Chainplate Replacement

[sabray]

I m replacing the intermidiate and upper chainplates on my Peterson. Any help here appreciated. I did this years ago on a ketch and drilled the plate stock on a good drill press. I still went through I recall tons of bits Kobalt tipped etc.. Drilled small hole and then bigger ones. Im dreading doing this again but alas Im a miser and Challenge myself with projects. I like doing things self suffient and all. But may consider having a machine shop do it this time. Any reccomendations. Im on the chesapeake bay but could ship the templates. Also does eloctroplate polishing help with crevice crack corrosion or is it aesthetic. The exposed section of the chain plates I removed are polished but below deck they look raw. Your exeriences As I go forward.
Thanks

[pressuredrop]

dont know if your handy with fiberglass, but i have all but convinced myself that when mine are up for replacement i will be making fiberglass ones. part of the glutton for punishment thing, i guess

how i envision doing this (mine are exterior mounted s.s. currently), i will use the old ones for patterns and cut my glass in the shape and make a form of the appromixate curve (very slight) and then lay up enough fiberglass for each one to get them ~1/2" thick. then trim em, throughbolt them with epoxy putty and lots of fiberglass, and glass them on and never worry about replacing them again

wont get around to this project for a year or so but ill keep you posted when i do

[Martinini]

IMO polished is better if you can. Skip the pilot hole and use a Titanium bit the size you need. I just drilled 1/8" 316 stainless, 40 holes and destroyed 21 standard bits on 18 holes. Then I spent the extra dollar on the Titanium bits and finished the job with two bits. If your using a hand drill make sure you keep it as close to 90 degrees as possible. If you have a drill press even better. I also was surprised to find that using oil to cool the bit and steel made the bits more brittle and the stainless harder.

[btrayfors]

sabray,

Take it to Aric Euler at Chesapeake Marine Engineering at Rockhold Creek Marina in Deale, MD. One of the best metal-working shops on the Bay.

Bill

[Martinini]

Pressuredrop I have fiberglass chainplates on my boat, done professionally before I purchased her. mine are about a 1/4" thick and since I have a Princess they go through the deck. If you make yours 1/2" thick that should give you plenty of overkill value. Also have you found these guys yet Allied Seawind II Home Page

[pdxsailordiver]

The key to drilling stainless is speed and feed. Off the top of my head I would say 900 -1000 RPM and a good coolant for the bit. You do not need special bits just a good variable speed drill press.

[Martinini]

Originally Posted by pdxsailordiver

The key to drilling stainless is speed and feed. Off the top of my head I would say 900 -1000 RPM and a good coolant for the bit. You do not need special bits just a good variable speed drill press.

My experience of the last two weeks has taught me otherwise. I believed as you --- no special bit required until I went through so many good quality non Titanium bits in the Marinas drill press. Quality stainless is hard stuff. Some of those bits went dull in under 20 seconds----no kidding. A good tool = a good job.

[sabray]

What is the correct angle for the drill tip.

[Martinini]

135 degrees I believe.

[sailvayu]

The trick is water. Keep a steady stream of water on the bit to keep it cool. Never let it get hot. Oil burns off too fast. You will be able to do all the chain plates with 1 bit it might need resharpening a couple of times but you will only need the one. I have done this and I know it works. You can also cut stainless with a saber saw keeping a stream of water on it. Don't believe me try a test piece you will be amazed it cuts and drills just like carbon steel. Slower speeds help too keep the heat down it is all in not letting the cutting tip get hot at all.

Good luck

[pressuredrop]

Martinini - do you have any pictures of your chain plates you can post? i remember seeing some fiberglass ones on a modern cat in some other post

[pdxsailordiver]

Originally Posted by Martinini

My experience of the last two weeks has taught me otherwise. I believed as you --- no special bit required until I went through so many good quality non Titanium bits in the Marinas drill press. Quality stainless is hard stuff. Some of those bits went dull in under 20 seconds----no kidding. A good tool = a good job.

If you were in the Portland area I would Have you come over and drill the holes for you. Your Marina drill press you used runs to fast. When I made a turning plate for under my mast for blocks for run lines to cockpit. (14) 1" holes. in 5/16 316L plate all with out pilot holes. Drill press RPM 150. Standoff plates for winches on mast 1/4" 316L (6) 5/16 holes each plate(2 plates) RPM 900. Plate for mooring cleat and inner stay 1/2" 316L, All were drilled bent and polished by me. Go to FACEBOOK look up Maria Victoria (Cascade 42)look at photos.
I have an adjustable gear drive drill press (think machine shop) and a craftsman that I replaced the motor with a 208v 3 phase motor and a VFD with a 110v input so I can plug it in a standard outlet. so I can control speed. Again it is all about speed and feed.

[SabreKai]

I was taught by an old English millwrigh to resharpen my drills, 120 degrees for MS and to change the angle to 140 for drilling stainless. High pressure on the drill and a lower speed will get you done.

Learn to resharpen your drills, it will save you a small fortune. The only time I toss one now is if I break it off too short to be useful.

Sabre

[delmarrey]

Originally Posted by sailvayu

The trick is water. Keep a steady stream of water on the bit to keep it cool. Never let it get hot. Oil burns off too fast. You will be able to do all the chain plates with 1 bit it might need resharpening a couple of times but you will only need the one. I have done this and I know it works. You can also cut stainless with a saber saw keeping a stream of water on it. Don't believe me try a test piece you will be amazed it cuts and drills just like carbon steel. Slower speeds help too keep the heat down it is all in not letting the cutting tip get hot at all.

Good luck

Finally, someone got it right. As a Machinist of 45+ years I can tell you it's not a fun drilling SS, especially the 303/304's. I dread 347 and some other aircraft stuff.

But any way, colbalt drill bits are best. Carbide is too expensive and has to be total controlled at hi speed to keep from chipping them.

The secret is a slow speed and continuos pressure until it's about to break thru, then ease off for the final pass. The object is to not get the metal hot. It's called work hardening. The heat causes the carbon to transfer from the bit to the metal making the metal as hard or harder then the bit itself. SS is one of the worse metals for this due to it's bond. It's a catch 22. The hotter it get the harder it gets, the harder it gets the hotter it gets.

I use what is called a spray mist, a mixture of a coolant and a jet of air. Submersed in water is OK too just not easy to control on drill presses and knee mills.

The drill angle on colbalt drills is 135º with a split point that can not be resharpened properly/accurately by hand w/o diamond wheels.

If you can not see the flutes of the drill plainly as it turns, then it's going too fast. If it starts to squeal then it's getting dull and you need to get another drill and run it even slower.

But remember "continuos pressure" to the last little bit. When the drill breaks thru it creates more heat then during actual drilling.

Pilot holes are recommended if one can not put enough pressure to keep a chip flowing. Trying to hand drill anything over 3/8" dia., I'd recommend a pilot drill of 1/8". A 1/2" drill by hand I'd pilot with a 1/4" drill bit. Trying to drill anything over 1/2" could be hard on the wrist.

A 3/4" by hand I'd pilot it twice. And even then could be rough if it grabs.

Remember keep the cool chips flowing.

[sabray]

I can re sharpen a bit. like suggested earlier do you make a single bore. These holes will be 1/2" and the turnbuckle hole is 5/8". Im thinking Ill drill in a tub of water I have a very good radial drill press. So slow speed, saturated with water and drill to size one time.
Thanks for all the advice. Why not Bronze? Thats a good question I can't find bar stock Stainless is cheap and installing it properly should mitigate stress crack corrosion for my lifetime.