.
The APKT sure does look a lot more complicated.

torker
07-18-2008, 02:08 PM
Heh.. I just got an email from my tool guy.
He says this APKT insert I need is VERY common nowadays. It's actually cheaper than his price on SPG's.
Which is odd...I see SPG on sale all the time.

gunbuilder
07-19-2008, 10:51 PM
torker and the group,
I saw an indexable that had APKT inserts in a laid down configuration. At least it looked like a face mill or a shell mill. It was good sized and the first I saw that had APKT inserts in that orientation.

Thanks,
Paul