CNC vs. standard hole cutter vs. bandsaw

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Well-Known Member
Apr 7, 2004
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Just wondering if anyone thinks CNC cut rings or fins are necessary when buying kits in the $30+ range. We (Rocketguts) might post this data on our website to attract dealers and large buyers.

Thanks for your input
Personally, I do not think it really matters if they are both good quality and fit in the tube, although, I can see when buying a really expensive kit where you might want cnc.
CNC is not necessary. With a little bit of set-up and trial and error, I can get great results from my drill press. It's also kinda better than CNC because it leaves a rough edge for the glue to grab into, as opposed to the smooth edge.

I believe that you are talking about rings in kits. In that case, I would like to see a good quality CNC or laser cut set of rings in a moderately expensive kit. They are not necessary, but would certainly make the kit easier to build.


What matters to the end user is the quality of the fin, not the manufacturing method.

A CNC, a laser cutter, a die cutter, or standard sawing/sanding will produce equally good results. If you making them for sale, you as the manufacturer have to determine which method is right for you.

Bob Krech
Originally posted by bobkrech

What matters to the end user is the quality of the fin, not the manufacturing method.

Exactly. It could have been gnawed out by rats for all I care. As long as I can't _tell_ it was gnawed out by rats. ;)
But don't you all think from an advertising stand point, it would be beneficial to be able to say the parts in your kit are CNC cut, rather than with a hole cutter or bandsaw?
I think precision cut rings are a must in any kit. Whether that precision cut is achieved by a laser, CNC router, drill press, whatever.

Unless this is achieved (in my opinion) all you are selling is a bag of parts for scratchbuilding a rocket with a set of plans.

Fins, however, need not be as precise in measurement and fit as rings do and therefore cutting them ourselves is acceptable.

The more work that is done by the supplier/manufacturer (cutting fins, cutting and/or slotting tubes, providing the appropriate rings) the more the bag of parts becomes a true "kit."

I hope this makes sense.
The real value of CNC is the cost to the supplier. CNC is great if you're making large batch of things, cost goes way down. For one-offs, making it by hand is faster and cheaper. If you use CNC you can offer lower priced kits to your consumers ( or make larger margins), assuming you can sell that many.

Saying CNC makes you look good but that's about all. If you're selling them, people expect them to be the right size, no matter how you cut them. But hey, looking good is part of marketing, right?
Originally posted by Fore Check
Fins, however, need not be as precise in measurement and fit as rings do and therefore cutting them ourselves is acceptable.

Call me crazy, but I feel just the opposite. IMHO, centering rings can be a little under (loose) or over cut (snug), but that's nothing that either a little extra glue or sanding, respectively, can fix.

Match sanding fins is NOT nearly as easy for me to correct (I really need to invest in a bench sander!) and it's easier to tell if one/some of them are off/not the same size where as CRs are generally internal parts...

Just another $0.02...
cnc just means a machine that is computer controlled.. you can make bad fitting rings with a cnc router just as quick as a drill press or a laser cutter, if you don't set it up right.. so saying that the rings are cnc cut really doesn't have much bearing on the final product. what the person recieves in the mailbox is what matters.
If you want to advertise custom work, such as fins or special rings cut to the customers spec from cad drawings or mabey a rocksim file(like BMS), than it would be an advantage for people to know that you have that capability.
I personally believe it does not matter. As long as it fits! Our rings probably fit better then most because they are cut with a hole saw and then sanded to perfect diameter. This also gives them an easy fit because the edges are very smooth and a bit curved so they it will slide in easily. I will post pictures soon that show how nice they look!
Ah shucks! This wasn't going as planned. Well, thank you all for your inputs!