Profile cutting tools

Fish30114 said:
Heck JT, you've got me mostly sold on a plasma cutter--I watched several videos on YouTube earlier, and it looks pretty understandable to me--not really sure of how to make sure my compressor air is really dry--need to study up on that a bit--I have thought about getting some of my patterns water jetted but I make a lot of one offs, and I like being able to efficiently profile my blades myself.

Look forward to any more input.
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They make inline dryers to put just after your air compressor, but a dedicated system can easily cost at least as much, if not multiple times the cost of your compressor. If I'm not mistaken, some of the compressor companies make smaller (and cheaper) dessicant style filters, and I think I've even seen a couple of home brew set-ups in the $100 to $200 dollar range that you change a filter on every month or so.
Probably a small price to pay to keep from ruining a $1500+ machine I suppose.
 
JTknives said:
That's funny right there, made my day.
I have thought about building a pentagraph that holds the torch and I can trace the template with a little probe. Would make cutting much smoother to trace templates.
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That's a heck of an idea.
 
wkfl said:
Is this plasma cutter ok for all steels?
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Yes !!
Actually, Anything metallic cuts with plasma.
You can even cut some ceramics & glass if you layer it between metallic sheet.

Its almost too fast. The instant you press the trigger, its cutting. Your start must be spot-on or you may have a blemish on your workpiece.
 
I roughly cut out my blanks with my bandsaw and then profile on a contact wheel with a workrest. I only use old ceramic belts and at full speed you can make short work of it. Profiling is the easy part for me. What I hate is removing the mill scale. I really want a surface grinder.
 
Lieblad said:
Yes !!
Actually, Anything metallic cuts with plasma.
You can even cut some ceramics & glass if you layer it between metallic sheet.

Its almost too fast. The instant you press the trigger, its cutting. Your start must be spot-on or you may have a blemish on your workpiece.
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Start away from your finished edge and lead in to it. Piercing is the worst for this and will always create a hole wider than the plasma kerf.
 
My hypertherm has about a 1/4" offset when bumped up against a 1/8" template. So I could make a template that is all around 1/8" smaller than the finished dimensions or cut a negative template that is 3/8" larger. Maybe for different knife shapes one would work better than the other. This would leave about 1/8 of material to grind off to grind away any heat affected zone.

If I was doing the same blade over and over again I would to that. 1/8" mild steel template cut to account for whatever your delta is between running the plasma tip against the template +/- 1/8 to account for any HAZ and the plasma jet. Glue it onto your steel with a drop or two of CA glue and buzz those babies out. Maybe make several templates and plasma out 5 blanks at a time or whatever. Or, depending on the thickness of the steel you could probably stack 2-3 stacks of material and cut multiple blanks out under each template with one pass.

For me it doesn't make sense as I don't do multiples of the same thing.
 
Oh and I have the Air30 that has a dryer and compressor built right into the unit. You lose a little oomph by not having it hooked up to a large compressor but I haven't felt deprived. Heck, I even mostly run it off of a 20A 115V circuit as it's a pain to switch out my 220 Grinder with the 220 plasma cutter plug.

I think a couple brands now have their smaller units with compressors built right in.
 
i appreciate the info. i had not considered that. maybe a higher blade speed would cut more quickly ? i am running it @ 107 sfpm. i can go up to 196 sfpm and have slower options for 78,57 & 30 sfpm. thank you.
kuraki said:
10 TPI for cutting profiles will be a mistake. That's .100" between teeth. The rule of thumb in bandsaw cutting is 3 teeth engaged with the work. You would only engage 3 teeth simultaneously when cutting .300" or greater material. 14 TPI can work but even that is a bit coarse and will mostly have 2 teeth engaged. 20 TPI is pretty ideal.

If 14 is working for you without losing teeth, I would stick with that. A 10 TPI blade in thin steel is going to knock teeth off quickly, and once it starts on a band it propagates quickly.
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In general I would say yes, you can run a bit faster. It will depend on the steel and the condition it's in but if you are mindful of heat buildup you can increase the speed.
 
knife to a gunfight said:
FWIW, you can cut most knife making related profiles on a porta-band, you just have to get creative. A 1/2" blade can't cut a very tight radii, but if you cut a series of "relief cuts" you can get into much tighter corners and such. You may not stay right up against your line, but you can still remove enough material to make cleanup on the grinder much quicker and easier.
For certain profiles and radii, I sometimes will pre-drill or even use an end mill or a hole saw to remove material. It really just depends on what your cutting, and what kind of material and real estate you have to work with.


Is it as efficient as a plasma cutter? No. But if you don't have $1500+ to spend, it's an option.
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Metal cutting bandsaw is still king for me, you can cut any shape including curves. You have to make slices and small cuts but it is easy once you do it a couple times and have the right blades.

Waterjet is the easiest and not that costly, for folders it causes issues with action because of the kerf and tolerances but for fixed blades it's fine.
 
Pittknife, I am searching for an easier than port-a-band profiling cutter--water jet is extremely costly AFAIK to own yourself--getting a handful of patterns cut out, I think there are lots of options for that, but quickly and efficiently profiling individual blades for oneself it seems that the plasma cutter might be the best option, within a reasonable cost envelope. I have a port-a-band on a SWAG table and I have been having issues with it as of late--and this and the apparent simple effectiveness of the plasma cutter as an example got me looking for these options.
 
JT have you used your plaz on thicker material? I'm getting one and really want the duel voltage. The older low power plasma cutters I have used in the past start to fall off fast around a 1/4". I was planning on something in the 50-65 amp range.

Plasma cutters will cut anything that will conduct electricity. The concept is basically the same as a TIG Welder except that the gas is fed in through a venturi and it doubles the arc temperature bring it up to 40,000 deg Fred. I don't think anything can take that heat.
 
Mine cuts 1/4" great, not super fast but fast enough for my needs. If I was cutting 1/4" and up all the time I would bump up to the powermax 45 but I love the dule voltage on the 30. I will head out to the shop in a few min and shoot a vid showing what mine does and what you can expect.
 
Have any of you guys used wire EDM? It seems to me that of the "hot" methods, it leaves the smallest HEZ and an edge finished that puts everything else shame. The kerf AND the rough edges is what bothers me with water jet.
 
jdm61 said:
Have any of you guys used wire EDM? It seems to me that of the "hot" methods, it leaves the smallest HEZ and an edge finished that puts everything else shame. The kerf AND the rough edges is what bothers me with water jet.
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EDM works great if you have unlimited time and a bags of money to buy it.
But since we are doing EDM, might as well start off with hardened, tempered steel & just carve that into finished blades !!
 
I use to run a EDM to cut slincer cores out of Titanimum. It's a sweet machine but cuts WAY slow , measured in Inches per hr but that varies depending on material thickness. You also have to buy spools of brass wire that are rather pricy at around $100. You will burn through this in a few days to a week of run time. EDM is one of thoes machines used for things that require very tight tolerances and where price does not really matter.
 
The best use any of us could put an EDM to would be cutting guard holes to cut a perfect press fit without ever touching a file.
 
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