Re: Info for which tooling to buy.
|
Grinding your own cutters will teach you a lot about different clearance and rake angles, chipbreaker grooves, form tools, etc.? I think that over many years I have only bought a box or two of new HSS bits - most have come from flea markets, garage sales and the like.? Nothing wrong with used HSS bits - they may not be the very latest alloys, but should work fine for you.? And someone else has already done the shaping.
In my 6" Atlas, I use two homemade four-way tool blocks, made to hold 3/8" bits at center height.? Takes only a few seconds to rotate the blocks to use a different bit, only a few seconds more to switch the blocks.? So I've got up to eight different cutters ready to go.? Usually no need to perfectly align the cutters perpendicularly to the lathe axis, even with parting tools.? Eyeball is good enough.? More rigid than a quick change tool post.
In my 13" Standard Modern, I use a wedge-type quick change tool post - which is what I got it with.? Carbide insert toolholders more often than HSS, but not always.? Parting tools are HSS.? Many of my carbide insert toolholders are those from very large lathes - 1-1/4" or 1-1/2" square, which I dovetailed to fit the QCTP.
You can sharpen carbide on a bench grinder, using a green silicon carbide wheel.? I don't bother sharpening carbide inserts, but do touch up brazed carbide tools when necessary.? The green wheels do not get carbide razor sharp, though.? Diamond wheels are better.
Carbide tooling is a handy thing to have on occasion, particularly when turning hard steels that would quickly dull HSS.? Although you can run it at a high speed, you don't have to.? Cutting internal threads in pre-hardened 4140, I used carbide threading inserts.? You can bet that I didn't run them at the speed that they would have tolerated.? And you can bet that they gave me a perfect thread profile, and pass a go/no go gauge test..
You'll probably want some carbide, but HSS bits will meet most of your needs.? And don't throw out the lantern tool post if you got one with your lathe - you won't often need it, but there are times when you will.
Hi Lee,
I have a similar set,? I think you'll find that some of those for larger tooling are? a little overkill for these machines. I just about only use 3/8? and 1/4"? HSS bits.? If you use the?
knurling tool as is , chuck material as close to the chuck as you can, and use a center if you can... it puts a lot of load on these machines. I took the wheels off mine and made a scissors action. ? Parting: can increase your heart rate. Really, really, really sharpen the blade, I use the small diamond stick thingies. (think like fingernail file) and lots and lots of cutting oil and with the parting tool sticking out only the amount you need. May the force be with you.
?
HHS bits: Yep, never hurts to learn how to grind them. If you want to practice that I'd try starting with 1/4", it's a little faster and? less material to remove. You do need a grinder and sharp wheel. If you need a grinder, I'd go 8". mrpete22 has lots and lots of how to videos.? blondiehacks is good too. But, while your mastering your grinding skills, you might think about HSS inserts. Skip the carbide. carbide wants speed and rigidity. (my friends told me to get em too... NG).?? HHS inserts you can sharpen, unlike carbide.? Little Machine shop sells them I believe.
?
My $.02
?
Enjoy
?
Kevin B.
|
