How to tightly hold a bundle of small steel rods

Im making another pair of these hand carders for SQMBO.
These ones are made from 2mm regular steel TIG welding rods
Attachment 391912

This time I'm using 3mm TSS rods.
Cutting 48 equal length rods is pretty monotonous. They don't need to be a specific length but they should all be the same, so I rough cut them on my thin kerf abrasive table saw and was looking for a way to hold a bundle together to hold them all even at one end so's I could sanded the other end all to the same length.
Tried zip ties - SS was too slippery, Then I tried using a collet in a collect chuck/block.
Get the all levelled up like this

Attachment 391916

And grind the other end on a disc sander like this.
You'll notice one is still short - that's just a spare to help the others sit tight in the collet - its not going to be used in the final pieces.
Attachment 391917

Now have to sharpen one end, bend the sharpened tips, and make up some handles.

if you need to produce a lot of equal lenght rods, fast, you can make your own angle grinder stand with fitting vise, or really just run it through a mounted pipe thats about 10mm off the table/plate you mount it on
we cut up M20 threaded rods for concrete walls that gets epoxied into the ground, and i finally had enough of them breaking the sawblade and occupying out band saw for a whole day cutting out a handful of these rods.
with a thin cutting disc you will go through 10mm rod in seconds, you can just weld some angle iron at the required distance and its quite swift to make your own angle grinder stand, otherwise maybe 20 dollars to buy one, cutting up whole lenghts of metal rods takes me very short time, i dont even clamp it in place, once the cutting disc bites it stays in place, i just keep my left hand on the rod and guide the angle grinder down with right hand with a metal rod sitting in the angle grinder handle to extend it and work against the spring keeping the angle grinder back when i let go

for my device i decided to shape some holeplate to fit my angle grinder, then a nut/bolt open/close mechanism, takes very little time to attach my angle grinder, its ready to go in less than 60 seconds and what would take maybe hours on the bandsaw- and ruining the sawblade in the process takes me maybe 15 minutes