How To Surface Grinders Question

[David Schott]

Hi,
As I go straight down the rabbit hole in getting more perfect folders I'm working on the small nuances like perfect shield inlays. A big factor is DEAD flat blade/spring/liner interface for a truely gapless fitup.

My current setup is my KMG and a granite plate. This is not ideal because:

• I can easily get surfaces dead flat individually. This does NOT guarantee, however, that those flats are square to my holes OR perfectly parallel to one another front to back and top to bottom. As such I end up having barely perceptual spine gaps. If my spring runs out another .0005 off parallel on two planes I get a visible gap (visible meaning the spine doesnt legit look like a single piece of steel, not just with tiny lines hairpin lines)

It feels to be the only really repeatable solution here is a surface grinder where I could dead flat the blade and spring at once during a few critical steps in the operation.

Questions:

• Lots of semi-full size machines available aftermarket in the $1000 range. Logistics moving them a solvable problem but I know VERY little about condition, exactly what to inspect, etc.
• How do these hold up? Would an older machine hold the tolerances I'd need which would be .001 or so over the length of a blade/spring?
• Do I really need a huge fullsize surface grinder here? We're talking flattening blades (the tang really) no more than 4" in length and springs about the same and no width.
• Do they make "benchtop" surface grinders that hold this kind of accuracy? I could care length how long this would take do to how infrequent I do this and the fact that doing it by hand on a surface plate SUCKS. I have a fullzie bridgeport mill but the idea of clamping, fixtures and such to even out blades, also leveling the non-pretty surface my 1944 mill leaves behind to clean up.

What are you guys using? My pricerange is right around $1000 but I could creep to $1500 if needed.

Thanks
-Dave

 

[HSC ///]

Boyar Schultz. About $700 in Los Angeles. Not super clean or fancy but works just fine for .0005

$250 magnetic chuck
$100-200 in various wheels depending on steel and desired results

with a sine plate works great for tapering tangs on full tang fixed blades

doesn’t take up a lot of room
I use a vfd to power it
It comes apart at the top of the base and is easy to move with an engine hoist

look for easy free movement in all axes.

if I was inspired I would take it apart and clean it....

 

[David Schott]

Boyar Schultz. About $700 in Los Angeles. Not super clean or fancy but works just fine for .0005

$250 magnetic chuck
$100-200 in various wheels depending on steel and desired results

with a sine plate works great for tapering tangs on full tang fixed blades

doesn’t take up a lot of room
I use a vfd to power it
It comes apart at the top of the base and is easy to move with an engine hoist

look for easy free movement in all axes.

if I was inspired I would take it apart and clean it....

612 model? I see similar around me 1000-1500 with chuck and wheels. Lots of surplus old industrial in this area with bridgeport close by too

 

[HSC ///]

612 model? I see similar around me 1000-1500 with chuck and wheels. Lots of surplus old industrial in this area with bridgeport close by too

yes, 612

 

[Signalprick]

What about a surface grinder attachment for your KMG? Most I've seen vary in price from $800 - $1100. I'm building a very simple one for my Ameribrade for less than $200. I borrowed the design from a couple other makers who are getting to .0005 flat with it.

 

[bmilleker]

What about a surface grinder attachment for your KMG? Most I've seen vary in price from $800 - $1100. I'm building a very simple one for my Ameribrade for less than $200. I borrowed the design from a couple other makers who are getting to .0005 flat with it.

In my experience, a home built solution works well, aside from the edges. A soft contact wheel, even 90 duro, will round the edges when it first makes contact with whatever you are surface grinding. I would love a steel contact wheel for mine. You won't get as pretty of a finish, but it should be totally flat.

 

[REK Knives]

Yeah if you want dead flat you need a legit stone surface grinder. And you will have to spend a lot of time figuring out warping issues - comes with the territory of thin pieces.