Fin Jig

whats the best fin jig for rockets out there?

Unless you want a Rose Jig for precision my favorite is...from PayloadBay.com https://www.payloadbay.com/index.php?page=Tools&action=FINGUIDES

Simply enter the fin span, airframe diameter, number of fins, and fin thickness, hit submit button and it creates a PDF file that you can print and glue to a piece of artists foam core board. The one in the picture below is for a Loc 5.38" airframe Cherokee-D upscale and the guide is printed as 4 pages that are easy to line up (simply tape together and glue to foam board). I cut notches near the fin roots to keep from gluing the guide to the airframe.

Depends on what you're doing.

People seem to make due with everything from this: https://www.payloadbay.com/index.php?page=Tools&action=FINGUIDES

to this: https://www.apogeerockets.com/Building_Supplies/Tools/Guillotine_Fin_Jig

or even this: https://www.estesrockets.com/rockets/accessories/302231-fin-alignment-guide

I know of three commercially available fin jigs for rockets, there may be others.

Estes https://www.estesrockets.com/rockets/accessories/tools-supplies/302231-fin-alignment-guide




Apogee https://www.apogeerockets.com/Building_Supplies/Tools/Guillotine_Fin_Jig





Rose https://www.hightechrocketry.com/FinJig.html




I own none of them but I have used the Guillotine and I can say it works as advertised. I think you'll find many threads here with the DIY ingenuity of handy TRFers.

I'm not sure it answers your question about "best" but I hope the info is helpful.

These ones look nice. https://qualmanrocketry.com/Fin_Guides.html

I intend to try them when I can afford it, but til' then I'm quite content with the Payloadbay versions, even making them from just 110# cardstock and soaking the paper with super thin CA for really small stuff like 13mm and MMX.

samb said:

I know of three commercially available fin jigs for rockets, there may be others.

Estes https://www.estesrockets.com/rockets/accessories/tools-supplies/302231-fin-alignment-guide

View attachment 289271


Apogee https://www.apogeerockets.com/Building_Supplies/Tools/Guillotine_Fin_Jig

View attachment 289272



Rose https://www.hightechrocketry.com/FinJig.html

View attachment 289273


I own none of them but I have used the Guillotine and I can say it works as advertised. I think you'll find many threads here with the DIY ingenuity of handy TRFers.

I'm not sure it answers your question about "best" but I hope the info is helpful.

Click to expand...

I own all three. The Rose jig is the best, but He passed away so it is likely not available. The guillotine is next best and will work for just about all builds.

The Estes jig is useful for low power.

There are also these available:

https://www.bmibay.net/finjig.html

I have a set of these for LPR. Works nicely.

https://www.qualmanrocketry.com/Fin_Guides.html

samb said:

I know of three commercially available fin jigs for rockets, there may be others.

Estes https://www.estesrockets.com/rockets/accessories/tools-supplies/302231-fin-alignment-guide

View attachment 289271

Click to expand...

I was never able to get my Estes alignment guide to work well enough for my tastes. Too many of my rockets were capable of sitting on their fins, and I wasn't able to reliably able keep the body tube elevated enough to ensure that the third (or fourth) fin applied would even with where it was supposed to be attached (they were always higher than they should be). Also there was too much "slop" in the fitting to keep the fin straight. Mine ended up being only used as a temporary stand for rocket that can't stay upright on their own.

I'm a big fan of the PayloadBay tool.

cwbullet said:

The Rose jig is the best, but He passed away so it is likely not available.

Click to expand...

The Rose jig is available at the link https://www.hightechrocketry.com/FinJig.html. The fellow who is making them now (I don't recall his name) was showing them and selling them at NARAM 54 where I saw one in person for the first time. Someday......

BEC said:

The Rose jig is available at the link https://www.hightechrocketry.com/FinJig.html. The fellow who is making them now (I don't recall his name) was showing them and selling them at NARAM 54 where I saw one in person for the first time. Someday......

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Worth the investment if you have the cash.

All those look complicated and pricey. I built mine for $6... I'll post pics when I get home. The print and cut ones work great, too...

CzTeacherMan said:

All those look complicated and pricey. I built mine for $6... I'll post pics when I get home. The print and cut ones work great, too...

Click to expand...

Would that be the one that is made from a couple of 2x4s with a diagonal cut down the length of it, some melamine board, and a few pins?

I wish I could find the image of that jig, as it looked like a way to get fins applied perfectly straight to prevent rolling (perfect angels between fins were not guaranteed, but they'd be perfectly straight no matter what).

K'Tesh said:

Would that be the one that is made from a couple of 2x4s with a diagonal cut down the length of it, some melamine board, and a few pins?

I wish I could find the image of that jig, as it looked like a way to get fins applied perfectly straight to prevent rolling (perfect angels between fins were not guaranteed, but they'd be perfectly straight no matter what).

Click to expand...

You're talking about Micromeister's home brewed creation, I think. Like I said, a lot of TRFers are pretty handy in the workshop.

K'Tesh said:

Would that be the one that is made from a couple of 2x4s with a diagonal cut down the length of it, some melamine board, and a few pins?

I wish I could find the image of that jig, as it looked like a way to get fins applied perfectly straight to prevent rolling (perfect angels between fins were not guaranteed, but they'd be perfectly straight no matter what).

Click to expand...

Basically yes. I made mine out of MDF and carriage bolts. I also made it so it can scale to larger tubes. Which came in handy when I built my 8" L3 rocket. I'll post pictures when I get home. So easy and it works on Estes through maximum HPR.

I've been enjoying my 3d-printed fin jig:


Description and exciting (?) action shots may be found here. It doesn't do everything, but it sure gives me straight fins. I still ponder ways to make it better.

More than anything, the design and print process was a lot of fun; I used Tinkercad and 3dHubs. It was my first foray into 3D printing, and I'm hooked.

I made mine from some plastic exterior trim "boards". I've used it on 29 to 98mm rockets. You place a spacer the same thickness as the fins between the two halves.

Tony

I use the Payload Bay print and cut ones, even for my (gasp) Level 3 rocket. I also use JB Weld one the fin root. The thickness of it allows you to do all three or four fins at the same time, held on by the fin guide.

Bat-mite said:

I use the Payload Bay print and cut ones, even for my (gasp) Level 3 rocket. I also use JB Weld one the fin root. The thickness of it allows you to do all three or four fins at the same time, held on by the fin guide.

Click to expand...

I used the Payloadbay tools to make a pair of fin quides for the Ultimate Dark Star.

For smaller rockets have had some fg ones that came with the blackhawks .. but 2.6 , 3 inch and 4 inch have made them all out of foam board with Frywrxz Daves help.

Attached is the mockup .. before glueing

Kenny

I have to say, I never understood why some folks have had bad luck with the Payloadbay templates.
I have had nothing but good results with them so long as I do my part and prepare them with attention to detail and precision.
I build mostly rockets with four fins and four wings, and I'm planning and working on a couple that have canard fins too, for a total of 12 pieces.
I use an aluminum angle to make everything align with the axis of the body tube, and my rockets don't twist, which is testament to the accuracy of the Payloadbay tool.

I'm about to start playing around with hot wire cutting of foam, and one of my first projects is a nice set of fin jigs and a rocket cradle.
I'll glass the foam ofcourse, but I want and require a nice, professional looking set of tools, so I'll make them.

The method I use is similar to the Payloadbay template. I happen to use my own templates (from PowerPoint) but the concept is the same. Obviously, the template keeps the fin at the correct angle relative to the body tube. Then, I use two pieces of angle iron to actually hold the fin in place, and I make cut-outs in the template so that the angle iron can extend all of the way past the fin and the end of the body tube. When the angle iron is laid on the body tube, it aligns with the tube and can't wiggle around at all. It's just a variation on the Estes door jam approach. The two pieces of angle iron lock the fin in a perfectly aligned position (it is very difficult not to get perfect alignment with this method). The two pieces of angle iron are a little difficult to see in the picture, but they are there.

The method only works with flat fins, and it is helpful to vary the size of the angle iron in proportion to the body tube diameter. It is also helpful to inspect the angle iron when you buy it, as every now and then, I find a piece that is not straight.

When I do fins, I coat the root with epoxy except for two gaps at either end where I put a few drops of CA. I set up the template and angle iron, remove the fin and apply the glue, and then position the fin back in the template. It takes about half an hour to install a set of fins.

Jim

samb said:

You're talking about Micromeister's home brewed creation, I think. Like I said, a lot of TRFers are pretty handy in the workshop.

Click to expand...

Thanks for the info... There were some beautiful shots of it in action somewhere, but I can't remember where to look. I guess I'll try looking up his name and jig, and see what pops up.

CzTeacherMan said:

Basically yes. I made mine out of MDF and carriage bolts. I also made it so it can scale to larger tubes. Which came in handy when I built my 8" L3 rocket. I'll post pictures when I get home. So easy and it works on Estes through maximum HPR.

Click to expand...

Sounds like what I was trying to describe. IIRC, there was some discussion about using melamine board because its not prone to warping from changes in humidity or temperature.

tfish said:

I made mine from some plastic exterior trim "boards". I've used it on 29 to 98mm rockets. You place a spacer the same thickness as the fins between the two halves.

Tony

Click to expand...

That's the style I was thinking of. Thanks for the images!

Ya, here's a pic of mine. That's a Demon 98... 4" tube works fine.
When I built mine, I had one 2'x2'piece of MDF thati used to cut 4 sheets. I stacked them 2x2 and cut my angles that way. Drilled holes through all 4. Hence, I have two fin jigs or can attack them and make one large, fat jig, like in the second picture (8" tube)

TopRamen said:

I have to say, I never understood why some folks have had bad luck with the Payloadbay templates.
I have had nothing but good results with them so long as I do my part and prepare them with attention to detail and precision.
I build mostly rockets with four fins and four wings, and I'm planning and working on a couple that have canard fins too, for a total of 12 pieces.
I use an aluminum angle to make everything align with the axis of the body tube, and my rockets don't twist, which is testament to the accuracy of the Payloadbay tool.

Click to expand...

I think the concern about the PayloadBay tool is that you only have one point of attachment, and if you're not careful, you can accidentally install a fin that is canted and thus induce a roll. Of course with TTW building methods, this doesn't happen, unless the slots for the fin tabs are really sloppy.

Another point that can't be stressed enough (I know it's been mentioned before, but it's really important) is that you MUST cut a small notch at each fin/body tube joint to prevent yourself from gluing the guide to the fin.

And lastly... Labeling your fin guide is another useful step. For my four finned rockets, I cut the guide square, and for three finned rocket, triangular (to save on the foam core, and fast ID purposes), this usually crops off the dimensions of the fins. So, writing them down on the guide helps when you've got multiple rockets with similar (yet different) dimensions. For example, a BT-55 or a BT-56 body tube.

K'Tesh said:

I think the concern about the PayloadBay tool is that you only have one point of attachment, and if you're not careful, you can accidentally install a fin that is canted and thus induce a roll. Of course with TTW building methods, this doesn't happen, unless the slots for the fin tabs are really sloppy.

Another point that can't be stressed enough is that you MUST cut a small notch at each fin/body tube joint to prevent yourself from gluing the guide to the fin.

Click to expand...

The reason I don't use them is the extra step of cutting out a fin jig and needing it to be precise in order to have precise fin alignment. I know many people use them and are very successful. Just, for me, it's just super simple to use my jig they it's kind of idiot proof, which means it's me-proof. Using the jig, I literally can't have anything except straight fins. So, the print and cut jigs need me to be precise to get precision. My jig... All I have to do is use it and I can't fail to get straight fins no matter what.

What technique do you use to accurately cut out the template from the foam core board? I find foam core board to need several passes with a hobby knife and the cuts don't always seem very precise.

Best regards,
Brian

BRS Hobbies said:

What technique do you use to accurately cut out the template from the foam core board? I find foam core board to need several passes with a hobby knife and the cuts don't always seem very precise.

Best regards,
Brian

Click to expand...

I just glue the PDF pattern to the foam board with spray adhesive, and use a metal ruler and a new sharp No.11 Xacto blade and just try to keep the blade as close to vertical as I can, it still takes several passes through the material ( 1/4" foam board). As long as I haven't misaligned the larger patterns, or totally messed up cutting the smaller ones the alignment is right on.

BRS Hobbies said:

What technique do you use to accurately cut out the template from the foam core board? I find foam core board to need several passes with a hobby knife and the cuts don't always seem very precise.

Best regards,
Brian

Click to expand...

I cut the paper template first before gluing it to the foamboard. Then, when I am cutting the foamboard, I make sure to start with a brand new Z-Series #11 X-acto blade. I tune it up with an emery board for the fin slots and some sandpaper on a dowel for the round part.
I like them to be perfect, so since I got my digital caliper, I measure and adjust them accordingly. The digital caliper has become one of my most used tools as of late.
As far as fin cant, you can always make more than one fin guide if you need it, but I have had good luck tacking the fins into position with superthin CA, so they don't shift while the epoxy cures.

Here is a video I first saw on Rocketry Planet which inspired me to develop the Guillotine Fin Jig. It's like what the PETA folks always say, "There's more than one way to skin a cat."

[video=youtube;EwvKR5Lfolk]https://www.youtube.com/watch?v=EwvKR5Lfolk[/video]