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Frame 2 does no match plan

Posted: Sat Feb 16, 2019 10:15 am
by Wawa2c
Hello All

Is it possible the frame full size pattern does not match the noted measurements on the plan?

I am building Flying Saucer with overlap frame joints.

According to noted measurements, centerline to sheer is 34 1/4 and base line to sheer is 38 3/16. But I get from measuring the pattern and from my cut members, centerline to sheer on top member is 33 7/8 and baseline to chine on side member is 35 7/16. See picture of no 2 frame.

Could the paper full size patterns really be off that much?

What should I do? Build to the noted measurements (would cause overlap frames not to align) or set members in alignment (would cause overall dimensions not to match noted measurements)?

Jonathan

Re: Frame 2 does no match plan

Posted: Sat Feb 16, 2019 11:37 am
by billy c
...isn't the chine joint a plated butt joint no overlap?
Billy
Image

Re: Frame 2 does no match plan

Posted: Sat Feb 16, 2019 1:35 pm
by Wawa2c
Hi Billy,

Sorry meant sheer line (looking at it upside down). For construction on this model overlap frames with ply gusset are being used, as per the plan.

Re: Frame 2 does no match plan

Posted: Sat Feb 16, 2019 1:39 pm
by Roberta
Like Billy stated, many of the joints on the plans along the chine line are drawn as but joints with overlapping plywood gussets. There would be a dotted line extending the frame member to the outer edge of the adjoining member and a circular style gusset that would be used between the frame members for a lapped joint. There have been too many of these built to think that there was an error in the patterns that glaringly large.

Here is an example of a lapped joint on the Zip (larger version of the Flying Saucer) and a frame from the Torpedo which has a butt joint on the chine and a lap for the shear. Butt joint shown open prior to gluing with gusset.

You should draw out the framing and use a mirrored half frame and lay out the complete framing on the full size patterns.

Roberta

Re: Frame 2 does no match plan

Posted: Sat Feb 16, 2019 2:04 pm
by Roberta
Here you can see how I started drawing out all the frames on my layout board. Then the frame members were cut and shaped to properly fit the patterns and assembled on the board. Wax paper helps protect the parts from sticking to the board.

There could be a small amount of shrinkage over time in patterns, By drawing them out, corrections can be made before cutting begins. Adjusting the centerlines may be necessary to get correct overall dimensions.

Roberta

Re: Frame 2 does no match plan

Posted: Sat Feb 16, 2019 8:41 pm
by Wawa2c
Hello All

Thank you for the tips. I enjoy seeing others approaches. I have read completely all information received with the plans plus referencing Boatbuilding with Plywood book.

Result so far is two frames (see picture #1) both of which are dead on to the patterns.

Frame 2 does not match the measured dimensions. Measurements on the plan indicate center line to sheer is 34 1/2 inches. (picture #2)

Measuring directly off the pattern sheet gives a distance of 33 3/4". (picture #3) Even measure at a diagonal it is still short.

On the transom, it's supposed to be 25 1/2 from center line to chine but it is 3/16" short

Re: Frame 2 does no match plan

Posted: Sun Feb 17, 2019 6:47 am
by billy c
Well, my first choice would have been layout the pattern and make the adjustments to match the plan, if dimensions were given. The second would be build to the “full size” pattern realizing the dimensions will vary slightly and make adjustments to the slots for Chine keel sheer etc. Either would produce the final results after fairing is complete
Billy

Re: Frame 2 does no match plan

Posted: Sun Feb 17, 2019 7:57 am
by Bill Edmundson
Jonathan

I'd use it as is. Set the side to the dimension so that the corner is where it is supposed to be. Most of that material is cut out for the notch. Even more will come off in the fairing process.

Bill

Re: Frame 2 does no match plan

Posted: Sun Feb 17, 2019 7:05 pm
by hoodman
You might just put a call in to Glen-L. You might be okay as is but they should be able to tell you for sure and put your mind at ease.