I'm concidering attaching ladder step pads on my C30 stern ladder. The pads are plastic, sold by Catalina Direct. They suggest drilling & riveting to the ladder rungs. My concern is drilling into the hard stainless steel tubing of the ladder. Does anyone have any experience or suggestions. I'm afraid I will burn out a lot of drill$ in the process.
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its not fun
I did the same project on my C-30 SS ladder. make sure you have a drill press and a good punch.
I did the same project on my C-30 SS ladder. make sure you have a drill press and a good punch.
just did a few projects
That required drilling through stainless......Research and buy the best bit for the job....there are colbolt and titainium bits that will do....I found using cutting oil to keep the bit lubed and cool helped alot...True value has that.
That required drilling through stainless......Research and buy the best bit for the job....there are colbolt and titainium bits that will do....I found using cutting oil to keep the bit lubed and cool helped alot...True value has that.
Get a hard drill bit
When drilling stainless steel a conventional Highspeed drill bit won't work. All you will end up doing is work hardening the stainless steel and burning out your drill bit. Get a couple of Cobalt bits in the diameter recommended, they will make the task a lot easier. Mark your hole positions with a center punch so that the bit doesn't slide around as you start the hole. Use stainless steel rivets, and be sure your rivet gun has enough strength to pull them...
When drilling stainless steel a conventional Highspeed drill bit won't work. All you will end up doing is work hardening the stainless steel and burning out your drill bit. Get a couple of Cobalt bits in the diameter recommended, they will make the task a lot easier. Mark your hole positions with a center punch so that the bit doesn't slide around as you start the hole. Use stainless steel rivets, and be sure your rivet gun has enough strength to pull them...
Here's what works for me
I start drilling in a burst with a lot of pressure to get a bite into the SS. After it starts cutting keep steady pressure at a low to medium speed. Make sure it continues to cut. If it stops cutting, you will start to harden the SS and ruin the bit. I have never had a problem using this method to drill stainless tubing. You do not need a drill press for tubing. Flat stock of any significant thickness is another story. I would also suggest buiding some type of template/guide. BTW, once you harden the SS, you're finished. Take it to a machine shop. Tim R.
I start drilling in a burst with a lot of pressure to get a bite into the SS. After it starts cutting keep steady pressure at a low to medium speed. Make sure it continues to cut. If it stops cutting, you will start to harden the SS and ruin the bit. I have never had a problem using this method to drill stainless tubing. You do not need a drill press for tubing. Flat stock of any significant thickness is another story. I would also suggest buiding some type of template/guide. BTW, once you harden the SS, you're finished. Take it to a machine shop. Tim R.
My way
Use a 135 degree split point cobalt bit and drill with a slow speed but high pressure. Don’t let the bit slip but keep it cutting. If it slips it will heat up and destroy the bit and harden the stainless. I use a block of wood as the guide. I drill a hole with a drill press the size of the stainless tube and drill a hole at right angle to that for the bit. I then split the guide on the bandsaw. I clamp that on the tube so all the holes are centered without risk of slipping and scaring the tube. The hole will come out on the center of the opposite side this way. Polish the hole afterwards so you get the metal chips out to prevent rust. If you can, dip the parts in battery acid and run a dc current from the stainless to an anode (or is it a cathode?) to passavate and polish the work. All the best, Robert Gainer
Use a 135 degree split point cobalt bit and drill with a slow speed but high pressure. Don’t let the bit slip but keep it cutting. If it slips it will heat up and destroy the bit and harden the stainless. I use a block of wood as the guide. I drill a hole with a drill press the size of the stainless tube and drill a hole at right angle to that for the bit. I then split the guide on the bandsaw. I clamp that on the tube so all the holes are centered without risk of slipping and scaring the tube. The hole will come out on the center of the opposite side this way. Polish the hole afterwards so you get the metal chips out to prevent rust. If you can, dip the parts in battery acid and run a dc current from the stainless to an anode (or is it a cathode?) to passavate and polish the work. All the best, Robert Gainer
How about tapping?
Instead of rivets and self tapping screws I was thinking of buying a #6 or #8 tap and tapping the holes. What do you think? In addition, should I drill a pilot hole first and follow up with additional drills? And thanks all for the drilling advice so far, sounds good. Great idea Robert, thanks!
Instead of rivets and self tapping screws I was thinking of buying a #6 or #8 tap and tapping the holes. What do you think? In addition, should I drill a pilot hole first and follow up with additional drills? And thanks all for the drilling advice so far, sounds good. Great idea Robert, thanks!
Axel, If you don't have experience tapping
stainless steel then this isn't the place to start. I had to drill and tap six 6-32 holes in 1/4 stainless last spring. It took well over an hour and I know what I am doing. In brass or aluminum it would have taken 20 minutes.
stainless steel then this isn't the place to start. I had to drill and tap six 6-32 holes in 1/4 stainless last spring. It took well over an hour and I know what I am doing. In brass or aluminum it would have taken 20 minutes.
Buy a scrap of SS tubing
from your local boatyard and use that to perfect your technique. Do not tap. Throughbolt the teak. The back and forth rocking force on the step will eventually work a tapped screw loose and ruin the threads. Drill all the way through, clean it up and bolt all the way through. Tim
from your local boatyard and use that to perfect your technique. Do not tap. Throughbolt the teak. The back and forth rocking force on the step will eventually work a tapped screw loose and ruin the threads. Drill all the way through, clean it up and bolt all the way through. Tim
Solesave
They're called SoleSavers and they have them on this site. They secure around the tubing, no drilling. Works great, less filling.
They're called SoleSavers and they have them on this site. They secure around the tubing, no drilling. Works great, less filling.
Use a small bit first
It is generally accepted practice to 1) punch 2) drill a small <<1/8" hole 3) drill a larger hole 4) drill the final size hole The problem with "drilling it all at once" is the center of the drill is not the part that does the cutting the outer edge is. By using a series of drills you get rid of the "center" with the first smallest drill and then the rest is just a cutting action. IMHO SS is not that hard to cut. Tough and chewy but not hard. If you really want a challenge try monel.
It is generally accepted practice to 1) punch 2) drill a small <<1/8" hole 3) drill a larger hole 4) drill the final size hole The problem with "drilling it all at once" is the center of the drill is not the part that does the cutting the outer edge is. By using a series of drills you get rid of the "center" with the first smallest drill and then the rest is just a cutting action. IMHO SS is not that hard to cut. Tough and chewy but not hard. If you really want a challenge try monel.
One of the tricks the metal workers use is
they use evaporated milk instead of cutting oil. It sounds weird but I have drilled more than 20 holes in thick stainless with one cobalt bit and it is still like new. I drizzle it as I drill with a syringe. No smoke or oily mess. Try it.
they use evaporated milk instead of cutting oil. It sounds weird but I have drilled more than 20 holes in thick stainless with one cobalt bit and it is still like new. I drizzle it as I drill with a syringe. No smoke or oily mess. Try it.
I learned this from a journeyman steamfitter
When drilling SS: Drill slow and lube the bit with spit. SS Is one of the metals you don't use an oil. I have found this to be true. It takes longer with oil.
When drilling SS: Drill slow and lube the bit with spit. SS Is one of the metals you don't use an oil. I have found this to be true. It takes longer with oil.
SS is a 'work hardening' material. As it heats up the metal near the drill bit becomes tempered and harder. Water (in the form of spit, milk, whatever) keeps the work cool and therefore it doesn't work harden. Also the suggestion of starting small and moving up in drill size keeps the heat and the amount of material to be removed at a minimum making for easier drilling.
I love the methods that have been used
almost like alchemy. When I supervised the spinnerette shop at Firestone we drilled 1/8 inch holes 1 7/8 inches deep in 316 stainless steel and we used a water reduced cutting oil to keep the drill cool and to lubricate the cut. There were 204 holes per spinnerette and a broken drill was a major job to remove so we took some extraordinary steps to avoid breakage. If the drill is allowed to spin without cutting, the surface of the SS will work harden BUT agressive feeding will get you past the hard spot but you must back off before the drill is loaded with chips.
almost like alchemy. When I supervised the spinnerette shop at Firestone we drilled 1/8 inch holes 1 7/8 inches deep in 316 stainless steel and we used a water reduced cutting oil to keep the drill cool and to lubricate the cut. There were 204 holes per spinnerette and a broken drill was a major job to remove so we took some extraordinary steps to avoid breakage. If the drill is allowed to spin without cutting, the surface of the SS will work harden BUT agressive feeding will get you past the hard spot but you must back off before the drill is loaded with chips.
Cobalt drills
I know, I know, its been mentioned several times, but I have to add my emphasis. Our inept Hunter dealer broke dozens of steel drill bits installing our bimini. Not til later did I find out the secret of cobalt drills. They make all the difference and will stand up to SS all day long.
I know, I know, its been mentioned several times, but I have to add my emphasis. Our inept Hunter dealer broke dozens of steel drill bits installing our bimini. Not til later did I find out the secret of cobalt drills. They make all the difference and will stand up to SS all day long.
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