HSS lathe tool types

Please can someone tell me the specific purpose of the third tool from the left and the difference in purpose/application of the form 4 and form 8 tools.

Thanks.

Haven't really got a scooby. The point angle looks too small for screwcutting - except maybe BA?

That's why I generally buy square-section HSS blanks and grind 'em to whatever form I like.

Most seem to list it as "straight finishing 60/55deg" so I would say it's just a knife tool for detail work as the same sets have separate threading tools.

Why not phone Amadeal and ask Hugh what it is.

No4 is Chamfer

No8 a threading tool

Edited By JasonB on 05/07/2023 19:03:06

Thanks for the answers.

This link calls form 8 "a corner tool" suggesting, to me at any rate, that it's intended as another chamfer tool, like form 4. Both form 4 and form 8 in my set have 90 degree tips. What the essential difference is I don't know.

The 60 degree external threading tool is the second from the right [form 7]. There isn't a 55 degree tool in the set, or an internal threading tool. Am happy to have a go at making these when/if needed.

I'm not sure what a finishing tool is [for taking very light cuts and producing a good surface finish?]. In my set, the third from the left has an included angle of 40 degrees, so I don't see how it can be used for threading. But it looks like it would be very good for chamfering in very tight spots.

Amadeal are closed for business until 12th July.

Edited By Bill Phinn on 05/07/2023 20:41:10

Have a look at the warco set it gives the names of the tools in the set

The 40 deg pointed tool (number 3) is just right for making the grooves in pulleys to take poly "v" belts. Otherwise it is a tool for getting into tight places that other tools cannot reach.

Thanks for the further answers.

Dalboy, the two Warco diagram pages give the names of some of the tools in my set. However, the actual selection of tools shown and named in those diagrams doesn't correspond exactly with either the tools I have or the tools Warco have shown in the accompanying photographs!

Incidentally, there is clearly disagreement in the industry over which is a left hand turning tool and which a right. Arceurotrade's naming convention is the one I follow, but Garvin Tools [linked to above] and others I have seen reverse this.

Edited By Bill Phinn on 05/07/2023 22:32:15

Not sure if you have your tongue firmly in your cheek Bill, but in case not the 'others I have seen link' (Myford aka RDG) advertises an LH tool with a picture of an RH tool. Scrolling down they show the corresponding RH tool with - erm - exactly the same image.

Robin.

Maybe you can swing tool 3 Left-Right a bit in the toolpost or the whole toolpost to get more use for it like a wide groove Left-Centre-Right, or near a live centre where space can be a problem.

Edited By Chris Mate on 05/07/2023 23:23:13

As Chris says don't feel restricted to mounting the tools at right angles to the axis of the lathe.
A 'finishing tool' is to differentiate it from a 'roughing tool'.
A roughing tool is often shown as looking a bit like No4 and with a rounded tip. This is to avoid a fragile sharp point that can break or overheat and so that the forces are diagonal pushing out on all the lathe top, cross, and feed screws to avoid chatter. This tool is used by the gorilla in the workshop but may leave a rough finish and no sharp inside corners because of that canted over leading side.
Then the finishing tool has the necessary sharp point to get into the corners, a small radius to avoid a stress raiser and provide enough strength if used carefully, and maybe a small flat on the tip parallel to direction of travel to prevent the finishing pass looking like a very fine thread.

RDG are just using generic images for a range of tools. the one in the link is showing an SCLCR holder where the last "R" signifies it is for right hand use. ARC have it engraved onto the tool

I must admit to also having come across all these names/ideas etc, and like Mick B1 above, I long since stopped buying pre-ground tools as I invariable ended up either not using, or regrinding myself. For most of my turning, I have tended to use the tool which cuts when moving towards the headstock and thus has it's cutting edge on the left hand side of the tool, and which I know as a Right Hand Turning tool. What's in a name though?

It's worth pointing out that the RH Turning tool can be used, if canted over somewhat, as a facing tool as well. (Shock, horror, gasp etc). Hence, I can get away with a lot of my external turning with just the one tool.

I may as well point out that some years ago, I started using carbon steel tools as well, old files actually, softened, cut up, reground, and then re-hardened. Ok, they don't last long before requiring re-sharpening, but hey, the material is free, ie worn out files.

I do have a set of HSS tools hidden on a shelf somewhere, but never used. Why? Because I never seemed to need to use them given what I already have. But, I did make one mistake with this set - I bought 1/2" or 12mm square shank tools as the lathe was able to take them. A further and much bigger "but", is the amount of regrinding tools of this size take! So, don't buy the biggest tools your lathe can take: for our purposes, 1/4" or 6mm square tools are perfectly adequate - yes you will need packing to get the cutting tip at the correct height, but sharpening/re-grinding is so much easier, there being less material to remove.

I haven't really bothered about the distinction between roughing and finishing. I think it was Tubal Cain, (T.D. Walshaw) or maybe L.C. Mason who said that the average ME never uses the equipment at rates requiring a roughing tool, so I always sharpen mine as a finishing tool. I did once do some experimenting to see what the lathe could handle. Never again. The lathe was happy, but I wasn't given the amount of smoke generated by the cutting oil. So another reason for lightweight cutting.

So, there you are, my thoughts, strictly as a very amateur, amateur.

Happy turning,

Peter G. Shaw

Not any more, Robin; RDG/Myford clearly read this forum.

Here's the cached page for now, though.