what tools (HSS)

Hi this is my first post.

I have recently acquired a Churchill Cub lathe and need some advice on some beginner tooling requirements. I have been instructed that I probably want HSS tooling as it may not be fast enough to get hi quality finish with carbide.

Many thanks

Jamie

Welcome to the forum Jamie.

Lots of advice on the pros and cons of HSS vs Carbide will be along shortly I'm sure!

As it's my bedtime and I get grumpy without 9 hours solid, have a read of this thread to be going on with.

Dave

YOu need one of these LH SPAREY

Everything you need is in there. Worth its weight in gold to any owner of an older lathe (or newer for that matter too).

Edited By Hopper on 10/02/2022 22:19:40

Hi Jamie welcome to the forum. Tool steel is very good and forgiving, less likely to chip but you have to have a way of sharpening it. A bench grinder is usual to sharpen tools and a cheap one can do the job but a better one with a better tool rest would be advisable. I don't know if you are aware of safety things like wearing safety glasses etc but dont let that put you off just think before you grind or machine anything. It helps yo buy ready made tools but evan they may need finish sharpening or slight adjustment. I don't know where you are but there may be someone local to you who may give you a few tips etc. Indexable carbide tools are available but can chip if not used properly or not set on center height. If you have a 6 inch rule and trap it gently between the job or side of a piece of bar in the chuck if it is on center it will be vertical if it is above center the rule will angle to the right, if it is low it will angle to the left. If you set an engineers square on the saddle it will give you a good guide to squareness. If you have any question just ask no question is daft if you don't know the answer but trial and error can be a learning curve.

David

Besides being able to get a really sharp edge, grinding your own HSS tools has the advantage of being able to make one at a moment's notice without having to wait for an order to arrive.

And I second Hopper's recommendation of the Sparey book.  It's a must-have.

Edited By MikeK on 10/02/2022 22:34:16

Jamie,

I think is is a good idea to start using HSS tools. You have to learn how to regrind and shape them. This is something that will be needed some time. HSS tools are also cost effective (if you don't calculate time). I spend yearly more on inserts than i totally spend on HSS tools.

When I took a shop course 1n 1955 we were not allowed to touch the lathe until we had ground our own tool bit. I think that is still a good idea. BTW I still have that tool. Many of the older charts show tool angles for use with holders that have 15* of back rake built in. The best chart I have seen for tool bits held flat is from Little Machine Shop. **LINK**

The Diamond tool holder from Eccentric Engineering (advertised here on ME) is a good option. It comes with a simple grinding jig making it very easy to sharpen the cutter with only a standard bench grinder and produces a quality finish.

Carbide tools used to be expensive in the past but globalization has driven the price to such a low level that I just dont bother to use HSS and do grinding and re-shimming from time to time. A carbide insert costs less than 3 lbs and the quality is good ( for me at least ). The only disadvantage of carbide tool is that they are more brittle and break more easily if you don't handle with reasonable care. 

The fact that carbide tools allow the use of higher cutting speed does not mean that you need to use that speed in order to get good finish. Thats a myth that I have believed in for some time. The use of lower speed just reduces productivity which is an issue if you are doing machining for a living.

Edited By Y C Lui on 11/02/2022 04:00:38

Hi Jamie,

Welcome to he forum. As has been mentioned a bench grinder let you grind your own HSS tools, you can then use a stone or diamond hone to get a sharp cutting edge. A tangential tool holder works well and it is easy to grind the tool bit, you can even make one yourself.

***Link*** and ***Link*** - about grinding lathe tools.

Thor

+1 for the Diamond tool holder from Eccentric Engineering. (See the advert to the right of this page.)

I bought one over 10 years ago when I started out and it is still my go-to turning tool for most materials. They are not cheap but you get the holder, a HSS bit, a grinding jig and an Allen key. All you need is a grinding wheel, which you will need anyway, and off you go.

I now also have some indexable carbide tools for cast iron and a carbide parting off cutter from Arc Euro which I use on most materials.

Hope this helps

Jim

+1 for HSS tool bits ! The only carbide inserts that I use is for threading, up until till recently when I was given a box set of brazed carbide tools. Currently unused and still in the box somewhere. Though I did buy a carbide insert tipped boring bar just to bore out a cast Iron pulley.