Recommendation? Best tool for heavy stock removal?

C

Charles N

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May 29, 2018
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I've been forging for about 2 and a half years and my biggest enemy has always been getting that last ounce or two of steel off my blade. I was wondering what y'alls best method for heavy stock removal and shaping is, particularly for reducing the thickness. My arsenal includes:

2x72 belt grinder (homemade, 1 HP but it works) My lowest grit is an 80 grit alum. ox.
8in bench wheel grinder (not a beast , will occasionally bog down if i press hard enough)
Files (and a scraper, too)
4.5in angle grinder

I'm also considering buying a 7in angle grinder
 
A stronger motor and a lower grit (good brand) belt moving at a fast speed.
I’d look into increasing your motor size to at least 2hp and going well over 4000 sfpm. Then buy 36 grit norton blaze or cubitron 2 belts. They’re more expensive, but eat steel fast.
It also grinds faster to grind with a wheel on your 2x72.
 
Lower grit belts for a start. Otherwise an angle grinder with a low grit flap disc should hog pretty good. You will have to be careful to not end up with hellacious dips and valleys. Can flatten again on your platen after.
 
Material removal rates are dictated by 3 things: horsepower, contact pressure per square inch, and depth of cut per tooth.

Lower grit increases depth of cut.
Lower contact area increases the pressure per square inch.
Horsepower allows a given depth of cut to occur at a given pressure for a given contact area.

Angle grinders seem to move metal fast because they reduce the contact area to something sustainable for their low HP motors. If you want to move metal quickly and in a fashion suitable for knifemaking, IE relatively evenly, then a 2+ hp 2x72 with a 36 grit belt is likely going to be the fastest.

In my shop the fastest way for me to reduce stock thickness (other than milling) is on my 2.5hp surface grinder with a hard wheel and 36 grit belt at 6000sfm. The wheel reduces the contact area (relative to a platen). The hard backing of the magnet increases pressure over that contact area. All I have to do is vary the feed rate to the point that the motor can sustain without slowing. I don't think anything of taking 1/4" material down to 1/8" if I need to with that machine. I can do it in 4 passes.
 
Thanks a ton for all the tips, guys.
I figured that 36 blaze belts would be a common solution as I've used them before on my 1x30 harbor freight when I was getting started and they worked fast and long. My biggest issue is that i dont work professionaly so money saving is one of my top priorities. I don't really have any problems buying those belts, though, because I know they're the real deal.
 
I will put in that a serrated wheel will remove metal a lot faster than a smooth wheel.
 
Yep, a 6” or 8” wheel, for small contact area and lower grit belts.

Plus forging closer to size, if you do that.
 
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My primary setup for steel removal involves three grinders (1 pcs 3x78 and 2 pcs 2x78), each with a 3 HP motor. One is used with a surface grinder attachment together with a 8" serrated contact wheel. I run it with 3x78 belts, and with a 36 or 60 grit belt you can accurately remove a lot of material very quickly. Unfortunately my contact wheel is a little soft, so I will be ordering a harder one.

The next grinder is the heaviest which I use for profiling and bevel grinding. For profiling I begin with a 8" contact wheel with a 36 grit belt at full speed (around 6000 SPFM), I leave about a millimeter for the flat platen and a 60 grit belt to get the profile done. Actually, I don't profile my blades on the bandsaw anymore since the grinder gets the work done so damn quickly.

The third grinder is mostly used for small wheels in vertical mode.
 
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Best would be a rotary surface grinder, you can buy a decent one for around $50,000. That probably won’t help here, though.

Hoss
 
Charles N said:
I've been forging for about 2 and a half years and my biggest enemy has always been getting that last ounce or two of steel off my blade. I was wondering what y'alls best method for heavy stock removal and shaping is, particularly for reducing the thickness. My arsenal includes:

2x72 belt grinder (homemade, 1 HP but it works) My lowest grit is an 80 grit alum. ox.
8in bench wheel grinder (not a beast , will occasionally bog down if i press hard enough)
Files (and a scraper, too)
4.5in angle grinder

I'm also considering buying a 7in angle grinder
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80 is approaching a finishing grit. Buy those blaze 36 grit or I find VSM Ceramics to work great. I’m a stock removal maker and grind my FFG blades after HT. After about 60 percent of the grit is used on a belt. I move the belt to the profiling etc pile. Give this a try with your current 1hp motor & 36 and the 60 grit etc belts. It will work. Especially with non hardened, Carbon Steels ,
 
You can get the VSM from pops for around $5 .I use my 2hp on 110v so its around 1.5hp and it is much faster than a angle grinder and it took a fair bit of practice to be able to slow it and still have control of the grind. kuraki kuraki gave a great description of how it all works. Just use those concepts to guide your belt selection.
 
I like an 8 or 10 inch wheel for stock removal like others. Also a cup wheel for your angle grinder to remove scale and stock after forging they last a long time.
Gilbert McCann
 
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