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Round carbide insert lathe tooling

Jimbojones

Active Member
Anyone have notable experience with these? Wanted to buy a new one but the range of options is overwhelming. Overall goal is to have a finishing cutter that can allow for nominal material removal and leave a smooth finish (I hear the round inserts are the way to go to accomplish this).

I'd prefer shank size of 12mm but can go up to 16mm; insert diameter of 8mm seems useful (plenty of surface area to get multiple uses by rotating insert...but not so big you have problems getting near the end of work) and the larger diameters tend to be thicker e.g. 6mm inserts are usually 2mm wherease 8/10mm are 3mm

Want a right-hand tool so that I can face and turn towards chuck. Seemed like this was enough info but then I started finding so many variations in the tool and the insert prices

e.g. similar tool designations
srscr
srdcr
sracr
srapr

Insert (usually DCMT) are anywhere from $2-10/ea (in a set of 10) and of course different rakes and composition depending on material...

So many combinations....head spun right around over the last few days trying to make a decision.

Is there a good, 1-size-fits-most configuration I can use that will work with both mild steel/alum?
 

Dabbler

ersatz engineer
If you choose a positive rake, it will leave a better finish in Aluminum, but may not be optimal for steel... The best for steel may not leave the best finish in aluminum... there are huge number of factors for surface finish - for instance the triangular inserts I use come in 1/64 and 2/64 radius configurations; the large radius theoretically for finishing....

For a cheap try, you could use this tool:
https://www.banggood.com/SRDCN1616H...-p-1116644.html?rmmds=search&cur_warehouse=CN

I think these inserts might fit:
https://www.banggood.com/10pcs-RPMT...tail-top-buytogether-auto__2&cur_warehouse=CN

I'd be curious about your outcome!
 

Jimbojones

Active Member
For a cheap try, you could use this tool:
https://www.banggood.com/SRDCN1616H...-p-1116644.html?rmmds=search&cur_warehouse=CN

You can't (easily) face with that holder as the cutter is in the middle of the tool...not the side; the SRDCR tool mentioned above would be more versatile for that purpose.

Understanding the differences in cutting steel vs aluminum already, I was more looking for an explanation of the variety of similar holders and personal experience if anyone had already used some of them.
 

PeterT

Ultra Member
Premium Member
I tried a round insert flycutter & I didn't care for it. The theory sounds good: a large radius cutting edge so scallop hill & valley troughs are reduced. And you can perpetually rotate the insert to expose fresh edge. But its kind of the same problem as presenting a big form tool in a lathe. As the cutting edge becomes long, other issues start to arise. Its a bigger chip so needs a very rigid & tight machine to take much more material than a whisker. More friction = more chance of chatter. I'm not saying its all bad but I have a 4 insert APKx 16xx face mill head & that thing will produce a mirror. The difference is I can also do initial stock sizing with teh sam e head & not change over to another tool to finish it off, important for dimensioning. I feel that 2" dia is a good size for my mill because I can take a decent cut & partial overlap like an end mill. Within 4 passes I'm nearing the limit of what my table can accommodate & typical parts I make. So I basically don't use flycutters anymore.
 

Jimbojones

Active Member
Seen some of their stuff before; a bit premium priced for Asia-source but from the photos, looks finer finish. When it comes to tooling with inserts, I'm usually more concerned with the insert quality than the holder; I do have some other Aliepxress-like tooling enroute so will see what it looks like/how it performs when it arrives.
 

PeterT

Ultra Member
Premium Member
On rotating insert tooling, the geometry has to be right or else swapping inserts wont help much. By this I mean geometry related to milled pocket height, angle, depth, screw hole position & any inconsistency between them. This is this is exactly what a guy on other forum is experiencing with a 'Monday Morning' offshore clone of a popular 4-insert APxx face mill. Something is messed up & it cuts like crap despite replacing inserts. Same deal if its not machined concentric or perpendicular to the arbor. Always a bit of a crap shoot with these.
 

Jimbojones

Active Member
Totally agree on the rotating/multi insert tools. Considering the brittleness of inserts I cant image the mess made with inconsistent orientation/positioning...total cost of machining would probably demonstrate no saving at all with a cheap tool. I managed to pick up a few used Sandvik rotating tools so to me that's the value proposition.
 
Just bought some round inserts from carbide.ca They are in Toronto.
Prices were good, check out their surplus section. Delivery was in 1 week.
One of the items was a 0.75 inch x 0.25 inch RNMG 64 for $7.90
Used this round insert to make a set of pipe rollbender dies.
 

Tom Kitta

Ultra Member
I used eBay for all my insert needs and still use them. Premium inserts from big brand names are usually sold for at most $1 if you look hard enough.

Frequently in large lots. Main problem is grading.
 
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