Drilling old Chainplates

[Time2Go]

Hi Friends,
We are replacing chainplates on a Irwin 44.
The original construction is similar to IP’s and the plates are glassed in.
Our plan is to go to external plates, drilling thru the old ones,
leaving them in place and then adding either SS backing plates
or really big SS washers.
We are going to do this one at a time with the stick up.
Does anybody know of any videos of this procedure?
Like to have a look see before we start.
Cheers
Neil

[coopec43]

Originally Posted by Time2Go

Hi Friends,
We are replacing chainplates on a Irwin 44.
The original construction is similar to IP’s and the plates are glassed in.
Our plan is to go to external plates, drilling thru the old ones,
leaving them in place and then adding either SS backing plates
or really big SS washers.
We are going to do this one at a time with the stick up.
Does anybody know of any videos of this procedure?
Like to have a look see before we start.
Cheers
Neil

You will have a real job drilling through your original chain plates with an ordinary electric drill.

You need a slow drill and lots of pressure. Can you make up a jig so you can apply the pressure? (Alright if you have a bench drill!)


https://www.sailmagazine.com/diy/kno...tainless-steel

[fourlyons]

Don't forget the cutting oil, the bits last longer, cut more easily, and don't need as much pressure. Also, I'd spring for cobalt bits.

[gonesail]

a guy at my marina did his chainplates. he used a single piece of bronze bar that was easy to cut and drill. he then polished it with a buffing wheel and the results were outstanding.

[Ballsnall]

Drill a pilot hole first and easy peasy with a hand drill.

[coopec43]

If the chain plate is chest high I doubt you'll be able to apply sufficient pressure. I've always used HSS drills- no problem.

If you drill without removing metal you will work harden the SS and then you are in real trouble. I had to use a sharpened masonry bit with timber across the back of the drill to increase the pressure.

https://www.youtube.com/watch?v=205cQSUnimE

[Madehn]

Drilling through existing chain plates that are encased in fiberglass is going to be a real B&!(#. Drill real real slow. You should be able to see the bit turning very low rpm. LOTS of pressure It is going to go thru a lot of bits and make a mess. Also going to generate lots of heat. Enough to burn up that encasing fiberglass is not REAL careful. If you are just drilling thru existing holes then that is a different story. For that drill the fiberglass and mark one bolt hole in your new plate then mount new plate on outside and mark holes for rest of bolts on new plate. Take off new plate and take it to shop with drill press to do the rest. Takes time but will work. Good luck

[Madehn]

Forgot. Cutting oil and cobalt bits are necessities. Buy extra bits and go slow Speed and heat are your enemies here. Lowest setting on my drill press is at least twice as fast to do this right.

[wingssail]

Originally Posted by Time2Go

Hi Friends,
We are replacing chainplates on a Irwin 44.
The original construction is similar to IP’s and the plates are glassed in.
Our plan is to go to external plates, drilling thru the old ones,
leaving them in place and then adding either SS backing plates
or really big SS washers.
We are going to do this one at a time with the stick up.
Does anybody know of any videos of this procedure?
Like to have a look see before we start.
Cheers
Neil

Take the chainplate off and take it to a machine shop. (if you want the holes to be in the exact place, then punch the chainplate before removal)