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Wanted Art Rose Fin Jig

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Siya

Well Known Member
Joined
Dec 24, 2018
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I'm looking for the Art Rose Fin Jig (High Tech Rocketry) and I'm willing to pay whatever price for it.
 
They don't sell it anymore. I tried to contact the company but their email doesn't even work anymore.
 
Wow, that's pretty cool. But how much for just 1?

Well, according to the link to the website . . .

Fin Jig, $440.00 without mandrels
Mandrels 10.5mm, 13mm, 18mm, 24mm @ $35.00 each
Custom mandrels any size up to 29mm @ $47.00 each
Auxiliary Arm (increased fin span, offset positioning ) $40.00
 
To put fins on model rockets? It does look like a nice piece but for that kinda dough I think I'd start looking for a small mill/rotary table that has more than one trick up its sleeve.
 
To put fins on model rockets? It does look like a nice piece but for that kinda dough I think I'd start looking for a small mill/rotary table that has more than one trick up its sleeve.

Agreed . . . I always thought that unit was overpriced, probably why I never bought one - LOL !
 
I made one for my son last year before he went to the world spacemodeling championships in Poland .

I am currently building a few more to sell , as a fundraiser for the next wsmc ( Romania 2020 ) assuming he makes the team again.

IMG_1113.jpg
 
I made one for my son last year before he went to the world spacemodeling championships in Poland .

I am currently building a few more to sell , as a fundraiser for the next wsmc ( Romania 2020 ) assuming he makes the team again.

That looks pretty neat.
Please add me to the list of perspective customers/fundraising contributors!

a
 
Dan, I have no want to make a profit nor to derail your sales. My goal is to build a project to help others who can't afford a premium product. If it truly is an abandoned product, I am sure we could 3d print one as a group. The poster is from South Africa according to his IP.
 
Chuck thanks I didn’t know the OP was from South Africa.

Guynoir sorry no I don’t plan to share the files anytime soon , it will be hard to sell them if I give away the files to print for free. I was planning to sell a 3d printed version as well as an anodized aluminium one.
 
I disagree about being able to sell them if you share the files. There are probably plenty of us who would love to own one of these but can not afford a 3D printer. I personally would love to have two of these, one for smaller rockets, and one for the bigger ones. The key would be to make them affordable to a larger segment of rocketeers. What are your price points?

I also think this would get more input in a separate thread, I only started looking into the for sale or wanted very recently and yet find where this is going of great interest. I am sure others would too. Perhaps ground support or watering hole???
 
Dan,

I would like to order the aluminum art rose jig that you are planning to make. I have a couple of minimum diameter rockets that I plan to launch at Balls. Please respond to my PM.

Siya
 
Siya , I don’t think the finjig will work for your mongoose 98 .
 
Hi Dan,

I could use centering rings and a coupler to adapt the jig to a 4 inch airframe. The original jigs came with mandrels.
 
Hi Dan,

I could use centering rings and a coupler to adapt the jig to a 4 inch airframe. The original jigs came with mandrels.

the original said it was only good for airframes up to 3” . The problem is the plate the fin lays on can only be moved so far away from the mandrel. Also the size of fins you would be trying to put on are about 10x the size of the plate .
 
Long ago I watched Art use his own jig to speed build FAI contest models. It was pretty impressive, but that *is* the design target for the way this unit is built, and there are not many folks for whom the ability to rapidly build many identical, small LPR contest models with consistent fin alignment is worth a fair amount of money. A couple of years ago I had some extended conversations with Geoffrey Kerbel about the jigs (Geoffrey was an experienced machinist who had been working on production of new jigs in direct collaboration with Art while Art was still around). Many of you probably know that Geoffrey himself passed away during NARAM last year.

One thing I'd say up front for people who are concerned about the cost is that given the amount of machining needed, the pricing for a metal unit seems fair. And I don't think that making a mostly 3d-printed version is going to be too easy. The Rose jig design depends on holding a fair amount of rigidity despite cantilevering both the rocket body spindle and the fin support plate.

I'm just throwing the following information out here so that it won't be lost.

One of the design issues that Geoffrey and I talked about was the fin thickness adjustment mechanism. It's kinda handy but it becomes the upper bound on rigidity and perpendicularity of the fin support plate due to the small bearing surface sliding in the little track. An idea we discussed was to eliminate the screw adjustment and instead make a small number (maybe 3) of thickness-milled plates with a consistent thickness at the mounting end (~0.25") that could be bolted to a beefier and higher precision support angle with substantially more bearing surface. The bolt pattern could be done to provide a considerable range of positioning for the fin support plates, and help enable swept fins, avoidance of tail cones, etc. that the original design is not well suited for. I'm probably going to build my own unit this way, but that might make costs too high for a production run given the extra fly cut / face mill operations needed.

The other design issue, especially for scaling up to a larger version, is runout on the spindle. In the original LPR unit you have a fairly thin steel shaft passing through holes drilled in a pair of aluminum plates that are less than 1" apart, secured by collars on each side. This is the simplest possible implementation but is also the least accurate and most prone to wear. It's adequate for light LPR models. I haven't seen the larger model in person so I don't know what Art and Geoff did differently there. Improvements: 1) install some press-in bronze bushings. Doesn't help runout directly, but costs little and limits wear. 2) Increase spacing of bearing plates - reduces runout linearly. 3) increase diameter of spindle shaft - reduces runout both due to flexure and ratio of shaft size to hole/bushing fit tolerance 4) Use actual shaft bearings - best result but highest cost.
 
With Geoffrey's personal Rose Fin Jig now in my possession (this is the one that was for sale a few weeks ago) and having used it on a couple of builds so far I find Dave's assessment just above is spot on. I especially agree that simply scaling it up while maintaining its precision would be challenging.

Dave's comment that the design "requires a fair amount of rigidity" is why I questioned the idea that a 3D printed version using the same basic design would work as well. That comment I think is now in the other thread that Chuck split off from this one.

I first saw one of these (maybe even the unit I now have) in a conference room at NARAM-56 where it was left out for anyone to use. I still can't wrap my mind around people building contest models at the hotel the night before they fly them....but it was used by quite a few folks then. At the time I choked at the price even though I could see that it was fair for what it is. At the time I was attending my first (and I expected, only) NARAM and didn't think I'd ever really need such a tool. I regretted my decision not to buy one from Geoffrey back then almost immediately....and find it an odd bit of irony that I now have his personal unit.

That said, it is a very satisfying tool to use, just as using anything that is high quality is satisfying to have and use.
 
Any updates on this? I am still looking for an Art Rose Fin Jig.
 

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