Drilling standard size rocket holes

Anyone know of a way to drill standard size holes (ie: 18mm, 24mm, 29mm, etc) in materials? I want to get some balsa drilled to fit an 18mm MMT but I can't find anyone willing to do custom work on very small scale (two holes total) and capable of providing me what I need.

I found drill bits on Amazon for 18mm and 24mm (29mm is really close to 1 1/8"). Bit pricey for infrequent uses but an option nonetheless.

Anyone have some insight on this?

You might try taking it to a cabinet shop and asking then to drill the holes with a forstner bit. Try going undersized first as balsa is soft and may tear out away from your intended dims. Using a small rotary drum sander helps with this.

Performance nut said:

Anyone know of a way to drill standard size holes (ie: 18mm, 24mm, 29mm, etc) in materials? I want to get some balsa drilled to fit an 18mm MMT but I can't find anyone willing to do custom work on very small scale (two holes total) and capable of providing me what I need.

I found drill bits on Amazon for 18mm and 24mm (29mm is really close to 1 1/8"). Bit pricey for infrequent uses but an option nonetheless.

Anyone have some insight on this?

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What exactly are you trying to make?

Try this instead of drilling if you need to do something in balsa:
https://georgesrockets.com/Articles/CentRings/Rings.htm

kj

kjohnson said:

Try this instead of drilling if you need to do something in balsa:
https://georgesrockets.com/Articles/CentRings/Rings.htm

kj

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That is a very clever way to make centering rings. Thanks for the link.

tmacklin said:

What exactly are you trying to make?

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Take some nose cones and hog them out to make room for 18mm engines. Just need part of the engine inside the nose cone, not the whole thing. BMS has the cones I want but aren't willing to do custom work. Right now, I'm leaning towards plastic nose cones but concerned about ejection charges being too hot and distorting the plastic. I have heard folks using heat resistant paint on plastics to help with high velocity flights, wondering if this will work with ejection charges as well.

kjohnson said:

Try this instead of drilling if you need to do something in balsa:
https://georgesrockets.com/Articles/CentRings/Rings.htm

kj

Click to expand...

This wasn't something I considered doing. Have you done this before? This is not practical for this project but is very useful for something else I'm doing. Just curious about results and how successful it has been used.

Performance nut said:

Take some nose cones and hog them out to make room for 18mm engines. Just need part of the engine inside the nose cone, not the whole thing. BMS has the cones I want but aren't willing to do custom work. Right now, I'm leaning towards plastic nose cones but concerned about ejection charges being too hot and distorting the plastic. I have heard folks using heat resistant paint on plastics to help with high velocity flights, wondering if this will work with ejection charges as well.



This wasn't something I considered doing. Have you done this before? This is not practical for this project but is very useful for something else I'm doing. Just curious about results and how successful it has been used.

Click to expand...

I see. It is pretty tricky drilling into Balsa, especially into the end grain. Also, if you are trying to drill a nose cone that is already formed, it is difficult to secure the workpiece without marring or crushing the surface. If you are making your nose cones from scratch, you can start out with a rectangular block that is oversized, carefully mark the centers on each end and secure it into a dill press vice for the drilling operations. Doing this will mean that any scars created will be removed when shaping the nose. If you also make the block longer than necessary, you can then drill a smaller hole and glue a short section of hardwood dowel into that hole. This will allow you to use your drill press as a vertical axis lathe. It's not ideal but it works with some practice and, it's also a path toward the accumulation of a vast arsenal of tools! :wink:

tmacklin said:

I see. It is pretty tricky drilling into Balsa, especially into the end grain. Also, if you are trying to drill a nose cone that is already formed, it is difficult to secure the workpiece without marring or crushing the surface. If you are making your nose cones from scratch, you can start out with a rectangular block that is oversized, carefully mark the centers on each end and secure it into a dill press vice for the drilling operations. Doing this will mean that any scars created will be removed when shaping the nose. If you also make the block longer than necessary, you can then drill a smaller hole and glue a short section of hardwood dowel into that hole. This will allow you to use your drill press as a vertical axis lathe. It's not ideal but it works with some practice and, it's also a path toward the accumulation of a vast arsenal of tools! :wink:

Click to expand...

And this is probably why no one does custom work

Starting to look like plastic is the way to go on this one.

Performance nut said:

This wasn't something I considered doing. Have you done this before? This is not practical for this project but is very useful for something else I'm doing. Just curious about results and how successful it has been used.

Click to expand...

Yeah totally not going to work with what you are trying to do with nose cones or balsa block.

Yes I've done this with balsa and thin ply for centering rings. Follow the directions and don't try to go all the way through on the one side.

kj

I can do that.

I do it all the time.

PM me

I actually might know the answer to this one! When I'm hollowing out a piece for an 18mm motor mount, I use an 11/16th grinder bit available at most Home Depots for about $3.50. As far as the other sizes, I'd need more info on what you are trying to do.

Drilling motor mount holes out in centering rings is a process of trial, error, and skill development.

My best advice is drill the holes slightly undersized and sand them to fit. I have a collection of hole saws and forstner bits that I use on my benchtop drill press. After the holes have been cut, I use a sanding drum to expand the holes to fit the motor tubing which are not the same diameter as the motors they will hold...the outside diameter of a motor tube for 29mm motors is larger than 29mm. The same goes for all the other sizes as well but the difference varies from size to size.

Good luck with this.

If you'd rather just get the work done, Gordon (sandman) has made you an offer and he's an excellent woodworker/craftsman. Ask him about the strip canoe/dinghy he built.

Try something like this
https://www.irwin.com/tools/drill-bits/drill-press-adjustable-wood-bits
Adjustable size drill bit for wood.
It takes about 10 tries to get the exact size you want but they do work for a hole, not so much for the outer cut on a centering ring. For that try a fly cutter.
And sand paper, lots of sandpaper.

+1 on sanding. I print out the rings from rocksim and glue them to the wood with a glue stick. I use a dremmel sanding drum to get the inside sized and a belt sander for the outside ring. Go slowly and check often.

I was going to suggest contacting Sandman. His work is second to none.

Sandman is definitely awesome.

Another way to go might be to buy a tail cone (which is like a nose cone but cored out for a motor mount tube to go through it, then put a smaller nosecone in the "bottom" of the tailcone (which, now is the top of your assembly). Might take some fitting but it would be doable with off the shelf parts.

Performance nut said:

Anyone know of a way to drill standard size holes (ie: 18mm, 24mm, 29mm, etc) in materials? I want to get some balsa drilled to fit an 18mm MMT but I can't find anyone willing to do custom work on very small scale (two holes total) and capable of providing me what I need.

I found drill bits on Amazon for 18mm and 24mm (29mm is really close to 1 1/8"). Bit pricey for infrequent uses but an option nonetheless.

Anyone have some insight on this?

Click to expand...

Yeap!
I have 13mm, 18mm & 24mm HSS drill bits for drilling in woods and metals but generally when I'm enlarging a hole in a Balsa or Basswood transition or nosecone I use a hogging rotary wood rasp in either an electic Drill or Drill press to get the hole started and finish up with a Dremel drum sander. Inserting Body tubes or couplings centered under a bubble level while the epoxy cures set in a gimbled ball bearing vertical fixture so everything stays plumb. There are also Arch punches in Millimeter sizes for use on plywood, cardstock and other non-metallic materials.

All these tools are on the expensive side but if we are serious about "Precision" in our hobby we have bit the bullet sometimes