Another trick is to drill a smaller diameter pilot hole first. Especially if the final hole will be 1/4" or larger. If there is stress in the gelcoat, the pilot hole will relieve some before the final cut is made. Also the final drill size will be in contact with less material which reduces odds of the bit 'grabbing' too hard and chipping or splintering material at edge of hole. Also, always chamfer the edge of the finished size hole on the gelcoat side. This makes cracking/crazing of the gelcoat when you tighten the fasteners considerably less likely. It also makes a space for the bedding to squoosh (that's a technical term) into and form a good seal. A regular 'universal' countersink tool in your power drill works fine. cheers, John S. On 08/17/2018 03:42 PM, Lawrence Winiarski via montgomery_boats wrote:
One trick I learned: I know it sounds counter intuitive, but if you run the drill in reverse it will be less likely to chip the gelcoat. Justtakes (alot) longer to drill that way as it's more "wearing" than "cutting"
From: doug <doug9326@gmail.com> To: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Sent: Thursday, August 16, 2018 3:58 PM Subject: M_Boats: new ladder & drilling holes in transom
I am about ready to drill some holes in my transom of my M-15. Yes, it scares me but it has to be done. I am adding a flip up ladder from West Marine to the transom. In order to beef up the transom I have had made for me two backing plates. One goes on the back of the transom and the other goes on the inside of the transom. Each has holes drilled in them to line up with the corresponding holes in the other plate. I will also be glueing the 12 gauge plates to the boat as well as having the 3” bolts attaching both plates to one another. Before I drill these holes, six of them, for support and to hold the plates to the transom from both sides, I thought it might be prudent to run this by whoever happens to see this post. I have never drilled holes in any sailboat I have owned and that is a lot of them. I am being careful to line up the holes on both plates so I don’t miss the holes on either. They have to line up perfectly to run the bolts through. This will happen after they are both glued to the transom with 5200. There is no turning back once that starts. So if you have any ideas for me, I am open to this and excited to get this project done. My M-15 looks great even though its a 1980 version. I want to keep it that way.
Thanks
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