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  #31  
Old 01-13-2007, 11:42 PM
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Carl@Semroc Carl@Semroc is offline
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Quote:
Originally Posted by CenturiGuy
I was thinking just today that I need to go down to the tool store and pick up some Dial Calipers to determine what the tolerance should be, since the prototype guides below fit *real* (i.e., "too") snugly.
The tolerance for 3/32" balsa is +/- .010". If the guide is cut for the .103" "thick" balsa, the slots are too wide for the .083" balsa.

OR select a tighter range just for this kit.

Quote:
We need to cut some "triangles" to allow room for the fillets, so the fin guide doesn't get glued to the rocket.
Thought about that after I shipped them!
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  #32  
Old 01-13-2007, 11:44 PM
James Pierson James Pierson is offline
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Thanks for the info Carl. And I agree with Made in the USA.

Quote:
We have checked into molds for nose cones. The best price I could find was $5K per nose cone! When I mentioned that to Bill Stine, he said I could get those in China for about $800. I mumbled that it did not look like we would be doing nose cones. I refuse to deal with China. I think I am too old to start trying to get along with them now.
/rant



Maybe what we need is a heavier washer wieght that is dishes out that will still work with an eye screw. I have developed a way of hollowing out the BNC to install clay without messing up the coulper part of the cone, but it is not for beginner rocketeer's .

Thanks, JP

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  #33  
Old 01-13-2007, 11:46 PM
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Or you could make them out of plastic or basswood and include them in that deluxe kit (the fin fixture/jig/guide things).


I think that Semroc has it right, MADE in the USA and balsa nose cones.
The balsa cones set up nicer, are very "fixable", I just think they are "better" overall.
I deal with Russia, China, and India on certain parts for my work. If I could get away with not doing it, I would. But not many places that can stamp out a AK-74 parts set for replacement for so cheap and on the original machines with the original technical package.




Quote:
Originally Posted by CPMcGraw
I made it a habit with the BARCLONE PDF plans to draw a fin guide like the one Jay has in his photo. (In fact, I think that's one I drew up for him on that project... ) I have found these simple cardstock holders to be just about as accurate, although I wished my own had been a bit thicker (and stiffer) at times. Carl's 0.07" cardstock would make ideal disposable guides which could be included in every kit at a nominal premium.
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  #34  
Old 01-13-2007, 11:47 PM
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CPMcGraw CPMcGraw is offline
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Quote:
Originally Posted by Carl@Semroc
We have checked into molds for nose cones. The best price I could find was $5K per nose cone! When I mentioned that to Bill Stine, he said I could get those in China for about $800. I mumbled that it did not look like we would be doing nose cones. I refuse to deal with China. I think I am too old to start trying to get along with them now...


The other thing I thought about, concerning plastic items, is the time-to-market delay. In the time it takes for one plastic tooling to be created, tested, revised, tested again, put into production, shipped, and finally received in the warehouse / packaging room, that Krellvenator could have produced multiple batches of the same cone and the kits could have been on the dealer shelves. The quicker turn-around time is worth any premium a balsa cone might cost, if there actually is any.

I'm not personally in favor of an injection-molded cone at this time. We've seen some applications already on this forum -- the Tau Tau is a good example -- of where a hollow, blow-molded plastic cone might be usable; and if SEMROC did venture into plastic that is what I might suggest. But I think the balsa components give these kits a feel that plastic takes away. I'd just as soon not see plastic used right now. Estes and Quest are in that camp. Their QC is in dire need of attention, and off-shore tooling is just one issue. Let's just "not go there"...
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  #35  
Old 01-13-2007, 11:48 PM
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Tau Zero Tau Zero is offline
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Talking Fin Alignment Guides

Quote:
Originally Posted by CPMcGraw
I made it a habit with the BARCLONE PDF plans to draw a fin guide like the one Jay has in his photo. (In fact, I think that's one I drew up for him on that project...
Oh, *so* close, Craig, but *no* cigar!

For the rest of you, this was Craig's original fin guide:

http://forums.rocketshoppe.com/show...8&postcount=124


And here it is in operation:

http://forums.rocketshoppe.com/atta...tachmentid=3383


Quote:
I have found these simple cardstock holders to be just about as accurate, although I wished my own had been a bit thicker (and stiffer) at times. Carl's 0.07" cardstock would make ideal disposable guides which could be included in every kit at a nominal premium.
Does that translate to 6-ply? I think these are 2-ply. Right, Carl?


Cheers,
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  #36  
Old 01-13-2007, 11:58 PM
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Red face Nigglin' details

Quote:
Originally Posted by CenturiGuy
We need to cut some "triangles" to allow room for the fillets, so the fin guide doesn't get glued to the rocket.
Quote:
Originally Posted by Carl@Semroc
Thought about that after I shipped them!
Yeah, well, *I* didn't think of it until I "tried them on for size" with a Tau Zero prototype.


Quote:
The tolerance for 3/32" balsa is +/- .010". If the guide is cut for the .103" "thick" balsa, the slots are too wide for the .083" balsa. OR select a tighter range just for this kit.
I'll have to get back to you on that.


Cheers,
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03 Sept 2014
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  #37  
Old 01-14-2007, 07:40 AM
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Quote:
Originally Posted by Carl@Semroc
Did not think of that! We just gathered up some "blems" that were laying around and "posed" them.

The lack of larger printed chutes and manuals have kept us from doing the "specials."

One special I always wanted was a set of all the body tube sizes in very short (2-3") lengths. I have access to that now. When I am building a rocket, I use a short piece of tube to fit the nose cone, then sand it, fill it, and paint it. THEN I finsih the actual body tube. This keeps all the sanding and layers of filler coat off the final tube. The short piece is then thrown away. I used to think that everyone did that.


In the past, a lot of the parts that came with the Estes original Designer's Special (which had
stayed with me since the 1970's) also came in handy when I needed to make quick repairs/
rebuilds of my NAR contest "rated" models (especially the boost/rocket gliders and, on my
most recent "overnight" build, an 18 mm helicopter duration model -- the Gassaway styled
design). Speaking of which is why I need another "Designer's Special" as most all of the parts I had have been used up
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  #38  
Old 01-14-2007, 08:32 AM
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Quote:
Originally Posted by Carl@Semroc
...

We do have a plastic angle we use with Scout groups, but it is not online. We are thinking of providing fin marking rings like Estes used to provide on some kits.


I have small scraps of popular tube sizes already pre-marked for 3 and 4 fins. I socket the tube onto the body tube I need marked and use my angle stock to extend the pre-marked lines. Zip zip zip... done!
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  #39  
Old 01-14-2007, 08:41 AM
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John Brohm John Brohm is offline
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Quote:
Originally Posted by Carl@Semroc
The tolerance for 3/32" balsa is +/- .010". If the guide is cut for the .103" "thick" balsa, the slots are too wide for the .083" balsa.

OR select a tighter range just for this kit.

Thought about that after I shipped them!


When I lay out my templates, I try to cut the slot width as precisely as possible, for just this reason. The tolerance on the balsa, plus the fact that I like to tissue the fins, means the slot width will vary slightly from project to project anyway. So making the templates out of matte board gives me something that I can sand to fit the width of the particular fins I'm using (also, the thickness of the matte board makes for a very sturdy template which makes for a better support). When the template gets too loose, I just make another one. Another reason to keep them cheap!

And as has already been pointed out, it's highly advisable to chamfer the slot points to make room for glue fillets (!).
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  #40  
Old 01-14-2007, 08:56 AM
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Quote:
Originally Posted by Eagle3
I have small scraps of popular tube sizes already pre-marked for 3 and 4 fins. I socket the tube onto the body tube I need marked and use my angle stock to extend the pre-marked lines. Zip zip zip... done!


Excellent idea! It never occurred to me to do that, but I use scrap tubing for everything else.
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