Surface grinder

Don Hanson III said:
I generally do .005" down & .020"-.030" over. Then for the finial finish go down to a .010"-.015" step over for a finer finish.
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Whatever you do - I recommend a 1" wheel.
Gator belts are your friend. They seem to taper the backing/grit thickness at the splice, which results in a super nice finish.
I normally remove .003" depth and I can step over .100" - .200" per pass when stock removing.
I stock remove at 60 grit.
When I finish with the A100 - 65 - 45 - 30, I only remove about .0005" - .001".
You need to take your material almost to a complete finished dimension before switching to the Gators, as no matter how well you've done, even the hardest rubber wheel will compress when removing too much material.
But when you switch to the Gator A30, the finish is extraordinary.
A 1" wheel is the way to go.
Did I already say that?
Oh, yeah, and don't forget - use a 1" wheel.
 
javand said:
I have a large K&T vert, and always intend to rig up a system for roughing billets but never get around to it. The big trick is work holding, without having to sacrifice any significant portion of the billet end, or have a second op milling the hold down area when you flip.

A mag table for the mill would be nice, but you can't get away with a standard surface grinder permanent mag chuck bolted to the mill, and hog at the rate a big mill can handle safely.

It's definitely something I intend to play with if work ever allows.

Although I've always thought a large horizontal would be the best for this. It's the type of op they were built for.


The thing is though, I'm not certain either will be more efficient from a standpoint of how much of my "attentive time" it'll take. The advantage of a large surface grinder with a contact wheel in this case is that I can feed the Z until the machine starts bogging slightly from load, with the auto feed on, walk away, and come back 20 mins later, and either do a quick clean up, or repeat.

The time it takes grinding isn't relevant, just the time I spend actively manning the machine.


That wont be the case with a mill, so unless I can do it in one or two passes, and get a finish good enough that I don't have to grind it further, it won't have any real advantage.

On the other hand, I do think that it's achievable, with the right setup, mill, and tooling, although, that's mostly a leap of faith.
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The idea I had come to mind would be setting up 3 6" anglocks side by side, to usefully support up to about a 24" billet without any extra clamping or setup. Of course that's about $3000 worth of vises...
On just smoothing out and descaling a Blanchard or your setup with a large surface grinder would probably be faster.
I can see the mill setup working quite well for ladder pattern and the like though with large amounts of metal to remove.
 
knife to a gunfight said:
Most guys use a single point diamond dresser to dress their wheels. You can buy holders for them that you put on your mag chuck (I think most guys just make them by drilling into a piece of bar stock and putting in a set screw), and these will hold your point at the requisite angle, and then you can just traverse the point across the face of the wheel.
The basic jig is very simple, though you can also get into more complex fixtures that profile/contour the wheel for more advanced operations.

Dressing has it's own idiosyncrasies to be sure, and there's a couple of different techniques on getting a proper dress depending on wheel type, desired finish, etc... Obviously you want your wheel to be balanced before you dress, and above all, you want to make sure your machine is warmed up, or you may as well not dress the wheel at all. Position and angle of the dresser certainly play a role as well, but the main thing is that you don't want the wheel pushing INTO the dresser, but going away from it, for obvious reasons.

Then there's coarse dressing vs fine dressing, etc.... which all plays a different role in finishing based on stone and material type.

Now, I'm by no means an expert at surface grinding, but I can tell you this: If you're looking for perfect finishes and tolerances within .0002" or better, there's a LOT more too it than just throwing any old stone on and hitting the go button. :D I spent hours on my machine making all kinds of changes and adjustments trying to chase this finish or that finish with stones AND belts, and there's a lot of little things that make big differences in results, and if you have one little thing wrong, you'll be chasing your tail until there's no wheel left. ;)

Fortunately, I find it fun to tune and tweak things and learn what affects what and which setup is the best for what I'm looking for. Other user's mileages may vary.
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Oh man I've got a lot to learn. I mean this is just one small piece of the knife making process and I don't even understand this. Little lone know much about making a knife. I sure do appreciate everyone's willingness to give advice tips and knowledge! Thanks all who have contributed thus far.
 
Don Hanson III said:
I grind hard & soft steels. No difference I can see.
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In the thicknesses we're working with it doesn't make much difference.

On large parts hogging with a stone, it does. You can take a much more aggressive roughing cut on non-hardened steel with the right stones, where accuracy is less important to speed, but on thin parts where you don't have a lot of room or time to rough and then re-setup, you're pretty limited on the depth of cut you can take before the part starts warping off your chuck, and hardened steel is more sensitive to this, plus you'll destroy the temper and induce major stress if you get too aggressive.
 
The biggest thing for me with soft steel is that it tends to load the wheel faster. I'm sure that's rarely an issue grinding a couple knives at a time, and the wheel gets dressed between jobs and never has a chance to load up.
 
javand said:
In the thicknesses we're working with it doesn't make much difference.

On large parts hogging with a stone, it does. You can take a much more aggressive roughing cut on non-hardened steel with the right stones, where accuracy is less important to speed, but on thin parts where you don't have a lot of room or time to rough and then re-setup, you're pretty limited on the depth of cut you can take before the part starts warping off your chuck, and hardened steel is more sensitive to this, plus you'll destroy the temper and induce major stress if you get too aggressive.
Click to expand...

Thats an issue I've noticed is warping and even temper damage (lines where the wheel traversed on the flats, on a Damascus blade - really noticeable after etching). So to prevent warping what dough suggest, flood coolant with .002-.003" depth of cuts max?
 
razor-edge-knives said:
Thats an issue I've noticed is warping and even temper damage (lines where the wheel traversed on the flats, on a Damascus blade - really noticeable after etching). So to prevent warping what dough suggest, flood coolant with .002-.003" depth of cuts max?
Click to expand...
I've never had that problem using the stone I posted above, taking .005" down and using No coolant, dry grinding. The wheel is key.
 
I've found the warping and burning usually happens when I either stepover too much, or don't dress the wheel frequently enough.

I'm going to try and find the wheel Don uses though. Norton isn't easy for me to get, my supplier sells CGW and Carborundum. I'll see what the equivalent of it would be, or just find the Norton elsewhere
 
Don Hanson III said:
I've never had that problem using the stone I posted above, taking .005" down and using No coolant, dry grinding. The wheel is key.
Click to expand...

Wow that's awesome Don! So if you check it on a granite plate it's dead flat after?!
 
Karl B. Andersen said:
Whatever you do - I recommend a 1" wheel.
Gator belts are your friend. They seem to taper the backing/grit thickness at the splice, which results in a super nice finish.
I normally remove .003" depth and I can step over .100" - .200" per pass when stock removing.
I stock remove at 60 grit.
When I finish with the A100 - 65 - 45 - 30, I only remove about .0005" - .001".
You need to take your material almost to a complete finished dimension before switching to the Gators, as no matter how well you've done, even the hardest rubber wheel will compress when removing too much material.
But when you switch to the Gator A30, the finish is extraordinary.
A 1" wheel is the way to go.
Did I already say that?
Oh, yeah, and don't forget - use a 1" wheel.
Click to expand...


Has anyone tried a solid aluminum wheel for that ?
 
Don Hanson III said:
Geoff, I get that stone from MSC.
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Unfortunately MSC won't ship up here. I generally deal with KBC for everything machine shop. They sell lots of Norton products, but just not Norton wheels. I'll check Travers and ACT, I'm sure someone up here will sell them.
The carborundum wheels are quite good though, so I might try to find what their equivalent product would be
 
Well it seems the wheel I've been using is the carborundum equivalent of the one Don recommended. That would probably explain why it seemed to work quite well
 
That sounds exactly like what I'm running.
My stone is a pinkish color but otherwise seems about identical.
I've got a couple finer stones I'm going to play around with for finishing flats, but j. I'm definitely happy with these for roughing stones.
 
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