Clipper's Vera Cruise Build

Clipper's Vera Cruise Build

Wednesday, February 15, 2017

Hatch Milling

I was originally going to wait until I had more of the hatch completed before posting, but things being what they are, I was delayed by a week of sickness and then a shifting of life's priorities.  As it may be some time before I can return to the hatch, I have elected to post what I have.

My friend Skip offered to help mill the hatch some time back. He has proper routing tools which made this job easier than anything I could have done at my house. He is also more experienced at wood working than I am, which insured a more likely successful outcome in this endeavor.

As readers will remember, I had epoxied together 8 pieces of mahogany into an octagon shape approximately 22 inches in diameter. The intent was to mill out the center and outer edge to get a round deck hatch to replace the plan's rectangular hatch. The hatch would eventually receive a smoked polycarbonate insert in the center. Additionally, the hatch would fit down over a deck ring that I had previously made from strips of mahogany glued edgewise into a circular shape.

The first thing that needed to be accomplished was for the octagon to be attached to a sacrificial plywood board and a center point established. This center point would be where a circle cutting router attachment would be mounted. The octagon was attached upside down to the plywood. We accomplished this by using double backed tape to hold the octagon to the plywood and then stabilizing it by attaching blocks of wood to the plywood around the perimeter of the octagon.

Additional wood was placed in the in the center before establishing the center point. This wood would elevate the circle jig to the same height as the deck hatch.

Then, after setting the router jig to the correct dimension, we routed out the inside of the hatch.

Next, we needed to mill a rabbet edge on the inside of the circle. This would be the eventual landing place for the deck ring. Since the deck ring was made from rectangular pieces glued together on the edges around a circular form, it was not a perfect circle. Close, but still not perfect. This required that the rabbet edge be large enough to allow the entire ring to fit. The ring was placed on the hatch and rotated until we found the best fit. From that we marked the extent of the diameter that was needed and set the router jig appropriately.

The depth of the cut was set to 1/4" as the deck hatch is only 1 inch thick. The cut was then made.

Next, we wanted to cut the exterior of the hatch. This required that the stabilizing blocks be moved to the inside of the hatch. The leftover wood from the inside cut was conveniently used to make placement of these blocks easier. The router jig was adjusted to the outer dimension and the outer edge was cut. During this process the router bit broke and my heart skipped a beat. But all was well, and after replacing the bit and resetting the depth, we continued on and completed the cut.

At this point the hatch was removed from the plywood. We had intended to cut a rabbet on the inside edge on the opposite side (the topside) to receive the smoked polycarbonate plastic. I am planning on purchasing 3/16" thick material for this, but since we didn't have it available, and because I wanted this cut to be exact, we elected to not perform this step. I will do this in the future when I have the plastic.

The remaining task was to bevel the topside to give the hatch a more pleasing profile. It would be beveled 10 degrees down and approximately 320 degrees around the hatch with the remaining  40 degrees left square in profile. This area is where the deck hinge will eventually be mounted.

But how to cut this bevel. At first we considered the router, but realized quickly that it wouldn't work. I had considered, prior to Skip's offer of help, using my table saw to cut the bevel by fashioning a rotating jig and holding the hatch at an angle to the rotating blade.

Skip suggested we do something similar but angle the blade instead. After scratching our heads for awhile we came up with a jig that rotated the hatch vertically on a  fence with the blade angled outwards 10 degrees. In order to make this work, we had to start the blade spinning and then gradually raise it up in small increments with the hatch in place. We would then rotate the part in the jig to cut the bevel. In order to stop cutting before we reached the area that was not to be beveled, marks were drawn on the hatch which we would stop at as we rotated the hatch.

It was a bit dangerous and potentially could have ruined the part, but by taking our time and coordinating our efforts, we got through it with no damage to us or the part. The bevel had slight steps from where we raised the blade each time, but these are small enough that sanding will take them out. Where the bevel transitions into the non beveled area, we had to stop short on both sides of that area, so it will be necessary to manually clean the remaining wood out and clean up the bevel. But this is a small amount of work and the bevel turned out good. There will also be some additional edge rounding and cleanup required.

The plan is to return to this sometime down the road when I get closer to needing it. I want to figure out a way to create a slight dome on the smoked polycarbonate insert, rather than have it go straight across the top of the hatch. I have some ideas on this that I am going to look into at that time.

However, I just had to see what this was going to look like on the boat. And since I still had to finish assembling the center deck structure, I could do that and get a look see at the same time.

The only assembly work done on the deck structure was to epoxy the cross brace behind the hatch ring into place between the two fore and aft members. The hatch ring will not be installed until after the deck is in place in order to facilitate cutting the opening in the deck for the ring to pass through. The deck structure will also be left off for now while I continue work in the forward area of the boat.

One other accomplishment during this time was to work out the design for the bow compartment bulkhead hatch door and other decorations. These were mocked up and various ideas tried out. In order to do this work properly, I determined that I am going to need to do some upgrades to my table saw and acquire a router table.

With space in my garage being at a premium, the time had come to make some changes in the layout of the garage. The plan is to replace a shelf with a rolling cart that doubles as a mixing station for epoxy. The shelf is going away and the tool boxes will be rearranged together at the right of the work bench. Other items in the garage are going into storage. The workbench will become the place that I set any new power tools I need.

While this arrangement is not ideal, given that I hope to move sometime in the next six months and the fact that I have alternatives to the bench that I can use, I feel this is an acceptable solution. It does require, however, that I build the movable mixing cart, which I have started on.

This cart construction,  the moving of items to storage, and making upgrades to the table saw will require some time. So boat construction will be suspended for a little while. Hopefully not too long, and I may still sneak in a little work here and there.

Until next time, take care.

Click Here To Comment:

Post a Comment

Feel free to comment on what you've read here. I only ask that you keep it civil.