How does one cut the perfect body tube section???

[scottluther1369]

How does one cut the perfect body tube section??? No mater what I do I'm off by just a tiny bit. Is there a jig I can make to make them come out perfectly round?
Thanks!!!!
--Scott<The newb ie>

 

[sandman]

I made one of these and it works pretty good.

https://www.info-central.org/index.cgi?construction

You do need a mandrel (something heavy inside the tube to hold it up against the cutting blade). A tube coupler works but not very good!

For cutting BT-5's, BT-20's, BT-50's, and 29mm motor tubes a spent motor casing works perfectly.

For odder sizes like a BT-55 or BT-60 I make wooden mandrels that fit lightly inside the tube being cut.

Did that make any sense?

Can someone else explain it better?

My inglesh she not so pretty good.

 

[Hospital_Rocket]

I found a bandsaw and miter jig the absolutely perfect solution to this.

At $69 a bit expensive, but I can use the bandsaw for other uses as well.

 

[raw9jr]

I'll also vouch for the jig Sandman refers to.

Works great.

 

[Stymye]

probably not the best option for everyone, but this is my weapon of choice.. cuts 1/4" to 4" razor perfect.

 

[sandman]

The jig only costs...maybe a few bucks to make.

Miter saw is a tad rough on BT-50's and smaller.

I have to totally agree on the band saw!

Try cutting 3"x3" balsa blocks for turning on anything OTHER than a band saw. A band saw does very smooth clean cuts in balsa.

Mine was $69 too really old...its from "Builder's Square"! The band saw is my #1 power tool for rockets!

 

[Stymye]

definately the jig is a great little tool...
I only use the miter saw because I have one

 

[wwattles]

I use that jig as well, and built it from "salvage scrap" at the local home warehouse store. Total cost: $2.68.

It cuts like a hot knife through a hunk of really soft stuff...

WW

 

[DumasBro2]

I use that jig as well. It seems to work better on larger tubes though. For smaller tube I will cut them aon a band saw and square the end up on a disk sander.

steve

 

[vjp]

For cutting Estes-style body tubes, the only method I have ever used is this.

Cut a piece of cardstock about 1"-2" wide, and long enough to wrap around the tube plus a little over-wrap. Tape the piece tightly around the tube so the ends of the straight edge are lined up perfectly.

Stick a piece of tape over the non-cutting edge to keep the guide from sliding around, and use the straight edge to guide your x-acto blade around the tube. Make a couple of very light passes at first, to establish a straight cutting line, then cut the rest of the way through.

Makes very straight cuts and no jigs needed.

 

[Micromeister]

Whichever jig you build, buy or use if you don't use an internal mandrel of some kind you WILL get a ratty ragged or deformed edge.
Heres my tube cutter build entirely from scrap alum. angles and bar. and about 8 screws. I can cut up to BT-101 with a perfect edge (just like the factory edge) up to 18" or cut off as little as 1/4" of a 36" tube. Internal mandrels are the difference between a perfect cut and hacking them off with an xacto or razor blade. In case you wondering I got this info from Euclid, the folks who make and supply estes tubes. They use hard rubber mandrels mind you but the effect is identical

 

[cls]

I thought everyone did it this way:

start with a (2'?) length of wood corner mold. cut one short piece to use as a stopper, screwed a razor blade to the end of the long piece.

the short piece is clamped by a binder clip to the long piece, at the right distance from the razor blade.

hold the tube in the V of the mold with the end against the short piece, press lightly on to the razor blade, and spin it around a few times. works fine from BT5 up to BT80.

hmmm, maybe I should post a picture.


for larger tubes like 5" to 10", I've used a large hose clamp to mark the line and make a rest, then put an xacto knife or razor blade on the tube ... turn many times, cutting lightly.


wow, lots of interesting ideas here. I will try the miter and bandsaw later today. but, doesn't it leave a ragged edge? what bandsaw blade do you use?

 

[DJ Delorie]

Am I the only one who uses a lathe? I've turned cones for both centers, mount the tube between them, spin it up, and hit it with a fresh xacto blade. The cuts are perfectly square to the tube and clean.

 

[Stones]

Originally posted by DJ Delorie
Am I the only one who uses a lathe? ...

Not after this posting. Great idea! Just need to make up the cone for the chuck and I'm all set.

 

[edwardw]

I also use a compound sliding mitre saw. I use it because I have one. Works great.

Edward

 

[11bravo]

I recently used this-

https://pg.photos.yahoo.com/ph/gps_greg/detail?.dir=284f&.dnm=26f0.jpg&.src=ph

to cut a non-brittle phenolic tube.
Worked surprising well.
One uses the tools one has available.

Greg

 

[DynaSoar]

Originally posted by scottluther1369
How does one cut the perfect body tube section??? No mater what I do I'm off by just a tiny bit. Is there a jig I can make to make them come out perfectly round?
Thanks!!!!
--Scott<The newb ie>

I use masking tape. I get one go-round of that perfect on one edge first. If it's not, I pull it up and do it again. Once it is I give another wrap or two over it. Then I use the edge of the tape to cut against. Once around with the Xacto to make the line, then around and around with the razor saw. Until the very last cut-though. I go back to the Xacto for that because the inside of the tubes tend to shred a bit.

 

[Micromeister]

Before I made my tube cutting jig I used Screw tightened automotive Hose Clamps. Tighten just enough to give a easy, self leveling cutting line for tubes BT-5 to 5" od. Above 5" I've never gone so your on you own for the super thick wall stuff. I seem to remember I used 3 or 4 sizes of these Hose Clamps to cover the whole range of estes type .013 and .021 wall cardboard tubes. Stainless steel banding will give you a decent level cutting line but does nothing about tearing up the inside of the tube while cutting, even with a brand new single edge razor blade...ya still should use an internal dowel or whatever mandrel(s) to get the Perfect Cut

Masking tape is a nice guide if its applied over a drawn line, super inaccrate for simple tube cutting, as it stretches badly with the lightest pressure. If you feel tape is your best choice at least use one with very little stretch like magic tape or adhesive backed stripping tape (at least 1" wide). Masing tape is useful for cutting odd shapes and tapered pods where you need some give in the line. .

 

[DynaSoar]

Originally posted by Micromeister
Masking tape is a nice guide if its applied over a drawn line, super inaccrate for simple tube cutting, as it stretches badly with the lightest pressure. If you feel tape is your best choice at least use one with very little stretch like magic tape or adhesive backed stripping tape (at least 1" wide). Masing tape is useful for cutting odd shapes and tapered pods where you need some give in the line. .

Yep yep, I shoulda said, thanks.

Got to start with a drawn line. And since masking tape can slip, you can use that to advantage. If you're within about 1mm of the line, you can usually slide it along the tube that amount up to the line.

I'm liking the hose clamp idea. I'll have to get some.

 

[sandman]

Oh! I forgot to mention one very important tool when cutting tubes.

Sometimes...even the best of us...we use a mandrel, use a fresh blade...we still mess up...a bit.

For those not so perfect cuts make a sanding block with 100 grit sandpaper, some contact cement, and a flat piece of wood.

Sand your not-so-perfect edge with a circular motion going around the edge evenly to fix it.

 

[DynaSoar]

Originally posted by sandman
Oh! I forgot to mention one very important tool when cutting tubes.

Sometimes...even the best of us...we use a mandrel, use a fresh blade...we still mess up...a bit.

For those not so perfect cuts make a sanding block with 100 grit sandpaper, some contact cement, and a flat piece of wood.

Sand your not-so-perfect edge with a circular motion going around the edge evenly to fix it.

Definitely. And I often put a ring of thin CyA on it first to stiffen it so it sands evenly.