Question regarding drilling SS guard

[BobM]

Any advice on how to drill both Navpod mounting holes and a hole for chasing wires down a 1" guard? Tool suggestions? I used to watch the guys on OCC make choppers and they used one of those conical multi-size bits to ream holes out. Is that the ticket? Center punch first I assume. Suggested bit material? Any other wisdom related to this job is also appreciated. It is a double bend guard and only one inch, but I don't have much in the way of wires to run, just a chartplotter than doesn't need any funky connectors passed through the guard and my stereos wired remote, so I am not anticipating too much trouble. I just figured to drill my chase hole, tie a string to a nut and drop it through.

Thanks in advance for the help,

Bob

 

[pvanv]

Sounds like you've got it right. I like to use the sharpest bit I have, HSS or better (titanium is fine). I also like to use a 1/2" tapered reamer (available at the toolroom of home improvement places) to finish off the hole. A UV-resistant neoprene grommet at the hole would be nice. You may end up using a stiff "fish" wire instead of the string-and-nut to chase the cable run.

 

[Chuck Creel]

Right on track. Center punch for shure with carbon or SS high speed bits.
Also might want to lube the wiires as you pull them through with a fish tape.

 

[seadaddler]

Just did it

I just had to add a cable in my already crowded SS navpod pole,I already had a half dozen cables going to my C-80,heavy radar,chartplotter,auto,and other instruments.
My post was so tight that I tried drilling the other pole only to find out it was a dead end and unusable but did drill a very nice hole with a sharp small size starter drill,the drilling went fine with a very easy job,the trick is go slow and starting out small and work ing your way up,using all already mentioned reamers.
I had to use a electrical fish wire with lube,like I said mine was already full of other cables and a long run down and under the helm floor which sounds like yours will be easier than mine.
It's not hard with good drills and go slow not to get the metal too hot or break a drill and you will be fine.
Nick

 

[BobM]

Thanks! That was fast. I only posted this morning. Hmmm...sounds like it might also be useful to leave a line going through the pedestal just in case I need to run something in the future.

 

[tommays]

The hole reamers dont really work that well on SS compared to a good drill bit

With most SS drilling i like a small split point like the black & decker bullet drills to stop any walking from the center punch you want to go up in size in about 2 steps at most

If you try and go up in really small steps the drills tend to grab and jam

You also need to use a dremmel to debur the inside edges of the hole as it will have some razor sharp edges


I also want to caution you the better drills like cobalt tend to break in 3 pieces if you jam them

1. one part in the hole
2. one part in the drill
3. one part boucing off you saftey glasses

 

[sailingdog]

One other point... you will want to use a slow drill. If you use too high a speed, the drill bit may work harden the stainless steel and make it much more difficult to cut.

 

[higgs]

Go slow enough to chip away the ss and you won't have a problem with hardening.

 

[Tim R.]

This is what has always worked for me.

Start off will a good sharp bit, add a little oil and drill slowly. Initally I use a lot of pressure to get the bit to "bite". Once you get into the metal it will go pretty smoothly. Don't let the bit get hot and use oil if you need. If you start to see smoke, stop.

 

[SamLust]

When I make a hole of the sort you're doing I do my finish smothing with a Dremel type hand grinder. They have a nice little carbide bit that works very well. Just a few minutes and you'lll get rid of all the jaggies that love to eat wire.

 

[Maine Sail]

You've

You've received good advice thus far. I'll only add the following.

A) For the big hole that the wires come out of use a Lennox hole saw or other high quality hole saw. This will make a nice cut and give you a hole big enough for the wires but do clean the edges up with a Dremel. If my memory serves me correctly I think I use a 3/4" or 7/8" hole saw for this.

B) One trick I use when drilling stainless is to use a center punch then a pull trigger, let stop, pull trigger let stop, pull trigger let stop method as it keeps the work cooler and rarely leads to work hardening. You should always try and use a good cutting oil too.

C) For the NavPod fastening screws use the proper sized drill for the tap you will be using.

Remember good quality bits & hole saw, go slow or use the trigger/pause method, use cuting oil, and clean up the edges with a Dremel to prevent cutting the wires..

 

[Ron20324]

If you're hesitant to smack your guard with a hammer and punch, put about five wraps of tape around the guard. Mark the hole location. The tape will keep the bit from wandering.

 

[Bob S]

If you have a small drill press it works a lot better. I bought a new angled pedestal guard that I put in a drill press and drilled using a C clamp and some wood pieces to hold the guard from moving. I think the hole saw idea from Mainesail would be the easiest. Definitely use oil, any kind to keep the cutting edges lubricated and go slow. It will be very difficult using a hand drill.

 

[Maine Sail]

This is one I did

This is one I did back in 2000..

 

[Bob S]

Mainsail, that looks like a Raymarine set up. I like the terminal board, great idea. I soldered and used heat shrinkable tubing. The connectors where too big to snake up the post. BobM, I did use a lube to snake the wires. I bought at an electrical supply house.

 

[Maine Sail]

Mainsail, that looks like a Raymarine set up.

Yes it was an old SL-72 series plotter/radar...

 

[BobM]

Thanks guys! To stop it from wandering I was thinking to make a jig out of scrap wood. Take a piece, drill a 1" hole through it, cut it half then run a couple of wood screws through it to clamp it in place. I won't spare the lubricant. Good idea to make the hole oversize now, even though I don't need a big hole for the wires I need to run at the moment. It will be much easier to do now than at a later date when the guard is attached to the boat. Perhaps I'll do both sides, just in case.