How to drill holes in a cardboard altimeter bay?

[George Lynn Paul]

I didn't have much trouble drilling holes in my first dual deploy altimeter bay. It was fiberglass. But now, I am trying to drill holes in a Loc Precision 4-inch rocket altimeter bay. The altimeter bay has a very thick, heavy-duty "stiffy" inside. Then outside that is somewhat thinner "coupler." Then outside that is a body tube, in this instance a 1-inch "switch band." So I need to drill through 3 layers of paper type materials -- and make an elegant, precisely shaped hole. How does one best do that? Thanks in advance for your wisdom and thoughts.

 

[Buckeye]

The vent holes do not need to be perfect to function. Harden the holes with CA then sandpaper and a rat tail file to sand off the fuzziness and smooth the holes.

 

[fyrwrxz]

Back up the interior coupler. Drill spot 1 size smaller than the final dia. the outside with minimal pressure. Keep up the speed so the drill flutes don't grab. Drop in a spot of ca and let cure. Contunue drilling and backing out. Let the drill do the work, dont push. Add more ca. Once you punch thru the backside, remove your backing. Add more ca. Finish driiling full size and ca the hole. Sand flush both sides. Perfect holes!

 

[George Lynn Paul]

The vent holes do not need to be perfect to function. Harden the holes with CA then sandpaper and a rat tail file to sand off the fuzziness and smooth the holes.

Thanks much. Getting the idea. I need to pick up some of those small files. Appreciated!

 

[George Lynn Paul]

Back up the interior coupler. Drill spot 1 size smaller than the final dia. the outside with minimal pressure. Keep up the speed so the drill flutes don't grab. Drop in a spot of ca and let cure. Contunue drilling and backing out. Let the drill do the work, dont push. Add more ca. Once you punch thru the backside, remove your backing. Add more ca. Finish driiling full size and ca the hole. Sand flush both sides. Perfect holes!

Thanks. This is quite detailed and very helpful. Once again, I am reminded that there is a great deal of craftsmanship in building a large rocket!

 

[David Schwantz]

brass tubing. Sharpen the inside and use a backing block on the inside of the tube, Thee holes wil be perfect.

 

[Scott_650]

Guess I’m ok with a hole punch I found in my desk drawer - not even sure where it came from - or just picking a random drill bit and zapping in the hole with my cordless drill. I do seal the edges with CA and touch up the paint with a close enough color Sharpie.

 

[dr wogz]

'spur drill bits' or wood or brad point bits..

they have points at the extremes of the flutes/ point. Kinda cuts / carves the OD of the hole before the middle part punch & tears thru.. Not a Forstner bit.. or a flush cutting hole bit..

(scroll down a bit)
https://www.diydata.com/tool/drillbits/drillbits.php

 

[manixFan]

Regardless of method used to make the hole, having a backer seems to be critical to success. I've probably used all the methods mentioned and I always regret it when I get in a hurry and don't back the hole with a piece of wood or scrap coupler. The brass tubing method works well for thin body tubes, but for thicker ones a sharp bit works well. Dull bits can pull up the paper, at least in my experience.


Tony

 

[Dane Ronnow]

brass tubing. Sharpen the inside and use a backing block on the inside of the tube, Thee holes wil be perfect.

Sweet! I was looking for a punch solution (as opposed to drilling) for altimeter vent holes, but didn't want to buy a punch. Thank you, sir!

 

[David Schwantz]

anytime

 

[George Lynn Paul]

'spur drill bits' or wood or brad point bits..

they have points at the extremes of the flutes/ point. Kinda cuts / carves the OD of the hole before the middle part punch & tears thru.. Not a Forstner bit.. or a flush cutting hole bit..

(scroll down a bit)
https://www.diydata.com/tool/drillbits/drillbits.php

Thanks. This is helpful in the extreme. That article is a huge resource. I need to print that out.

 

[George Lynn Paul]

Regardless of method used to make the hole, having a backer seems to be critical to success. I've probably used all the methods mentioned and I always regret it when I get in a hurry and don't back the hole with a piece of wood or scrap coupler. The brass tubing method works well for thin body tubes, but for thicker ones a sharp bit works well. Dull bits can pull up the paper, at least in my experience.


Tony

Thanks much. This has been a helpful post. I appreciate your help!