One of the easiest ways to cut sheet 4130 is with a band saw. Use an
old metal cutting blade installed upside down (the teeth pointing up).
Run the saw at normal speed and feed in the material. Keep the
pressure up and it will go (melt) through like you are cutting butter.
Don't pause though, it is not so easy to get started again. Some have
also used the back side of the blade for this purpose with success.

O-ring Seals

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Dear O-ring (and the Group),

I believe you'll find there's a bit more to it than that :-)

First off, the 'normal speed' you're referring to is for a woodworking bandsaw.
The down-side is that most woodworking bandsaws are fitted with a rubber
'tire' on their driver- & idler-wheels. Friction cutting steel (which is what
you're doing) will destroy the tire on the driver-wheel in short order.
Bandsaw tires are moderately expensive and can be hellishly difficult to
replace on some saws.

Metal-cutting bandsaws do not use tires. The wheels are sizes so that the
teeth overhang the edge of the wheel, not only for cooling but for clearing the
swarf.

You can set-up a metal cutting bandsaw for friction cutting if you have the
proper ratio pulleys (ie, increase the blade speed).

The popularity of this method hinged largely on the builder's ability to splice
their own blades because the original idea was to use common steel strapping.
Operated at high speed -- and cutting relatively thin stock -- the stuff does
in fact cut like butter, with a very attractive displace of sparks, too :-)
But the strapping was rapidly consumed and unless you were a dab hand at
splicing, ideally with a Do-All type butt-welder, there was no long-term
advantage over regular cutting.

All of this came about due to the difficulty of cutting relatively hard steel
in thinner gauges, which loves to strip the teeth off anything. .035 4130, you
can do pretty well using a regular bi-metallic 32T blade by simply rigging the
work to feed 'downhill' so that two teeth are in contact with the work.

I've responded to your message because it appeared to be addressed to me, even
though I was not the person who posted the original question. Someone else has
already offered the most practical solution, which is to track down a
stomp-shear and just whack those puppies out. But the fellow posting the
question implied he not only wanted to make the part but that he wanted to
acquire the tool, learn to use it, and make the parts himself. In that light I
thought telling him to buy a shear might be a bit much :-) ...but did mention
several other methods & tools for producing the parts. I think I even
mentioned bandsawing but I assumed he would know I meant with a metal-cutting
bandsaw.

Friction cutting is kind of fun but if your only means of splicing a blade is
to taper the piece and use hard solder, I think you'll find you can't use
strapping. Too thin; the splice fails due to the heat. And if you can't use
strapping I don't see much sense in ruining a good blade, unless you're trying
to cut 6xxx stock or a leaf spring or something like that and friction cutting
is your only option. Personally, I'd just whip out my phasor, give them
Klingons hell :-)

-R.S.Hoover