Laminating a stem

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Tom

Laminating a stem

Post by Tom »

I just received my plans for the jolly roger. In the instructions it says the stem is a 3" piece of solid core wood in 3 pieces bolted together w/carriage bolts countersunk so as not to interferre with fairing. Then laminated with 1/2 in ply on each side. Are the bolts supposed to go veritcally throught the pieces. How would you cut the joints to bolt them together? It's 11 inches wide at some points. Would't it just be easier to make the whole stem out of plywood laminated to the desired thickness?
Any explanation or thoughts would be appreciated. Thanks

Guest

Post by Guest »

You mentioned you read this from the instructions. I believe the instructions are different from the plans. What does the 'plans' indicate?

Guest

What the plans say

Post by Guest »

Thanks for the response. Sadly the plans dont make any mention of it. The pattern page just has the outline for the stem and breasthooks. No dimensions or materials are mentioned. I checked all the other pages and the stem is only mentioned again as to notching it for the keel. And one small detail drawing of attaching the top breasthook. I guess I will have to call glen l and get a answer. Just a little discouraged at being stumped so early into this. It is the first piece I need to build.

bronk
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Post by bronk »

Don't be discouraged asking for help for the ends.

The ends are the hardest part. I did BY FAR the most head scratching on the transom and then the stem to batten transitions.

While it may be counter intuitive, start in the middle. The middle frames are easy. Build your experience there and then work outwards to the ends.

I started at the transom (mistake). It was a very difficult 3D multti-stage glue up. I had not yet discoverd he lubriciousness of wet epoxy or many other little items. Conversely, the nice flat frames were much easier and I could add to my technique and knowledge without getting into trouble.

While Glen and Barry usiually pretty quick with answers, don't wait. Start with the "easy stuff" and don't worry about building frames out of order.

The point of keeping metal clear of where you will fair must not be underestimated. Remember, you edge tools will seek out any buried piece of metal. You will carve away a fairly large chunk of the stem when fairing. It is very important to bury the fasteners well (or remove them after the eposxy cures), lest they haunt you later.
Mark Bronkalla
www.bronkalla.com - 50 mph furniture

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kens
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Post by kens »

Ditto on Bronk's entry. Do the 'easy stuff' and get a feel for your tools, bench, workshop as it applies to all the layups your gonna do. Get a system in place for your epoxy mixing station (mix cups, sticks, materiel, etc.) and work those things out on the flat frames. Then, after you build up some parts you go after the hard curvy, compound stuff.
I done this couple times already, and the transom & stem is still a booger.

Guest

Thanks

Post by Guest »

Thanks for the encouragemeant and good advice. I think I will do just that and start on the easy frames and get a feel for it. Maybe by the time I get to the stem again I will have figured out what I need to know and if not then I will call for help. Thanks again!!!!!!!!!

BobL
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Location: Malaysia

Post by BobL »

Hi Tom,

I am about to finish my Jack Tar stem. Certain portions of my patterns are common to Jolly Rogers, as it says in the pattern. The instructions I have got suggest that I use two 1.5" stock laminated together and two 3/8" plywood on both sides. Alternatively, use 4 layers of 3/4" plywood with staggering butt joints. I am using the later method.

The problem of not having a bandsaw for the job is that the layers do not fit exactly since I have been cutting the plywoods layer by layer. I intend to use a belt sander to even them up.
Regards,
Bob

If your boss is driving you nuts, build a boat.
Growing older is mandatory, getting wiser is optional.

Barry
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Post by Barry »

BobL's comments are correct. And the hulls are based on the same frames.
The stem is fairly simple. Four laminations cut to the stem pattern, stacked on top of each other and glued together. Because of the wide piece that would be required to cut from a single piece, it is usually pieced.

You can use all plywood, as long as you build to the same total thickness.

You might want to keep BobL's email address since you are essentially working on the same project. Hope you are both in the Project Registry...

RonW
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Location: Cincinnati Ohio

Post by RonW »

Additional suggestion. On a stem I put together out of 4 pieces of 3/4, I glued and screwed 2 pieces of 3/4 together and then cut a 45 degree angle on it, then did the other 2 pieces with a 45 degree pre cut bevel as well, ( you have a left and right) then glued the 2 sides together and you have a perfectly and easily prebeveled stem at 45 degrees, which will save a lot of work.

BobL
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Location: Malaysia

Pre cut bevel

Post by BobL »

Hi Ron,

Your method definately saves a lot of fairing work. As the bevel is varying continuously along the stem, is 45 degree the smallest angle? .

What boat are you building?
Regards,
Bob

If your boss is driving you nuts, build a boat.
Growing older is mandatory, getting wiser is optional.

RonW
Posts: 111
Joined: Wed Nov 12, 2003 4:55 pm
Location: Cincinnati Ohio

Post by RonW »

Hi BobL -
Check your prints, most of them say prebevel to ( whatever) to save a lot of fairing. You can bevel it what you want, say 40-35-or 30, it just helps get rid of a lot of wood quickly. Instead of using a belt sander, get yourself a makita 7inch disc sander with 16 grit sanding discs, it will eat up some wood. It is also a lot lighter then a belt sander and much more controllable, you will also be surprise how delicately you can touch sand just because it is more controllable. Of course this is just for roughing out and you could never finish sand with it, there you need a palm sander.
The jack tar is a big boat, you have your work cut out, Good Luck...

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