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Any smal lathe owners using indexable tooling ?
- Thread starter oldgascar
- Start date
These are your best bet. Since you're in the 12" range, you could possibly go with 1/2" shank depending on your toolpost holder and overall rigidity of the machine. You'll benefit from a QCTP in either AXA or BXA size. Cutting w/carbide requires 2 to 2-1/2 times the SFM compared to HSS and the machine needs to be rigid enough to handle the higher pressures. Some years ago, I switched to carbide and much prefer it due to the consistency. Anyhow, if you order this set, get additional inserts. They're also commonly available on eBay from "Carbide Now" in packs of 10. The bits all have positive relief and worked perfectly on my old Atlas TH-42. BTW: Tools4Cheap.net also sells these kits at a slightly better price and I belief Jeff also sells on eBay.
http://www.shars.com/products/view/2763/38quot_Indexable_Carbide_Turning_Tool_Set
I have these tools in 3/8 and 1/2" and they do 80% of my work. I use the 3/8 with AXA more than the 1/2" and my lathe is a light industrial 12x36 Precision Matthews 1100lb machine.
For really rusty stuff, I use the cheapo Harbor Freight RH & LH bits to cut past the scale.
http://www.harborfreight.com/pack-of-10-ar-8-rh-carbide-tipped-lathe-cutting-bits-2788.html
Ray
http://www.shars.com/products/view/2763/38quot_Indexable_Carbide_Turning_Tool_Set
I have these tools in 3/8 and 1/2" and they do 80% of my work. I use the 3/8 with AXA more than the 1/2" and my lathe is a light industrial 12x36 Precision Matthews 1100lb machine.
For really rusty stuff, I use the cheapo Harbor Freight RH & LH bits to cut past the scale.
http://www.harborfreight.com/pack-of-10-ar-8-rh-carbide-tipped-lathe-cutting-bits-2788.html
Ray
I 2nd the cheap set from shars or ebay. I have a couple sets from different sources and as best I can tell there isn't a nickles difference between them.
In my experience the inserts that come with them are miserable. They cut but nothing like a proper insert for the job at hand.
Steve
In my experience the inserts that come with them are miserable. They cut but nothing like a proper insert for the job at hand.
Steve
I use some of the cheap TCMT 21.52 (and some 21.51). They cut and leave a decent finish on most things. If I want a nice finish, I go with HSS. For now, I just have the 5 piece set that have them at different angles. I will be making some new holders for my QCTP that hold them directly. Also a boring bar to hold one.
I am sure that the better inserts would give longer life and better finishes in a production setting. Not sure that it makes that much difference for home use. I tend to take light cuts and low RPM on my little lathe and don't have the power to really hog stuff off anyway. I really don't care if it takes lots of passes to reduce stock.
I am sure that the better inserts would give longer life and better finishes in a production setting. Not sure that it makes that much difference for home use. I tend to take light cuts and low RPM on my little lathe and don't have the power to really hog stuff off anyway. I really don't care if it takes lots of passes to reduce stock.
Yeah Steve, now that I think about it, the original inserts didn't last long as I recall. The holders are good though. The 1/2 and 3/8" holders use the same inserts and all of them are available in 1.5 and 2.5 (or is it 2.0? -can't remember) radius. I use them both and have my 3/8 setup for 1.5 and the 1/2" setup with the 2 or 2.5. I've got them in C2 and C7 carbide. Packs of 10 cost something like 20 bucks and last a long time.
David,
Not sure about what size/power lathe you have but, you really can get a HSS finish using carbide. Spin at about 3 to 3.5 x the HSS SFM and take passes of at least 6-7 thou (depending on tip radius). When the stringers are coming off blue, you get a perfect "gloss" finish with carbide. Kicking-up the RPMs beyond the usual 2 to 2.5 x is the secret sauce (provided your lathe is stable and vibration free at those higher R's)... Give it a try.
Don't get me wrong, HSS is great and I use it when and as needed but, every darn time you touch-up the bit, you have to re-center and that problem doesn't happen with carbide.
Ray
Not sure about what size/power lathe you have but, you really can get a HSS finish using carbide. Spin at about 3 to 3.5 x the HSS SFM and take passes of at least 6-7 thou (depending on tip radius). When the stringers are coming off blue, you get a perfect "gloss" finish with carbide. Kicking-up the RPMs beyond the usual 2 to 2.5 x is the secret sauce (provided your lathe is stable and vibration free at those higher R's)... Give it a try.
Don't get me wrong, HSS is great and I use it when and as needed but, every darn time you touch-up the bit, you have to re-center and that problem doesn't happen with carbide.
Ray
I second that set of Shars 1/2" and the secret is they will use the Warner HSS inserts http://lmscnc.com/3696. This one of those things that Shars does make well. I do use some carbide for harder materials or cast iron but don't like the speeds needed to get that mirror finish the same as HSS on 1018 ect. Also these are very easy to sharpen without even removing the tool from the lathe. Just take the insert out of the tool. I use a small knife honing stone and a drop of oil turn the insert upside down and move it in a circular motion on the stone with your finger. In about a minute or less it will be razor sharp again. No need to sharpen the sides. No need to change anything for set up as there are no angle changes.
The major difference between inserts is the good ones are designed for the material and job ie stainless roughing, alloy finishing etc. It's a matter of the inserts geometry. It's not really a 1 size fits all solution.
For stuff that don't matter too much we all tend to find a "GP" insert that works OK on most material and processes and even excellent results on more than a few. I ran across a good deal on some. I've got ~4 different varieties and I can usually get decent results.
My big lathe is a 1 1/2 HP 12x36 so I am not running much power. Like Ray says carbide likes heavy cuts. I'm usually cutting .03r at .01"/rpm to get an idea how the job is going to go modify it to get good finish and safe chips. It is usually best to not do a final skim cut to size but just make the last cut much as the previous but right on size with inserts. Indigo blue 6s to the end.
Steve
For stuff that don't matter too much we all tend to find a "GP" insert that works OK on most material and processes and even excellent results on more than a few. I ran across a good deal on some. I've got ~4 different varieties and I can usually get decent results.
My big lathe is a 1 1/2 HP 12x36 so I am not running much power. Like Ray says carbide likes heavy cuts. I'm usually cutting .03r at .01"/rpm to get an idea how the job is going to go modify it to get good finish and safe chips. It is usually best to not do a final skim cut to size but just make the last cut much as the previous but right on size with inserts. Indigo blue 6s to the end.
Steve
Good words here from Steve about safe chips. Hope you don't mind Steve but I'll give an explanation about what "6s" are for those who don't know. 6-7 thou is nothing and most cuts are in the 15-30 range. With lighter cuts, the chip breaker groove sometimes doesn't do it's job and you get stringers (long strings of spring swarf). Even with heavier cuts, if the bit is not positioned just right, you could end up with a stringer coming out at you faster than you can get away because the RPMs are 2-3 times faster than HSS. Even little skinny stringers can cut you or pull your finger in and the heavier ones have been known to sever arteries, cut tendons etc. Never touch any kind of swarf from a running machine -even the skinny stringers. Reposition the bit so you get pig-tails (2-3 loops about 1/4" long) or little pieces shaped like a "6". -And keep e'm off the top of your hand because the the shearing action heats them to a (very colorful) blue. Which makes nice pigtail and 6-shaped red blisters.
See, that's the problem. My little 350W motor and steel, 6-7 thou can be my hogging cut.
I usually stay with 12L14 and 1144 alloys. They behave better. "A man has just gotta know his limitations...."