Lathe tools

I am about 50 years behind in my tooling and I like it that way. When I buy 5/16" carbide tool bits they do not work for me as there is not enough front rake on the tool bit. I use the old fashioned tool holders straight, left and right that set the cutter bit at an upward angle whereas the carbide bits want to be flat level. What alternatives do I have?

Just add shims under tool bit to get it flat and level, also
If u can find a square indexing tool post that is right size for lathe

Your best bet, to do it right anyways, is to get a face grinder, with a green wheel, and regrind the bevel on the cutting edge. This way your not relying on shims, or anything else but the tool holder, to keep the bit stable and in the correct position. I used to do this when I had an old Southbend that still used the lantern post style tool holder.

I put up with that for awhile before spending a few bucks and buying a QC tool holder from Wholesale Tool. Having that made changing tools much easier, as they were already on center, and usually ready to use with just the turn of a handle. I moved on to a different lathe, that I got from my Dad last year, and it had all of the QC stuff with it. having been used to it, getting away from it for awhile, and now having it back, there's no way I would ever do without it again. The time spent messing with the lantern post, centering tools, etc, etc far exceeded the cost of a new tool holder, at least in my use for the business.

Ted,
Carbide tools use less of an angle on the cutting edge and sometimes a positive angle for top rakes. Carbides are great if they have a lot of support and a rigid machine but they are hard on older lathes with cast iron ways. Those cutting angles also take a lot more power. Are you talking about a bit with a brazed-on carbide edge or inserts. Unless you're doing a lot of volume or cutting something really hard stick with high speed bits. Custom grind whatever shape you can imagine. If you're looking to change to indexable carbide take a ride in to HGR in Euclid or check their website. It's in the old Fisher Body plant.

Mikes got the right scoop. Carbide is near useless on the old, smaller lathes like the Atlas, Dunlop, Craftsman, little Myfords, Unimats, etc. You need a rigid lathe with a strong, rigid tool post. For the older, small lathes go with high speed steel and learn to grind your own. Lots cheaper, better finish, no chipping. 5 feet of HSS can be had for the price of one of those insert carbide sets from India. Or you can buy preground sets online.

When I ran into this problem a number of years ago I bought import carbide tool holders made for standard square brazed carbide bits. They were Armstrong style for a rocker tool post and had the correct angle for standard brazed carbide tools. At the time they weren't that expensive. They work fine. My lathe is a Rockwell, nothing special, and uses 1/4" square tools (5/16 is just the next standard size up). You may have to shop around a bit to find them these days but with the Internet that's not a big deal.

There are a bunch of different insert types with just about any rake you can imagine. Course changing your toolpost may be better.

I use the 5/16 toolbits in my mini lathe. The cmt style works well but the flat carbide bits don't. Mine is a flat toolpost though.

Hobby machine tools, the ones that actually get used anyway, are about the hardest thing to quit spending money on that you will ever own. Everyone (including me OK?) wants the quick, easy, best and cheap way to make chips. Sorry to say that 25 plus years of home shop machining has taught me it don't work that way. I am not saying that any of the other posters here are wrong. People differ in how much time and effort they want to put into a $10 part. Myself I am past enjoying spending all day making a part that can be made in a hour with the right tooling. I am also past spending my time grinding tool bits for common jobs and screwing around resetting tool heights each time I change tooling.
With that in mind here is what I would do. First thing is to rid yourself of that rocker tool post and get a quick change. Probably a size AXA, you can get these complete with a set of holders for around $100 for an import from places like Shars, or spend upward of $1000 if you need made in USA stamped on the tag. The second thing I would do is quit fooling with brazed carbide bits and purchase a set of inserted holders with the proper shanks for the lathe and quick change. Again, very economical if imported or $$$ if you want top notch USA made. Fully 99% of lathe work can be done with the common and cheap tool holder sets, RH, LH, cut off and threading. The rest is preformed with custom ground HSS.

Other posters are correct about lathe loading with carbide,, when the wrong type is used. However with the correct type there is very little difference. Most certainly a correctly spec'ed carbide insert will cut easier than a dull HHS bit. Some people can sharpen HSS,, most cant, or wont, that is just my experience. Basics of carbide for light machine tools is you want Positive geometry and small corner radiuses. A good supplier only needs to know you are working with a small bench lathe.

Speeds and feeds are basic to doing good machine work on any type machine. I have run carbide on the lightest of light lathes with perfect results, it just takes the correct geometry, the correct feeds and correct speeds.

I will conclude with this. If spending $300 to get into it proper is not in the picture that us understandable but if that's the case you should forget about carbide and learn to sharpen HSS and be happy with it, brazed carbide is a waste of money and time, period.

HGR is a cool place to visit for sure!

Im with Butch on this. Get some indexable carbide too holders, couple that with a KDK style quick change tool post, and you are good to go. There are many types of inserts available, finding the right one for the material can be confusing but the salemen at MSC and other suppliers can set you straight. I still like to use HS steel for cutting plastics, but for everything else I used carbide in my 12x36 Wooster from around 1910

Butch has it nailed--indexable carbide inserts and a QC toolpost are the way to go. Use this setup on both my little 7x12 and my old South Bend. Never had problems with rigidity on either. Yes, I can grind my own toobits from blanks. I can also grind my own drill bits from blanks, but I'd rather buy them ready-made...... Enco is another good resource. 22 bucks gets you a set of 5 holders and 3 bucks apiece for the inserts, with 3 edges on each--they'll last a LONG time if you're sensible about speeds and feeds. Yes, there are times when grinding a special-use toolbit makes sense, but it's a very small percentage of time, and more hassle than it's worth for the vast majority of turning.
insert holders at Enco.

If you guys have found insert type tooling that works with the little lathes, I sure would like to the brand name. I've got several sets from Enco, Grizzly, etc and they were useless in my old Atlas 6". And yes, I have an upgraded heavy duty (for the size) tool post.

Bret: I use the ones I linked below in 3/8" shank size with TiN-coated C5 inserts (Enco 340-1200, if memory serves) for most work. That's what works for me on my equipment, but as you can see from the replies, I'm hardly alone--there's a good number of people across a wide spectrum of small machines that use this same basic approach with success. Yes, it takes a different approach than HSS bits, and it's less forgiving of errors in bit height, speeds, and feeds (I've snapped a couple inserts off the holders when I got it wrong) but it DOES work, and you CAN use it on a small lathe with success. I've got drawers full of HSS stock and brazed bits, but, with the exception of a very occasional time when I've got to have a certain profile or a particular piece of stock just WON'T cooperate, they stay in their drawers. I'd rather use bits I know are designed with the correct angles and made to be repeatable time after time than rely on guesstimating them myself and having to keep fiddling with adjustments to get proper results. Again, this is what works for me--while I have a pretty fair grasp of the general theory behind bit grinding, and have done enough of it to be able to make specialized profiles where needed, it's not something I prefer to spend my time doing--I'd rather spend a couple bucks to get something I KNOW is properly designed to do the job and spend my time making the actual parts.

As Tim said it is a bit more complicated than switching the tooling. Surface speeds must go up, feeds must go up or poor finishes will be the result. Link is similar to the tooling I used on my small lathe.
Small lathe tooling

(quoted from post at 14:39:43 11/10/15) As Tim said it is a bit more complicated than switching the tooling. Surface speeds must go up, feeds must go up or poor finishes will be the result. Link is similar to the tooling I used on my small lathe.
Small lathe tooling

Click to expand...

What's the swing on your lathe?