standard diameters for wooden dowelling?

If you can't buy dowel that is the right size, get the next size up, cut it a couple of inches longer than you want, Assuming you don't have access to a lathe, stick it in the chuck of a drill, and use a strip of sandpaper to thin it down.

Or get some the next size down. Roll paper round it until it has grown to the diameter required. (Use glue between layers for super job; a bit of sticky tape at the end for a lash up.)

No need even for a drill. :-)

Take some time:-)

Does it actually need to be round?

regards

Just as a matter of interest, what sort of device is it that you want to run for an extended time, and what is it you are going to use as your external power supply ?

Arfa

You can buy 10 mm dowelling but it usually comes in 1.8M lengths. Try modeling clay of some sort or epoxy putty

Or papier mache

Or a modelling or craft shop, which will have lots of bits of odd-sized wood and plastic in small lengths.

Arfa

Does it need such a specific diameter anyway?

Rob Graham

What about a dead AA or AAA cell - should be about the right size - bit of insulting tape over the ends to prevent it interfering - add the wire as planned

What about a dead AA or AAA cell - should be about the right size - bit of insulting tape over the ends to prevent it interfering - add the wire as planned

'Dead' cell's tend to leak over time and leave a nasty mess not recommended.

Ash

You can buy dummy cells for this very purpose.

Maplin used to keep them, but don't seem to any more. You also used to get them with CB handhelds to make the difference between 10 rechargeable cells at 1.2v, and 8 dry ones at 1.5v. Those ones had contacts and a shorting strap, which would have made them ideal for the job, once the strap had been cut, and wires attached to the two new ends. If there's a CB or amateur radio shop in the area, might be worth just popping in, and seeing if they still have any laying about, long forgotton in a drawer somewhere.

Arfa

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Arfa Daily" saying something like:

A second's googling...

Really? I thought dummy cells were 'short-circuit' - the OP wants to fit a PSU across the 'cell'... :-)

combination of "dummy" and "battery" and "cell" that I could think of into their on-site search engine, and it didn't return any useful results. I hereby declare you king of the keyboard, and authorise you to have an extra cup of coffee and a biscuit for your efforts ... :-)

Arfa

The message from Grimly Curmudgeon contains these words:

nail -- or at least that's what I did years ago when making up an external battery pack for a power-thirsty Z88. For larger sizes of battery, pad out with insulating tape to ensure it stays in location. or use the plastic spacers which allow AA batteries to be substituted for C or D cells