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-   -   Harrison Competition Fin Jigs (http://www.oldrocketforum.com/showthread.php?t=18439)

Gus 04-14-2020 11:53 AM

Harrison Competition Fin Jigs
 
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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

BEC 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.

Gus 04-14-2020 12:03 PM

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.

BEC 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.....

ghrocketman 04-14-2020 01:15 PM

I understand the need for these in competition models.
For sport I do not in the least.

Gus 04-14-2020 02:40 PM

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. :)

joltinjoecanada 04-14-2020 03:02 PM

Quote:
Originally Posted by Gus
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
. Am I right in assuming that it comes with mandrels for BT-5, BT-20 and BT-50? How expensive is 'expensive'?

Certainly looks like a quality lifetime unit.

Gus 04-14-2020 03:59 PM

Price through ebay is $500. ~$100 less if you contact me and I put you in touch with Dan.

Mandrels are 10.5 mm, 13 mm, 18 mm. (BT-4, BT-5, BT-20) Larger mandrels are available for an additional fee upon request.

Here is the text from the ebay listing:

Simply put, this is the very best model rocketry fin jig you can buy. Nothing else on the market even comes close. Although you can put fins on an Estes Alpha with it, that is not what it was designed for. This fin jig is a piece ultra high precision equipment for completely controlling all degrees of fin placement. It allows for very simple, precise, absolutely repeatable fin placement capable of allowing world class competition modelers to compete with the best in the world.

For many years world class competition fliers used a fin jig designed and built by Art Rose. Art was a U.S. and International medal winning competitor who also happened to be a really talented machinist. For years Art made his fin jigs available and they were highly prized by U.S. and International competitors. In fact, they are so highly prized that you never see one offered for sale on eBay or anywhere else.

But when Art passed away a few years ago, the fin jigs became completely unavailable.

Then my son started competing.

And I am a machinist.

So I borrowed one of Art’s fin jigs from a friend and I created my own version. These competition level fin jigs are identical to the original with some new features added. Art’s original jigs had preset hole locations for 3-finned rockets. I added additional holes to allow absolutely precise fin placement for 4-finned rockets as well. There is also a dial on the end of the rotation wheel to all precise fin placement for any number of fins to within 1 degree of whatever you desire. In addition, I had all the aluminum hardware anodized blue (both for part protection and because it just really looks cool, LOL)

As I said at the outset, this is simply the highest precision fin placement jig that you can buy. Nothing else on the market even compares.

The fin jig comes complete with mandrels for 10.5mm, 13mm, and 18mm tube sizes (BT-4, BT-5, BT-20). If you would like, for an extra fee, I can also make other sized mandrels for you.

It also comes with 3 Allen keys for the mandrels.

A great rocketeer once said “straight fins are good. Straighter fins are better. Straightest fins are best. For sport rockets, fin placement is important. For competition rockets, fin placement is vital.”

Even if you are not a competition flier, if you want the very best fin placement possible, this is the tool you need to own.

BEC 04-14-2020 06:03 PM

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.

ghrocketman 04-14-2020 06:28 PM

I can understand using it for sport models if one has it already for competition rockets.
I probably spend about $1000 each year on rocket stuff other than motors.
I just can't however see a jig ever being worth about a half-year's rocket budget.
I'll just stick to the tried-and-true TLAR method of a well calibrated eyeball and a steady hand.


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