Making carbide turning tools

[BearTricks]

I’ve been looking in to getting carbide tools but know someone who’s business buys the cutters by the bucketload and is willing to spare some. They’re identical to the replacement cutters sold in places like Axminster and Rutland’s.

I also have some HSS blanks, enough hardwood spindle blanks to make a handful of handles, and a tap and die set. I was looking at some of the more expensive carbide tools earlier and thought it’s probably only one step beyond making a HSS tool which I’ve done in the past.

Is making one as simple as threading a hole in the HSS blank, grinding a profile to support the cutting edge, screwing the cutter on, and whacking a handle on it or do they have a more complicated holding mechanism to prevent the cutter flying off and doing some serious damage?

I’ve only ever used HSS tools; I’ve seen carbide ones in person but never paid attention to how they’re held together.

If anyone has any photos that would also be great.

 

[Phil Pascoe]

You don't need hss, bright mild will do. This was experimental, hence the hexagonal bar.

 

[Roland]

Is making one as simple as threading a hole in the HSS blank, grinding a profile to support the cutting edge, screwing the cutter on, and whacking a handle on it …

Yes.

 

[ChaiLatte]

Why don't you find some photos yourself and look and think how the tools are constructed?

https://www.rutlands.com/collections/carbide-turning-tools

Your post reads a little as if you are wanting to fix the carbide insert to the HSS. As above, that is not necessary and a waste of HSS. You will not tap a hole in HSS. The piece of metal that supports the carbide insert (the square section with Rutlands written on it in the link above) is just normal steel. Even in a metal cutting lathe, it is nothing too special, just a tough, wear resistant steel.

The Rutlands ones do not use an insert pocket, but if you want to go in that direction, you might get some inspiration from how the inserts are held in metal lathe tools.

This is a gentle introduction. You do not need to read much beyond numbered paragraph 1 for what you are proposing:

https://www.cutwel.co.uk/blog/learn-the-turning-tool-iso-code-system.html

Two things to take away:

1. every metal cutting insert sits in a pocket that is shaped to support the (back of) the insert so the cutting forces push it into the pocket.

2. some inserts do not have a hole in them and are held into the pocket with a top clamp.

 

[ChaiLatte]

Yes.

You quote the OP, but I fear you may not have properly read what you are quoting. Please read again: "Is making one as simple as threading a hole in the HSS blank".

Are you really agreeing that he should be tapping (threading) a hole into a piece of HSS?

If you have watched the video, perhaps you could comment on what material is shown on the right hand side of the screen shot. It is by no means HSS (has anyone ever seen HSS sold in long sticks like that?).

 

[Sachakins]

Yes, BUT NOT HSS. Just some bright mild steel square section.
To make it easy, ensure the square bar is slight narrower than the insert piece you use.
You can also use round bar if you want.
Round bar is easier when you are making one as a shear scraper.

 

[Owd Jockey]

Hi BearTricks, I made 3 Carbide tools, to house the three most common cutters (round, square & diamond detail). I used 10mm square mild steel. If you want a 'beefier' tool go up to 12/16mm square mild steel. I have one bought carbide cutter with round bright steel, which is used for deep vase work, but is of limited value, the square mild steel obviously gives better support. Care must be taken to get the right profile at the tool end to ensure the cutter can do its job, careful use of a flap-wheel/ file is called up here. Don't forget your small piece of 20mm copper pipe for your ferrule and try and source your handle in a bit of decent hardwood

 

[Sachakins]

Some close up of my tips

 

[Vulcan]

It depends on what tools you have but no, they aren’t difficult to make. Pay attention to the fasteners though. Even some of the commercial tools don’t always use the best ones. I recommend using proper insert Torx screws. The round cupped ones use standard insert Torx screws. The square, and larger round flat inserts use a type of Torx screw that is not so easily available. You can use ordinary screws but it’s not difficult to crack an insert if you over tighten the wrong type of fastener.
A couple of my hollowing tools with 6mm inserts.

 

[Vulcan]

I’ve just recently come across this site. They not only sell carbide inserts but also the correct type of screws for them as well.

https://www.ridethebevel.co.uk/

 

[CliveB]

The Torx screws for many of the insert types should be one with a 60 degree taper which matches the internal taper on the insert - see Torx screw taper. This will keep the insert secure.

 

[Vulcan]

The Torx screws for many of the insert types should be one with a 60 degree taper which matches the internal taper on the insert - see Torx screw taper. This will keep the insert secure.

There are at least two different countersink angles used on carbide inserts. Metal cutting inserts such as the *RCGT types for example have a steep angle.
The larger square inserts from planer heads have a much shallower angle.

You can see the difference on this page:

https://www.ridethebevel.co.uk/index.aspx?pageid=1vNgc&category=233167

* Sharp versions of the RCGT inserts with an AK suffix, originally designed for cutting light alloys and plastics, work really well for hollowing.

Edit: This clearly shows the difference.

 

[Hornbeam]

You don't need hss, bright mild will do. This was experimental, hence the hexagonal bar.

Was it messy opening the tin

 

[CliveB]

There are at least two different countersink angles used on carbide inserts. Metal cutting inserts such as the *RCGT types for example have a steep angle.
The larger square inserts from planer heads have a much shallower angle.

You can see the difference on this page:

https://www.ridethebevel.co.uk/index.aspx?pageid=1vNgc&category=233167

* Sharp versions of the RCGT inserts with an AK suffix, originally designed for cutting light alloys and plastics, work really well for hollowing.

Edit: This clearly shows the difference.

View attachment 176143

Thanks for this clarification, I also use an RCGT tip (6mm polished type designed for aluminium) for hollowing - works extremely well and lasts for ages. This holder is made from 12mm dia silver steel (unhardened) held in an ER20 collet chuck. The shelf holding the cutter looks looks a little thin but it has withstood a lot of abuse without bending.

 

[Vulcan]

I’ve enjoyed experimenting with carbide inserts over the years. I’ve not tried a square insert yet but it’s on the to do list, I’ve had the inserts a while.