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winding a paper core - making a centre on which to wind it

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JerryNotts:
I want to be able to wind some 'cardboard' cores on which to wind some paper.

Those members with roll-fed labelling machines or who have worked in the paper and board industry will know immediately what I mean. Most tiolet rolls have a core.

I imagine a bar (brass or steel?) between centres on the lathe with a number of sectors fixed ( but adjustable diameter ) to the outer diameter but I am really lost on this!

The sizes I want to make are between 20 and 50 mm ID and up to 100 mm long.

I can make an anilx roller to apply the glue and cones on the take up roller.

Any guidance please.

Jerry

BillTodd:
you'll probably need a collapsible mandrel - three or four segments on a tapered core  if you can arrange the control of the core with a collet closer lever it could be single sided

while a lthe will work , you might want better control over speed , especially if hand feeding the paper.

I've built specialist winders for copper coils ( 100mm wide 1.5mm thick) and found the best way to tension was with pinch rollers , although 6ou may get away with one roller with card or paper.

JerryNotts:
I've now spent some time looking at the potential difficulties in this task. Perhaps I should have done this before posing the original question.

I have looked at both the main products of the paper core business, square paper tubes and spiral wound tubes, taking some account of the facilities I have, especially space.

On the face of it square paper tubes are the simplest when small scale maual methods are considered, since a frame using two rollers with nip adjustment and an operator who can acquire the skill to apply an adhesive controllably are all that is needed.

Making spiral cores, except on an ad hoc basis, requires much more thought but, in conversations with ex-colleagues with who have experience can yield consistent results and if needed high production rates.

A problem which the uninitiated often apparently expereince is the diffficulty of removing the wound core from the mandrel. On occasion when making square cores it has been necessary to destroy the core in order to recover the mandrel. This is less of a problem in industrial  scale production as the paper tension or the nip pressure on the machine can be controlled as can the condition of the mandrel. The simplicity of a manual technique appeals to me because of its simplicity. Do I have the concentration to make about 50 cores without making mistakes?
As Bill Todd mentioned in his reply I haveexamined the idea of a collapsible mandrel.  I am told this should not be necessary (I'm looking forward to proving this). It seems that with the correct adhesive, tension, nip pressure and attention to the condition of the mandrel that a core can be wound which needs minimal force to remove. First picture from the tube gives an idea and in the actual video he manages to remove the mandrel without brute force.

Making a spiral winding machine is much more challenging. I intend to spend some time drawing out how this might be done. Watch this space but don't hold your breath.  See the second attached picture from UT for the drive mechanism of this sort of machine. The mandrel in these machines does not rotate but the constant polishing of the paper against the steel keeps it in good slippery condition. Industrial machines need some considerable power to drive the belt rolls, typiccally 40-50 HP depending on the number of plies being combined,

BillTodd:
I've just finished a spiral winder , on a somewhat different scale to the one in your picture , I had to deal with +/-1um tolerances and one dimension spec'd at 3.2um . Amazingly, there are parts of the above paper coil winder that are strangely familiar  :D

JerryNotts:
i''m sorry Bill I am not sure which parts you mean, or which winder.

Jerry

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