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Old 04-14-2020, 11:53 AM
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Gus Gus is offline
7/21/61
 
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Default Harrison Competition Fin Jigs

Just wanted to give a head's up that Dan Harrison's Art-Rose-Style fin jigs are now available again. Dan has them listed on eBay here.

Because of Ebay and Paypal fees Dan has to charge considerably more on eBay than he is willing to accept directly. If you are interested in buying one, PM me and I will put you directly in touch with Dan to save you considerable money.

And yes, these are expensive. They allow ultra-precise fin placement for anyone trying to compete at world-class levels, or who just wants the best fin placement attainable.

Steve
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Old 04-14-2020, 12:00 PM
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Highly recommended.

And no, it's not just for competition models.

Here is mine in use on the Estes Olympus.

Note that I have a 24mm mandrel which is extra.
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Old 04-14-2020, 12:03 PM
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Bernard,

I am fascinated by your spring steel gizmo holding the fin to the platen. Can you explain it a bit and maybe get me a photo from the side. Looks like a really good idea for larger fins.
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Old 04-14-2020, 12:53 PM
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Quote:
Originally Posted by Gus
Bernard,

I am fascinated by your spring steel gizmo holding the fin to the platen. Can you explain it a bit and maybe get me a photo from the side. Looks like a really good idea for larger fins.


Steve,

I've had those things (in two sizes) for a loooooong time—I'd guess close to 40 years. I got them at a hobby shop that closed many years ago for clamping model airplane parts together.

I suspect the vendor is also long gone.....
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Old 04-14-2020, 01:15 PM
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I understand the need for these in competition models.
For sport I do not in the least.
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Old 04-14-2020, 02:40 PM
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Quote:
Originally Posted by ghrocketman
I understand the need for these in competition models.
For sport I do not in the least.
GH,
I agree. Definitely overkill for sport models. But like Bernard, if you have one, once you start using it, you don't build anything without it. It's not just that it's really accurate. It's that it's so easy.

With me it's actually, "hey, this thing is WAY better than me at putting on fins," LOL. I'm more than willing to admit my inadequacies.

Now if I can just find a similar tool for sanding.
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Old 04-14-2020, 06:03 PM
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Quote:
Originally Posted by ghrocketman
I understand the need for these in competition models.
For sport I do not in the least.

You are quite correct - it is not a need. But as Steve pointed out, once one has this tool, it's hard not to use it.

I think there is one model I have currently underway that I didn't use this tool on, just because I couldn't figure out a way to get any benefit from it - and that's a Silver Comet. There instead I followed jeffyjeep's V-2 suggestions for the build of the motor mount, tail cone and fins. But otherwise, as Steve said, it's better than me.

Recently I did the little two-stager called Sterling Silver (I know, boring) using it and that thing flies dead straight and with essentially no roll, on boost and sustainer. It adds, for me, quite a bit of cool factor when model works that well.

But is it a need? No. Use of something, for example David Qualman's laser-cut fin alignment jigs, really helps, but good lines on the tube and a well-calibrated eyeball can certainly do "good enough" for sport models in particular.


joltinjoecanada: I actually already had the 24mm mandrel (and some larger ones) as I obtained Geoffrey Kerbal's Rose jig from his estate (with more than a little help from Steve - this was before I knew of Dan Harrison's newly-made ones). But Geoffrey had used it so much that it was a bit sloppy in places and I came to NARAM-61 with the idea that I might buy one of Dan's newly made ones....and as you can see, I did. However the mandrel (and the clamp and ball/socket base you can see in my picture - the parts that aren't anodized blue) are actually from the one I got from Geoffrey's estate.
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Old 05-13-2020, 04:25 PM
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Quote:
Originally Posted by ghrocketman
I understand the need for these in competition models.
For sport I do not in the least.


Simple economics . . . If you just dropped $400-$500 on one of these units, you had better USE it, as OFTEN as possible !

Dave F.
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Old 04-18-2020, 10:36 AM
aiglesia aiglesia is offline
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Quote:
Originally Posted by Gus
Bernard,

I am fascinated by your spring steel gizmo holding the fin to the platen. Can you explain it a bit and maybe get me a photo from the side. Looks like a really good idea for larger fins.

I think that those springs are constant force springs.
You can buy them on McMaster Carr in many sizes and strengths
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Old 05-09-2020, 12:07 AM
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Default Even works for MMX models

I don't know if Art Rose planned it this way or if it's just lucky happenstance, but the shaft which carries the mandrels is a pretty close fit to a MicroMaxx motor tube. Just a touch of blue tape is required to make it a snug fit.

Semroc MMX Goblin getting its last fin on earlier today:
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