Tube rolling help

[lloyd]

"I was using very thin paper, so maybe with thicker paper this could be a problem. "

----------

Baldor, thank you! I was tempted to make a comment about just that. But in light of the 'abrasive' attitude I'm presumed to have, I thought it would be better to let it alone.

 

With thick (or multi-ply) papers, tearing out that turn might interfere with tooling fit. Of course, with thin paper, one turn shouldn't matter much.

 

You said exactly what I was thinking! Thank you!

 

Lloyd

Edited July 10, 2017 by lloyd

[insutama]

That makes sence ill try rolling some 30lb kraft tubes.

[Baldor]

No need to thank, Lloyd. And for my part, don't worry about "abrasive" comments. I prefer abrasive good advise than missing something important.

[Baldor]

That makes sence ill try rolling some 30lb kraft tubes.

Concentrate in getting a good mandrel. I said you can roll with anything with enough wax, but if you start with a good tool, all the process will be easier, and you only need to make the tool once. If you have an straight and polished mandrel, and if you wax it (solid wax, parafin, or maybe some ptfe dry lube spray) , you can apply glue from the first turn, and still remove the tube. You can even get away with glue in the mandrel, depending what kind of glue you are using.

 

I'm using simple 12mm steel tube, not calibrated, always clean, oiled when not in use, and use a little very fine sandpaper when I see some imperfection. Whit this tool I didn´t have a single delaminated tube. Next ones will need to be turned, since 15 and 19mm (seems are standars sizes for rocket tubes in Europe) are not standard stock. (But perfect for make god mandrels from 16 and 20mm stock)

[insutama]

how about ABS piping ? you can get lots of different sizes

[dagabu]

Abs and PVC piping are both ejected through a die and can change Dimensions inside and outside several thousands in just an inch or two. I would be very careful about using either one of those four-dimensional purposes.

[insutama]

Okay so round bar or piping would be best

[lloyd]

Insutama,

 

PVC is 'piping'. Dave just said it's irregular in dimensions, because it's extrusion-molded, which is generally correct. Good-run Charlottetown PVC is pretty consistent in roundness and o.d., but I wouldn't bet my life on its being exactly the same o.d. over several inches' length.

 

METAL bar or tubing is what you need. 'Pipe' (except for some exotics) is made for plumbing, not for precision.

 

Precision-ground shafting isn't all that expensive, in short lengths.

 

Lloyd

Edited July 11, 2017 by lloyd

[Baldor]

I think you should look for something similar to this. Am I right, Lloid, Dave?

 

I searched for steel tubing, and what I linked is similar to what I'm using. (but mine is not inox, I get it at a brico store, and don´t know exactly what it is, but is not inox for sure.)

[lloyd]

Baldor,

That would probably work fine, and is inexpensive. I, personally, expect tubing (unless it's 'precision ground') to vary in 'circularity' over its length. It's not that the total diameter is not right, but that it's slightly-flattened into an ovoid shape, as-received.

 

If I were doing this, I'd use something like this: http://www.ebay.com/itm/1-2-x-12-Drill-Rod-0-1-Tool-Steel-Precision-Ground-500-Machinist-/152541786423?hash=item238432f137:g:LPkAAMXQCndRf-sS

 

It's "tool steel", not Inox, so it would have to be kept clean and oiled when not in use (although it's not VERY prone to corrosion). But you can be assured it will be of a uniform diameter AND roundness over it's entire length. (except for the sawn ends, which should be carefully filed to remove any cutting burrs).

 

Lloyd

[Baldor]

We are talking about rolling paper for a hobby tubes here. The drying process, how you store it while drying, and any irregularity in pressure while forming it will be more important than the mandrel. The formed tube will be a little flexible, so it will also adapt to the tooling, within reason. As long as the mandrel is reasonably uniform, Is there a justification for a 6x increase in price? And multiply this for different diameters.

 

It's an honest question. I'm in a process of serious retooling after my few, wild and non standard rockets. Seems metric standards for paper tubes are a little odd. Odd diameters, while all the tubes and calibrated stock are usually even. I want to stick to metric, since I can purchase paper tubes in Europe with reasonable shipping if needed. Odd diameters are perfect for machining the tooling, usually you can purchase the next even diameter and turn to your desired diameter without problems. But for finding a good mandrel in an odd diameter without paying a kidney for it it's proving problematic. I'm looking for 15mm and 19mm ID for now. 19mm is 3/4", but in Europe we only use imperial for water and gas pipes.

[lloyd]

Baldor, I agree with all you said. I said "If _I_ were doing this...", not that what you suggested wouldn't work fine for most applications.

 

I don't intend to impose my ideas (improperly taken to be 'dictates'), but to suggest how and why I do things. The end result depends upon a LOT of variables. Your tubing suggestion should work fine.

 

Lloyd

[insutama]

I will try and look locally shipping is way to much for a piece of 12" bar

 

http://www.ebay.ca/itm/Stainless-Round-Bar-Rod-Precision-Ground-316-1-2-498-x-11-1-4-/182651204712?hash=item2a86dc3468:g:yJUAAOSw9OFZNJX-

[Baldor]

So, now I have to visit all the metal warehouses in my zone, and plead to them to sell me a single meter of what I need... I can have a 6m bar or tube for the same that would cost me 1m in ebay.. But I only need 1m XD

[insutama]

lol im in the same boat Baldor

[Baldor]

Yep, Insutama. I was using ebay only as examples about what I was talking. I'm looking localy too, but the only want to sell me the full 6m bar. I need to learn to plead better. :-)

 

One place to look if you go the inox tube way, is at an aluminium windows workshop. (Sorry, i'm not sure of the right expresion in english)

[lloyd]

Baldor,

 

So far as cost -- yeah, that's a 'factor'. But consider that ONE good tool will last the rest of your pyro career. Eh... 'one time expenses' (especially when this small) don't bother me nearly as much as recurring ones!

 

Lloyd

[Baldor]

Baldor, I agree with all you said. I said "If _I_ were doing this...", not that what you suggested wouldn't work fine for most applications.

 

I don't intend to impose my ideas (improperly taken to be 'dictates'), but to suggest how and why I do things. The end result depends upon a LOT of variables. Your tubing suggestion should work fine.

 

Lloyd

 

 

Sorry if I sounded like I was criticising your suggestion, it was not my intention. There is a language barrier, English is not my first, not my second language, so some times I have some difficulties making others understand what i mean.

 

I had seen a suggestion from somebody a lot more experienced than me, and seen a great difference in price for what I perceived as a very little benefit, so I exposed the advantages and disadvantages I had seen, and asked, or tried to ask if I was missing something. I will always assume that I'm missing something, I lack a lot of experience in this field, so please, don't take my (possibly not very well expressed) questions as critics.

[Baldor]

Baldor,

 

So far as cost -- yeah, that's a 'factor'. But consider that ONE good tool will last the rest of your pyro career. Eh... 'one time expenses' (especially when this small) don't bother me nearly as much as recurring ones!

 

Lloyd

I agree, to a point. As I said, I'm retooling (If I can call that.... All the "old" tools are made from scrap, are less than two months old, not standard sizes, and not suitable for a serious use. I was just wetting my feet, now I'm in for a serious dedication to this) , so if I can choose between two tools good enough for a lifetime, or one tool perfect for a lifetime, now my choose is good enough. In another moment, I'm with you, as long as we stay within reasonable prices. After more than ten years without touching a lathe, I ordered one small one, not a toy, but good enough for what I want (Not only pyro tooling), this is where all the savings from other tools and materials are going.

[lloyd]

Heh! I couldn't LIVE without a lathe! (since 1972, I've always had one)

 

Good on you!

 

Lloyd

[Baldor]

A few tools made with the lathe and it's amortised, more if I must import them from USA. And I miss machining what I design, miss it a lot. As I said in another thread, I have more fun designing, building, testing ant optimising tools, than the actual act of launching the fireworks. So if I save a little here, and a little more there, I can purchase better tools for my lathe now.

 

Returning to the topic at hand... Some time along next week I should finish a prototype for a tube rolling machine. Focus is in the use of readily available materials and typical power tools everyone can have easy access to, so it should work with big tolerances. Also, uniformity and reproductibility of the results. If it's not an absolute disaster, I will make the plans available (Sorry, in metric) Plan is it should work for anything from 10mm ID to 35mm OD.

Edited July 11, 2017 by Baldor

[Col]

Concentrate in getting a good mandrel. I said you can roll with anything with enough wax, but if you start with a good tool, all the process will be easier, and you only need to make the tool once. If you have an straight and polished mandrel, and if you wax it (solid wax, parafin, or maybe some ptfe dry lube spray) , you can apply glue from the first turn, and still remove the tube. You can even get away with glue in the mandrel, depending what kind of glue you are using.

 

I'm using simple 12mm steel tube, not calibrated, always clean, oiled when not in use, and use a little very fine sandpaper when I see some imperfection. Whit this tool I didn´t have a single delaminated tube. Next ones will need to be turned, since 15 and 19mm (seems are standars sizes for rocket tubes in Europe) are not standard stock. (But perfect for make god mandrels from 16 and 20mm stock)

Try ptfe rod turned 0.1mm oversize, nothing sticks to it

[AllisterF]

I know this thread is older, but for those in the US and Canada that are looking for short lengths of raw materials and can't find them locally, check out Grainger (Acklands Grainger in Canada) and see if there is a local branch by you that you can pickup from... They will generally ship whatever you order free to your branch of choice for will call pickup, it can save you a bundle on shipping vs other online sources...

[Col]

Tube rolling mandrels are a one time purchase so its worth spending a little extra having them turned to the perfect size (slightly oversized), nice and straight with no scratches or dings.

[Col]

Some time along next week I should finish a prototype for a tube rolling machine. Focus is in the use of readily available materials and typical power tools everyone can have easy access to, so it should work with big tolerances. Also, uniformity and reproductibility of the results.

 

All you need for a rolling machine is a pillar drill, a saw and maybe a bigger shed once its done

https://youtu.be/_Iv9un4R-jI