Best drill bit for stainless steel

[Jamie Leask]

I need to drill out a 32mm hole in a stainless steel bar (4 - 6mm) What is the best type drill bit for a normal combi 18v drill.

 

[ShaunCorbs]

Tct but you can make do with a bi metal hole saw and some cutting oil but speed 1 and take your time prob around 20-30 mins a hole

 

[centralheatking]

Tct but you can make do with a bi metal hole saw and some cutting oil but speed 1 and take your time prob around 20-30 mins a hole

Hss very slowly with plenty of oil start off with a small dia and work your way up to about half dia, then go for it , nice new sharp drill loads of oil. How many are you doing ? there are electro magnetic type bench drills you can hire for site work. centralheatking

 

[Jamie Leask]

Tct but you can make do with a bi metal hole saw and some cutting oil but speed 1 and take your time prob around 20-30 mins a hole

Ok cool thanks I like the sound of this. So basically a hole saw but for metal instead of wood, and then you get different sizes instead of just one.
[automerge]1576523289[/automerge]

Hss very slowly with plenty of oil start off with a small dia and work your way up to about half dia, then go for it , nice new sharp drill loads of oil. How many are you doing ? there are electro magnetic type bench drills you can hire for site work. centralheatking

mate it’s just one for a monobloc tap.

 

[ShaunCorbs]

Ok cool thanks I like the sound of this. So basically a hole saw but for metal instead of wood, and then you get different sizes instead of just one.
[automerge]1576523289[/automerge]

mate it’s just one for a monobloc tap.

Yes will be listed as bi metal go Bosch or starrett

Get two not just one incase you hit a hard spot

 

[Jamie Leask]

Yes will be listed as bi metal go Bosch or starrett

Get two not just one incase you hit a hard spot

Yip Ill

Yes will be listed as bi metal go Bosch or starrett

Get two not just one incase you hit a hard spot

have you ever used a step drill , this type of thing. No idea if it’l just melt

 

[ShaunCorbs]

Not on thick stuff max I would go is like 2-3mm any more it doesn’t fully work you have to do it both side etc

 

[rpm]

Do not try a step drill with stainless steel, use the correct size drill and take one slow go at it.

 

[gmartine]

Not bad for £12 if you have a RS nearby, the right sized hole saw (if you dont have one) will cost near enough the same.

RS PRO Tungsten Carbide Tipped 32mm Core Drill Bit | RS

uk.rs-online.com

 

[Jamie Leask]

Not bad for £12 if you have a RS nearby, the right sized hole saw (if you dont have one) will cost near enough the same.

RS PRO Tungsten Carbide Tipped 32mm Core Drill Bit | RS

uk.rs-online.com

Cheers I’ll look into this and report back to yoi guys as I’m off to attempt it this morning

 

[Jamie Leask]

I need to drill out a 32mm hole in a stainless steel bar (4 - 6mm) What is the best type drill bit for a normal combi 18v drill.

So the outcome from the job was as follows. I used a step titanium drill bit 32mm as its widest. I started it off with a normal 8mm drill bit and then used the step drill. I also bought some WD 40 cutting oil. I was using my 18v Makita combi drill. I put it onto drill mode and the gear down to 1. The bar top was about 4mm thick. I went about it slowly taking mini breaks as my drill was getting very hot. The whole thing took about 30 minutes and was actually quite easy and the step drill bit really made quite an easy job. It would catch here and there but generally fine. In the end I needed to make it slightly wider (maybe 35mm in total) and I just used the same step bit to grind it out in a circle around the edge. In in all I would highly recommend this way of going about this sort of job. Thanks to anyone for the advice it was very useful!!

 

[gmartine]

Good job and thanks for the honest review but I just don't agree it's a suitable method to recommend for that material with that sort of thickness.

Sure it may do for a one time job especially if you already had some of the equipment BUT you took your time, used lubricant and pushed your equipment to the absolute limits. If you had more than one to do I think you'd struggle, with a step drill you obviously have to keep drilling consecutive holes to reach the diameter you want putting your drill under tremendous stress. Stainless steel is a pig for blunting tools that's why a carbide tipped tool would always be a superior choice in this situation. I spent a few of my early years as a machinist, hate stainless and once the bit coating is cooked or worn forget about it, well done again for getting it done but it's not one I'd recommend.

 

[Jamie Leask]

Good job and thanks for the honest review but I just don't agree it's a suitable method to recommend for that material with that sort of thickness.

Sure it may do for a one time job especially if you already had some of the equipment BUT you took your time, used lubricant and pushed your equipment to the absolute limits. If you had more than one to do I think you'd struggle, with a step drill you obviously have to keep drilling consecutive holes to reach the diameter you want putting your drill under tremendous stress. Stainless steel is a pig for blunting tools that's why a carbide tipped tool would always be a superior choice in this situation. I spent a few of my early years as a machinist, hate stainless and once the bit coating is cooked or worn forget about it, well done again for getting it done but it's not one I'd recommend.

Handbags

Good job and thanks for the honest review but I just don't agree it's a suitable method to recommend for that material with that sort of thickness.

Sure it may do for a one time job especially if you already had some of the equipment BUT you took your time, used lubricant and pushed your equipment to the absolute limits. If you had more than one to do I think you'd struggle, with a step drill you obviously have to keep drilling consecutive holes to reach the diameter you want putting your drill under tremendous stress. Stainless steel is a pig for blunting tools that's why a carbide tipped tool would always be a superior choice in this situation. I spent a few of my early years as a machinist, hate stainless and once the bit coating is cooked or worn forget about it, well done again for getting it done but it's not one I'd recommend.

As you can see from the original question. It was one hole I needed. Do you know what patronising means?? 😂

 

[gmartine]

Sorry you feel that way but our advice is usually based on experience and know how which you asked for and chose to ignore. No member recommended a step drill infact they catagorically advised against it and your description of drilling that hole just confirms why. You were fortunate not to cook your drill and we know what the limitations of a step drill are so hopefully readers do not heed your advice based on your one and only experience.

 

[tomdickey]

On hard to drill materials like stainless and tungsten steels its best done with a drill press or pillar drill (hand held drilling is more likely to wear or break drill the bits) with the work piece firmly clamped. Matching the rotational speed and feed to size of bit and the material to be drilled is equally important as most drill wear is caused by excessive speed and/or feed.