Drilling into HSS - again

[graduate_owner]

Hi all,
I have read several articles about this topic and there seems to be some disagreement. Some people say solid carbide bits will do the job, others have said they won't, and similarly for tungsten carbide tipped bits.
I was thinking of drilling into the axis of an old, blunt milling machine cutter, then using an angle grinder to slice discs off with the hole more or less centred.
What do people think of the feasibility of drilling a milling cutter - will that be too hard for cobalt drills? What about the diamond tipped drills used for drilling porcelain? Does anyone have any better ideas? I don't fancy annealing and then hardening as this seems to bring its own set of problems.
Is a milling cutter likely to be just too hard - Would I be better off using a round bar of HSS from ebay instead?

The purpose of this is to make my own wood turning tools as sown in this video.
https://www.youtube.com/watch?v=Jdhnm6biC

If this is going to be a right performance then I will scrap the idea.

K

 

[oakmitre]

The angle grinder will produce plenty of localised heat, especially if you are cutting thinner pieces off.

 

[woodpig]

I'm given to understand you need specialist equipment to reharden HSS even if you could soften it enough to cut it more easily. I can't open your linked video to see what you're trying to do but have you thought of using carbide inserts instead?

 

[woodfarmer]

I wonder if a carbide tipped drill as used for holes in bricks might work. may need reprofiling to cut steel. either way use very low speeds.

I use hss on en316l often and using very low speeds makes a huge difference to how much work I can do.

 

[Robbo3]

I asked the same question in this thread. I now have a set of Artu drills which are supposed to go through nearly anything including HSS
- two-questions-drilling-hss-lathe-lubrication-t62152.html

Not sure what tool(s) you are trying to fabricate but this thread is similar to the above on a thin parting tool
- make-your-own-thin-parting-tool-t64760.html

There have been several threads on making deep hollowing tools but I haven't kept a record of them & there is probably no need of HSS in their making.

I bought a spare 16mm bar that fits the Big Brother tool (IIRC & because it was cheap) which came with a flat ground across the end fitted with socket screw. I then added a commercial scraper tip purely because of the thickness of metal it was made from.

Edit : I forgot to say that I tried TCT glass drills which shattered on breakthrough & a cobolt tipped bit which wouldn't touch HSS. TCT masonry bits worked fairly well after sharpening on a green wheel (Chronos sell them).

 

[woodpig]

There are dozens of different types of inserts on the market made from all kinds of materials including HSS and Carbide. I you really want to make your own for any reason you can use carbon steel like O1. It's easy to shape in its annealed state and easy to harden afterwards. They won't stay sharp as long as HSS or carbide but perfectly usable and cheap to make.

 

[chaoticbob]

I was going to say that I've turned HSS (OK tho not pleasant) with carbide, so drilling should work - but just went down to the workshop to check before posting. I picked up a random bit of HSS and had at it with a solid carbide spot drill. Couldn't get a bite at all. Perhaps it depends on the specific grades of HSS/carbide, and maybe that's why the results of your researches are inconclusive.
I'd agree with woodpig though - O1 (gauge plate) or silver steel are much easier to work with, hardening is easy enough and they'll take razor edges.
Rob

 

[Robbo3]

Correct link to the video (I think). So now we know what you are trying to do.
- https://www.youtube.com/watch?v=Jdhnm6biC1o

IMHO a round bar is better. Moves over the toolrest easily & when rolling sideways to get a better cut, it isn't resting on the corner of the shaft. It also doesn't need a tang, just drill the handle to suit or better still use a collet handle. Collets come in various sizes to suit a range of commercial & home made tool shanks. You could make your own collet handle - see Youtube again.

 

[woodpig]

I've seen that video before. The "tool steel" he's using is almost certainly Silver Steel as he's turning it with a HSS tool bit.

I've made several turning tools and bought some of the inserts here:

http://www.ukwoodcraftandcarbidechisels ... tters.html

Modern micro carbide works well on wood and holds an edge for ages.

 

[Rorschach]

I've turned HSS using carbide, never had any success drilling though, most carbide drills are just too brittle and chip or snap quickly. You might have luck with a modified carbide tipped masonry bit but since I have never had need to do this kind of thing I can't give any advice.

 

[Northern woodworm]

Due to it being harder than other steels I would have thought that drilling with standard drills would be a bit a of non-starter. I have had some success in the past drilling very hard ceramic with a diamond grinding drill bit so with a lowish speed it may work on hss. There pretty cheap from screwfix too.

 

[Rorschach]

Due to it being harder than other steels I would have thought that drilling with standard drills would be a bit a of non-starter. I have had some success in the past drilling very hard ceramic with a diamond grinding drill bit so with a lowish speed it may work on hss. There pretty cheap from screwfix too.

You need to keep it really slow, if the diamonds heat up too much they will dissolve into the steel.