@custard.
Thanks for the additional info about your job via PM. Sorry for my ignorance, but I now understand your scratch stock job - "a bit" anyway. (Being a dumbo, I 1st Googled "scratch block" which, apparently, has to do with coded jigsaws or something, nothing at all to do with wood working)!
OK, clear now. I'm lucky that my wife bought me a very nice scroll saw for my 70th, and personally I would use that with a suitable metal cutting blade for this job (you can down load a table of Pegas metal cutting blades from the link in my hack sawing piece - just under Photo 28). Pegas (amongst others) have blades tough enough and fine enough to cut your stuff OK. Then add a zero clearance insert to the machine and off you go.
If you don't have a scroll saw (it doesn't need to be a posh one, but MUST cut pretty slowly) then instead you could use the same blade in a Jewellers/Piercing saw frame if you've got one (the lower frame shown in Photo 14 - I think the other two frames shown in that photo probably wouldn't tension the blade well enough).
Otherwise I see only 2 choices, because neither the Goscut tool nor the Nibbler tool referred to in my post will, I think, do the job. At about Rockwell 50 your stock is a bit too hard/tough for both probably. So your 2 remaining choices I see are:
A thin cut off disc in a small drill: You don't need an expensive one - I've seen cheapos in Aldi or Lidl from time to time, and although my Workzone (Aldi) sounds a bit rough compared to my Dremel, it'll still do the job fine, OR;
A hacksaw with a 32 TPI blade: If going this route use an all-hard blade if possible, and set the job up horizontally, (flat) on the bench, not vertically in the vice.
If going the scroll saw or jeweller's saw route I don't think a "sandwich support" will be necessary (see below -PROVIDED the job is well supported below - hence zero clearance insert). 30 thou is not all that that thin in this regard. For lubrication ('cos I do NOT want "oil" all over my scroll saw!) I'd use a smear of Vaseline along each cut line.
But if you go either the cut off disc or the hacksaw route, then you'll need to set up a "cutting sandwich". Stale bread might do (!) but a piece of thin ply (up to say about an eighth inch thick, by no means critical, but STIFF) would be better - or even a scrap of thin mild steel or anything else you have to hand that's nice and stiff and not too thick.
Just as CHJ suggested in his previous post, the trick is to make a complete sandwich with a piece of support material under the job, plus another piece covering the top of the job. Do not use double sticky tape or similar between the laminations (it's too spongy). Just mark the job out on the outer face of the top lamination, then wrap the whole lot up TIGHTLY with transparent parcel tape. AND, as you cut each line, replace each of the now broken tape lines with another piece of tape top/bottom/over the cut before moving on to the next cut line. This will keep the whole assembly rigid without anything flapping in the breeze as you cut.
Lubrication is not necessary here IMO - cutting speed will be slow because you can't rush such a cut free hand, and anyway the lamination support pieces will act as a heat sink.
After the last cut, separate the sandwich - use a thin sharp knife and do NOT be tempted to lever the sandwich apart, otherwise you risk buckling the job.
You MAY have a very slight whiskery burr on the lower edge of each cut line, but this is easily removed by holding the job flat in your hand and gently applying a small smooth file, laying it ALMOST flat on the face of the job and gently stroking.
IF the cut line faces need a really fine finish before you file the profile/s into them, then set the job up in the vice (as low as possible) and use a smooth file in the draw filing method shown at Photo 27 in the files & filing post. Use chalk rubbed into the file teeth if necessary.
I don't know how often this job occurs in your shop custard, but I assume it's just "now and then". If so either/any of the above (two, or total four!) options should work without investing in anything more than scroll saw or hacksaw blades.
But if it's a "once a week job" (or more) then in your place I think I'd invest in something better - perhaps a sliding holder for a Dremel-size drill (or even a small angle grinder) to ensure dead straight lines with the cut off disc. A small thin cut off disc will definitely cut that stock - just don't let it get too hot.
I can't recommend specific angle grinder "holders" but if you follow the 1st link you'll find loads of pix of metal cutting stuff (in some cases they look big enough to cut up bits of scrap battleship)!
The 2nd link will take you to many pix, a few of which may ring a bell if you're considering the Dremel-size tools option. These include a couple of DIY holders that look easy to make. Again I can't recommend any specific products/plans because the bit of sheet cutting I do with cut off disc I do with a hand-held Dremel (or clone).
1st link:
https://www.google.ch/search?q=abrasive ... IqyJIook1M:
2nd link:
https://www.google.ch/search?q=mini+dri ... 93&bih=498
HTH.
But I stress I'm no expert and there are many other members with knowledge and experience, so it could well be that someone else will come up with better ideas.
Good luck.
AES