cubitron vs blaze vs merit ceramics

Aside from how awesome it was to see a robot grind 2" of metal in like 30 seconds. This made me think how awesome it would be to have a robot in my shop... and how terrifying it would be to slip... :eek:
 
here are some ideas as to why "there doesn't appear to be any consistency from one maker to the next"

1. The SFPM (speed) of the belt.
2. The amount of pressure used when grinding
3. The grinding process (flat platen, slack or contact wheel)
4. The material being ground (ie annealed, low alloy material vs high alloy stainless)
5. The hardness of the material being ground
6. Wet or dry

so a belt that might last me 2 minutes of constant grinding might last a minute for matt and 5 minutes for don.

scott
 
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I have to say I loved using the 947s grinding bevels in hardened 1095, they do see to wear well for me and stay pretty sharp. I have not tried them on my fastest speed yet, only medium. The cut very nice and uniform and the grit doesnt seem to spray me as much as the blaze. I think I might try some 36 grit VSMs for the first 50% of grinding though. Doing it all with the 80 will take too long I think.

Scott thats a great list there every one needs to evaluate for themselves.
 
timos- said:
I think I might try some 36 grit VSMs for the first 50% of grinding though. Doing it all with the 80 will take too long I think.
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I have used a lot of the VSM in 36 grit, they are great and really excell when dealing with micarta and G10.

They are good for steel, but I have started using the 947a 40 grit for blades and they last longer, cut cooler and throw much less grit.
 
roger that, im picking up some 947a 40grit for the rough stuff and got some of the low grit VSM for taking handle material to size. looks like ill be all stocked up to finish some 30 odd knives by christmas :)
 
On a side note, with my 947a 80 grit, It took 2 belts to 90% grind a 180mm x 38mm chef out of .140 thick w2 hardened to rc63. Does that sound excessive?
 
timos- said:
On a side note, with my 947a 80 grit, It took 2 belts to 90% grind a 180mm x 38mm chef out of .140 thick w2 hardened to rc63. Does that sound excessive?
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impossible to tell. like I said earlier, there are at least 5 or 6 groups of variables that effect belt life, so it make take you 2 and me 3 to do the same job. i guess one way you could check would be to do the next same sized knife with a different brand 80grit belt. How much pre-heat treat grinding are you doing?
scott
 
yeah, I could have prased myself better. I mean would you go guys go through two premiumquality ceramiz 80 grit belts to bang out a 38mm tall by 184mm blade? Im talking full flat grinds to .010 at the edge and a full distal taper.
 
I would use as many belts as was necessary to achieve the end result without heat and loss of control. There's no magic answer as to what is or isn't acceptable belt life expectancy - it's either working for you, or against you!
 
yeah, im just trying to figure out where I can improve belt life, based on others experience. So far its clear i need a water chilled platen, i serrated wheel, a vfd ...the real belt killer though is when you are grinding that 2" wide bevel down to .005, there is a whole heck a lot of friction and only a brand spankin new belt works , for about 10 minutes ;)
 
Man, I made lots of knives without most of the stuff on that list. I think you're overthinking this, bud.

If your platen is running too hot, I'm guessing it's too proud of the wheels. Really only needs to be .030" or so. Pyroceram is your friend!

I agree, a serrated wheel is nifty, but I haven't owned one in years.

Vfd is awesome, and opens a world of possibilities, but not for what you're talking about, I don't think. Fast is efficient with ceramic belts.

You're there, man. Make it work!!!
 
timos- said:
yeah, im just trying to figure out where I can improve belt life, based on others experience. So far its clear i need a water chilled platen, i serrated wheel, a vfd ...the real belt killer though is when you are grinding that 2" wide bevel down to .005, there is a whole heck a lot of friction and only a brand spankin new belt works , for about 10 minutes ;)
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so break up the task. zirc 60 belts work well for metal removal, use them to get your bevel to .020 or .015. now go to a ceramic 80 and take it down to .010. now go to 120, make the scratches go away, thickness to .008. now go to 220, make the scratches go away, thickness to .006. now go to 400, make scratches go away, thickness to .005.
of all the things listed, a slow 3 phase motor, several drive wheels, and VFD would have most effect. get belt speed below 450fpm and you have improved belt life, can run a wet belt without wearing a raincoat, and can grind without making sparks.
scott
 
I have only a little 1x30" and up to now limited experience on belts, but I can already see that the blue Klingspor belts last much, much shorter than Blaze or Sait 7S.

In general - I have not seen Sait belts mentioned here. Any experience on them? I should be adding a 2hp 2x72" later this year and Sait belts can be found in EU.
 
I use the 40-50 grit blaze belts and can grind a 7"-8" chef knife at 2" tall with one belt and it still cuts well at the end. I hope this helps. The blaze belts have always seems better for me.
timos- said:
yeah, I could have prased myself better. I mean would you go guys go through two premiumquality ceramiz 80 grit belts to bang out a 38mm tall by 184mm blade? Im talking full flat grinds to .010 at the edge and a full distal taper.
Click to expand...
 
Do you guys use anything to fracture the grit on the cubitrons?
 
Matthew Gregory said:
Man, I made lots of knives without most of the stuff on that list. I think you're overthinking this, bud.

If your platen is running too hot, I'm guessing it's too proud of the wheels. Really only needs to be .030" or so. Pyroceram is your friend!

I agree, a serrated wheel is nifty, but I haven't owned one in years.

Vfd is awesome, and opens a world of possibilities, but not for what you're talking about, I don't think. Fast is efficient with ceramic belts.

You're there, man. Make it work!!!
Click to expand...

Yes my platen is closer to an 1/8" proud I think. Its not when I used my radius platen but the flat platen is! I didnt notice the difference. That may be my problem then, that the heat is killing my belts. I just used 30$ worth of ceramics to go from .140 thick to .03 behind the edge FFG on a 10" x 2" blade.
 
timos- said:
Do you guys use anything to fracture the grit on the cubitrons?
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More pressure. It takes pressure to get them alive again.

I have an old O1 Platen at 60c I use when I feel the belt not cutting efficiently. Brings it right back to life.
 
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