Drilling Stainless Steel

Learn to sharpen bits. For anything under 10 mm this should take well under a minute. Some of mine are nearly a century old. They're shorter than they used to be.

Coolant. If you don't have coolant, at least use oil.

If it does no make nice chips on contact, sharpen it. Also, don't for get pilot drilling. This is particularly helpful for larger sizes without a drill press, since it is impossible to get sufficient feed pressure in many geometries.

Curiously, I seem to have less trouble on the lathe than drilling. The reasons are that the lathe tends to use a small cutting edge, I am focused on chip formation, and it is easy to regulate all of the variables.
 
Learn to sharpen bits. For anything under 10 mm this should take well under a minute. Some of mine are nearly a century old. They're shorter than they used to be.

Coolant. If you don't have coolant, at least use oil.

If it does no make nice chips on contact, sharpen it. Also, don't for get pilot drilling. This is particularly helpful for larger sizes without a drill press, since it is impossible to get sufficient feed pressure in many geometries.

Curiously, I seem to have less trouble on the lathe than drilling. The reasons are that the lathe tends to use a small cutting edge, I am focused on chip formation, and it is easy to regulate all of the variables.
On a lathe one can be cutting new material & apply pressure at a continuous feed rate. This stops case hardening. This applied with suitable lubricant makes a difference. Correctly selected modern tipped cutters run at the correct speed & feed is essential if HSS bits are not used. If they are then corect bevels should be followed & many guides are avaiable. Chips need to be small for safety reasons
 
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Learn to sharpen bits. For anything under 10 mm this should take well under a minute. Some of mine are nearly a century old. They're shorter than they used to be.

Coolant. If you don't have coolant, at least use oil.

If it does no make nice chips on contact, sharpen it. Also, don't for get pilot drilling. This is particularly helpful for larger sizes without a drill press, since it is impossible to get sufficient feed pressure in many geometries.

Curiously, I seem to have less trouble on the lathe than drilling. The reasons are that the lathe tends to use a small cutting edge, I am focused on chip formation, and it is easy to regulate all of the variables.
I have a drill bit sharpener (although a grinder is just as effective).....but I find them to be close to useless for anything other than soft materials.....I think it’s because you are actually grinding off the hardened surface
 
We have a decent small machine shop in our business. I watched our hoary old toolmaker drill some holes. He used a milling machine set really slow, maybe 100 rpm, a hss drill and a very slow steady feed, lots of coolant. He made it look really easy. He also has a good surface grinder adapted to sharpen drills, so the drill was absolutely pucker.
 
If I was drilling- for example- a 5/16 hole in 1/4 304 stainless on a mill, I would flood with lubricant & run at 500-600 RPM & use a decent hss drill, properly sharpened with double faucet. Not on some cheepo sharpening tool, or hand sharpened effort. Use plenty of pressure & not alow the bit to rub, especially at the end where incorrect use will damage the ears of the bit. One can drill numerous holes before touching up the drill
Smaller diameters best run at slightly higher speed.
 
I have a drill bit sharpener (although a grinder is just as effective).....but I find them to be close to useless for anything other than soft materials.....I think it’s because you are actually grinding off the hardened surface
At least on a HHS drill, the entire drill is hardened. They should cut the same after sharpening, if the angles are correct.

It takes practice. I couldn't do it well when I was young, even with a sharpener. Now free hand is second nature. Every operation takes time to master. Lots of mistakes, unfortunately, but then you try a different way.
 
Learn to sharpen bits. For anything under 10 mm this should take well under a minute. Some of mine are nearly a century old. They're shorter than they used to be.

Coolant. If you don't have coolant, at least use oil.

If it does no make nice chips on contact, sharpen it. Also, don't for get pilot drilling. This is particularly helpful for larger sizes without a drill press, since it is impossible to get sufficient feed pressure in many geometries.

Curiously, I seem to have less trouble on the lathe than drilling. The reasons are that the lathe tends to use a small cutting edge, I am focused on chip formation, and it is easy to regulate all of the variables.
You mean "coolant" as in ethylene glycol/water antifreeze, or as in a "cutting oil" water/(vegetable?) oil emulsion?

Hadn't heard of the former being done, and wouldn't normally have had any handy, since it was in the (car) engine, but now I dont have a car, but bought antifreeze as a wood treatment, so I could easily try it.
 
You mean "coolant" as in ethylene glycol/water antifreeze, or as in a "cutting oil" water/(vegetable?) oil emulsion?

Hadn't heard of the former being done, and wouldn't normally have had any handy, since it was in the (car) engine, but now I dont have a car, but bought antifreeze as a wood treatment, so I could easily try it.
Cutting oil emulsion. Also stainless cutting specialty products (I don't know UK brands).

Not engine coolant in this context.
 
Rooster do a Laser block eye with larger holes in case you need larger rivets.

Pre Drilled to 1/4" Laser/ILCA boom block attachment Lac...

It would be convenient for me to buy a standard one and drill it myself if I need to.

Am I right in assuming that's all Rooster did and if they can do it, I can do it to? (I imagine stainless to be brittle and resistant to drilling?)
5 days later and did you drill it ? If so how did you get on .............
 
5 days later and did you drill it ? If so how did you get on .............

Not yet. I was busy every weekday evening. I set aside this morning to do it but I've had to take my lad to an event. I'll drill the rivets this afternoon and measure the holes. Then if I need to I'll drill the existing one and depending on how that goes I'll order the necessary new one(s).

I'll try to take photos. :)
 
So, it went really well. The topic should perhaps be "Laser boom refurb" rather than, Drilling stainless.

Anyway, the only stainless steel drilling I needed to do was the rivets. And the advice in the thread was really useful. Used sharp HSS drills and lubed with Olive Oil. It wasn't easy, but it worked. The strategy to drill spinning rivets at 30 degrees turns out to be utter lies! I devised various ways to hold a rivet spinning. None pretty. 😁

Measured the holes.

BOOM =======MID========== CLEW =

MID block, both 5.3mm.
CLEW block, 5.3mm and 5.5mm
Both holes on the "loop fitting" are 5.4mm.

I'd been thinking none of this would matter if I could just use bolts, but clearly that's impossible on the mid boom block. But than... As luck would have it as I was googling the Rooster site for the dimensions of the standard "loop fitting" to decide the best rivet/loop hole sizes I found this blog article:

The Laser Boom - Bolt it up! (From the Rooster Archives)

It introduced the idea of mousing the bolts through. So all of a sudden bolts were on the agenda. Mousing bolts through seemed pie in the sky to me, but I figured the price of a new end plug was a worthwhile bet, saving me the hassle of buying a heavier duty riveter than my own and working the right rivet sizes for the various holes - and then drilling the loops. Anyway the first bolt went with a minimal amount of persuasion and I knew it was going to work. The second was an absolute pig, but by then I knew it would go in so I stuck with it.

So now instead of sourcing larger stainless rivets, heavy duty riveter and an outsized loop fitting I can buy the standard loop fitting, end cap and simply bolt it on. Result.

Shook the old bits of rivet and a stone out of the boom. I drilled 4, and 5 rivets slid out. :)

So, thanks YBWers. Much appreciate the help. First two photos are the mod boom fitting bolted on woth nylock nuts.

20250906_192039.jpg20250906_191716.jpg20250906_152459.jpg20250906_143729.jpg20250906_144207.jpg20250906_143018.jpg
 
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So, it went really well. The topic should perhaps be "Laser boom refurb" rather than, Drilling stainless.

Anyway, the only stainless steel drilling I needed to do was the rivets. And the advice in the thread was really useful. Used sharp HSS drills and lubed with Olive Oil. It wasn't easy, but it worked. The strategy to drill spinning rivets at 30 degrees turns out to be utter lies! I devised various ways to hold a rivet spinning. None pretty. 😁

Measured the holes.

BOOM =======MID========== CLEW =

MID block, both 5.3mm.
CLEW block, 5.3mm and 5.5mm
Both holes on the "loop fitting" are 5.4mm.

I'd been thinking none of this would matter if I could just use bolts, but clearly that's impossible on the mid boom block.

As luck would have it as I was googling the Rooster site for the dimensions of the standard "loop fitting" to decide the best rivet/loop hole sizes I found this blog article:

The Laser Boom - Bolt it up! (From the Rooster Archives)

It introduced the idea of mousing the bolts through. Seemed pie in the sky to me, but I figured the price of a new end plug was a worthwhile bet, saving me the hassle of buying an heavier duty riveter than my own. Anyway the first bolt went in a minimal amount of persuasion. The second was an absolute pig, but by then I knew it would go in so I stuck with it.

So now instead of sourcing larger stainless rivets, heavy duty riveter and an outsized loop fitting I can buy the standard loop fitting, end cap and simply bolt it on. Result.

Shook the old bits of rivet and a stone out of the boom. I drilled 4, and 5 rivets slid out. :)

So, thanks YBWers. Much appreciate the help.

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Which bit is the stainless ?
 
I have a drill bit sharpener (although a grinder is just as effective).....but I find them to be close to useless for anything other than soft materials.....I think it’s because you are actually grinding off the hardened surface
What hardened surface? HSS Drill bits are the same material right through. I have been sharpening my drill bits since I was shown how in the mid 1960's.

Some of the best bits I have were from China, imperial sized HSS set in a three row folding box. I worked where they sold them, bought two sets in 1983. Still got them, used frequently too on S/S!
 
Given the difficulty of fitting I suppose you might not have isolated the SS from the aluminium all that anally, and at a wild guess wont be very keen to take them off again to re do.

Maybe soak them with something penetrating. WD40 will leave a little wax, and your olive oil would eventually polymerise to form a pseudo-plastic coating, though I'm not sure how effective that'll be.

I'd probably do both, then mineral oil, successively at long but fairly regular intervals.

At least thats what I'm telling myself.
 
Given the difficulty of fitting I suppose you might not have isolated the SS from the aluminium all that anally, and at a wild guess wont be very keen to take them off again to re do.

No, I did nothing whatsoever. The thought briefly floated into my head of the time my exhaust studs welded themselves into a alloy head. I chased those disturbing thoughts away and carried on.

I also gave no thought to how I would ever remove them if required. 😬 Angle grinder and a great deal of care I guess.

How much of a problem am I storing up for myself?

It would be very easy to dribble oil in there, the join is far from water tight. Of course where the contact between metal is tightest I'd guess none will get in. But it could help. I could do that a few times a season, (until I stop bothering one day). 🤔


EDIT: Just googled. What a plonker. 😭
 
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