lathe tooling

[keithh999]

I have a couple questions on lathe tooling....is it more economical (long term) to purchase carbide insert style bits or try and stick with HSS tooling that can be ground inhouse?? My 9" southbend rocker holder has a 1/4-5/16" capacity for tooling...can this be upgraded to a larger size holder (since i have tons of larger sized tooling..up to 1/2") If the consensus is to stick with HSS tooling what kind of grinder stone should i get and where and at what RPM should they be ground at??? If the consensus goes to carbide tooling what should i get?...MSC has thousands of numbers that mean about zero to me and have no way of deciphering the gobbledygook in the catalog and i dont really know any machinists to ask...as i stated above i am limited to 5/16" tooling and trying to figure out the carbides and holders is making me gaga...LOL
any help with these questions would be greatly appreciated!!!!
thanks in advance guys

[trying-it]

For now, see if this link opens from the mscdirect.com site; it shows a totally different approach to tool holding in a lathe (your size lathe included).

MSC Item Detail

[HWooldridge]

HSS is fine for most home use in a non-production environment and common materials. I grind bits on a belt grinder with 120g belt and they work fine. IMHO, a better investment for any lathe is to buy an Aloris equivalent quick-change post and holders. The old rocker style is OK on some work so don't throw it away, but most of the quick change units are robust and will really help your productivity.

[the_sandy_creek_forge]

Hey Keith,
Let me frame this with a disclaimer *I am in no way a machinist. I just happen to utilize a small lathe and a metal shaper to make jigs, dies, etc. for my blacksmithing work*

I started out on the lathe with some of the cheapo brazed carbide bits from HF and a set of the cheap indexable ones from grizzly (all 3/8") Then when I got my shaper, I discovered HSS bits. I personally prefer the HSS for everything that I do now. I can get a pretty decent finish, but my tool grinding skills do need some work. One of these days I'm gonna meet with the local high-school shop teacher to get some pointers, just haven't had the time yet. Right now I grind my bits on a regular old 6 inch bench grinder and then touch them up with a medium grit pocket stone to make everything nice and smooth. Making an adjustable work-rest and setting up a dedicated grinder for grinding tooling is also on my list. I also like HSS because, If you keep an eye on ebay, you can sometimes get a large lot of gently used tooling for a decent price.
-Aaron @ the SCF

[John B]

Generally speaking I find HSS more useful and verasatile as you can grind cutting edges, forms etc to suit your requirements,

Carbide tools are more prone to chipping, and difficult to regrind, you need special grade wheels and diamond laps to do them properly.

They also require higher speeds to cut efficiently, and either none or copious amounts of coolant when cutting.

I am not familiar with your make or model of lathe, but generally speaking, any size of tool can be used so long as it is set to cut at centre height, and securely held.

[aametalmaster]

Looks like you need one of my square tool blocks. Then you can use any cutter you want from any size HSS to 1/2" sq shank carbide jobs. I used my lantern post once just to make my square block then it went in the drawer...Bob

[saintjohnbarleycorn]

I am also a very beginner, I went with the quick change tool post, and with it came some carbide bits. It was nice to actually see the tool cutting nicely, as opposed to me trying to grind the hss steel ones. BUT I will learn to grind them and use them, I suppose you will find out what works best for you, in the end. Believe me there is a whole lot to learn, as mentioned the speeds which I don't have any handle on as of yet, but it is a great learning experience! good luck.

[keithh999]

well since you mentioned it Bob i think ill have to make one of those tool posts...ive got to make a new angle plate for the milling attachment i just bought locally for $75....i have to bridgeport milling machines at work so that shouldnt be a problem. and then ill be able to use any or all of the oversized tooling we have at the shop. guess ill have to put a pic or two under "it followed me home" LOL

[aametalmaster]

Keith, Here is a few more pics of making my block.
Pic 1 scribing center line with dead center
Pic 2 t nut turned from round stock and the ears cut off to fit into the compound slot
Pic 3 t nut slid into slot. It also has a 5/8" 4130 stud threaded into it. The square block is recessed to fit over the stem sticking up...Bob

[arftist]

The nine inch south bend is a very popular lathe these days among hobbists. It is a slow turner and therefore hss tools are appropriate. Grinding single point tools is not that difficult. Rough with a hand held grinder, finnish on belt sander or bench grinder, hone on hand stone. If you have a lathe, and don't know how to grind tools buy a book about lathes or general machine shop practice. The clearence angles can be set using the table angle adjustment one the bench grinder or belt sander. I personaly use all three style tool holders shown, depending on the nature of the job.