Rolling Bevel question

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Patricks Dad
Posts: 1476
Joined: Wed Oct 13, 2004 1:11 pm
Location: Warrenville, Illinois

Rolling Bevel question

Post by Patricks Dad »

My son and I are building a Redbird and are about 3 strips away from covering the inner stem. We have been shaping the rolling bevel as we go. Last night we started on the final shapping of the inner stem (between Station 8 and 7).

My question deals with the inner stem as it approaches or butts into Station 7. The Inner Stem is 3/4" thick but sticks up ABOVE station 7 by maybe 1/8". (not sure if this is per design or the result of an error in aligning station 7 with the Stem Mold).

In order for the rolling bevel to match station 7 exactly it would have to be cut such that it comes to a point rather than maintain the 1/8" flat surface that has been maintained across the entire length of the inner stem (Station 7 is pointed on the top - it doesn't have a 1/8" flat top).

Should we:

a). Simply continue cutting the inner stem to match the Station 7 shape and lay our strips down. If so, how do you know how to cut the path for the Outer Stem (I thought we would just cut down through the stripping until we reached the inner stem and stop.

b). Continue cutting the inner stem to match station 7 but then flatten the top to create a new 1/8" flat top to use as the base for the Outer stem. (this would require that the outer stem be bent further than planned to match the new inner stem shape.

c). Shape the inner stem to match the angle of Sation 7 but leave it high such that the original 1/8" flat surface is maintained and lay the stripping on the Inner stem but off/above the station 7 mold for the last couple boards.

d). Something else I haven't thought of?


I'd appreciate your thoughts. I hope the above is clear enough to understand (I wish I could draw a picture)....

I'd also be happy to discuss if anyone would like to give me a call (847) 632-5563

Thanks!
Randy Pfeifer
(847) 341-0618
Randy.Pfeifer1@gmail.com
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Glen Smith
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Joined: Sat May 08, 2004 9:08 am
Location: Baie-St-Paul, Quebec, Canada

Post by Glen Smith »

Hi Randy, it seems you have one the following problems: 1)inner stem thicker than 3/4". 2) Mold #7 set too high or wrongly cut. 3) Stem mold set too low or wrongly cut.

I don't see why Ted says to keep a 1/8" flat surface on the inner stem where it meets mold #7. This can't be done without having a protrusion to the sides or having the inner stem lower than mold #7. Between molds #8 & #7 I would shape the inner stem to follow the shape of mold #7. This will mean removing material from the top of your inner stems and this means that the outer stems will no longer mate properly with the inner stems. However, the inner stems should have enough "spring" to them to be able to compensate for the slight difference and thickened epoxy is very good at filling small gaps.
Jeff in Pembroke
Posts: 83
Joined: Wed Jun 30, 2004 8:26 am

Post by Jeff in Pembroke »

Hi Patrick's Dad,

Shape the rolling bevel on the inner stem to exactly match the profile at station 7. As the bevel rolls toward station 8 you will be able to establish the 1/8" wide flat surface. If I recall it is less than 2" from station 7. Put a pencil mark on the strips at the point where the 1/8" flat surface starts. Your outer stem will end at the pencil mark - you want the outer stem to be shorter than the inner. Otherwise, if you cut the mortice for the outer stem right up to station 7 you will end up with a small hole right through the hull. When you start stripping the football, the first couple of strips will attach to the inner stems as well as abutting each other.
Isn't it a great feeling to see the hull take shape?

Jeff
Bernie in Illinois

Post by Bernie in Illinois »

Like Glen said, either your stem, stem mold or station 7 is off. At this juncture, there is little you can do but to follow the contour of station 7. Jeff is absolutely right in his solution, except that the distance between stations 7 and 8 is longer than he remembers. As long as you have inner stem below the outer stem, you cannot break through the hull. If you shorten your outer stem so that it mates to the inner stem with 1/16" or more of contact surface for epoxying, you 're ok. The floor of the mortice for the outer stem is both the top of the inner stem and edge planking.

Good luck,

Bernie
Jeff in Pembroke
Posts: 83
Joined: Wed Jun 30, 2004 8:26 am

Post by Jeff in Pembroke »

Hi Bernie,

I didn't mean to suggest that station 8 is only 2" from station 7 (I hope my last post doesn't read that way). I'm pretty sure it was about 2" from station 7 that I was able to get a flat surface on my rolling bevel and it was about there that my outer stem eventually started. That being said, anyone in my family will tell you my memory is sometimes faulty (although I find that hard to believe :oops: ) so I wouldn't take that 2" dimension as infallibly precise :!:

Cheers,

Jeff
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Patricks Dad
Posts: 1476
Joined: Wed Oct 13, 2004 1:11 pm
Location: Warrenville, Illinois

Post by Patricks Dad »

Guys, This evening I measured the plans for the Redbird. The height of the center of Station 7 is 20 5/8 inches. The height of the Stem mold where it joins with station 7 is 20" With the addition of 3/4" stem on top of the stem mold that leaves the top of the stem resting 1/8" ABOVE the point of Station 7. Measuring our canoe I see that these dimensions are the same as the plan.

It doesn't appear that any of the following are the case:
1)inner stem thicker than 3/4". 2) Mold #7 set too low or wrongly cut. 3) Stem mold set too high or wrongly cut.

It would appear that by design the uncut stem would sit 1/8" above Station 7.

While I'm still curious as to how this is suppose to work, I guess we'll follow Jeff's idea.

Thanks a bunch for all your advice!
Randy Pfeifer
(847) 341-0618
Randy.Pfeifer1@gmail.com
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