Home Built Surface Grinder

Ken H> said:
Larry, Does Travis not have that mounted on a 1-1/2" already? OR - does he use a different size tool bar? Would you care to comment on the accuracy of the surface grinder attachment? Will it hold a finished blade to .001" over a 10" blade? less?

Now to get metal on order for rest of project - Does anyone see a problem with building magnetic chuck from aluminum? I think the rest is aluminum.

Ken H
Click to expand...

Here is a good read. https://www.mmsonline.com/articles/is-magnetic-workholding-for-you
 
KnuckleDownKnives said:
Here is a good read. https://www.mmsonline.com/articles/is-magnetic-workholding-for-you
Click to expand...
If I understand this article correctly, a steel chuck would hold your work "stronger" than an aluminum chuck, given a constant number and strength of permanent magnets used in said chuck? But that may be a moot point if One Armed is getting sufficient holding power, especially for those of us who don't have a mill and are trying to use an old drill press to gingerly "mill" out the chuck.
 
AlaskanHunter said:
If I understand this article correctly, a steel chuck would hold your work "stronger" than an aluminum chuck, given a constant number and strength of permanent magnets used in said chuck? But that may be a moot point if One Armed is getting sufficient holding power, especially for those of us who don't have a mill and are trying to use an old drill press to gingerly "mill" out the chuck.
Click to expand...

If you feel it is sufficient for you, go the route you choose., I posted it because not everyone will choose to go that route. By the time I buy the tooling to do it in my junkie drill press I could pay someone with the proper machines to machine it for me. Ken asked about the magnetic holding power of aluminum. I pointed to an article where he could get some decent info. Me personally, I'd rather have more holding power. I think it's safer to have more than "just enough". Might accidentally crank it in a bit too far and take off more material than desired. Stronger magnet stronger hold. Might get distracted crank it in and feed the part from the wrong side. Stronger magnet may save a limb, or life... I haven't seen any "real" magnetic chucks made from aluminum. That's just me...
 
Last edited:
KnuckleDown is right on this guys. There is no "one size fits all" for this. I'm like him....more is "better-er" approach! I chose aluminum because I knew I could mill it with my tiny HF drill press. I started with 10 magnets because, well, this was the first time I did it! And I didn't know how many I would need. But after, I wanted MORE holding power. I only had room for 1 more magnet because of the spacing. With 11 magnets, I have exceptional holding power now. There is NO worries of a blade coming off. And my magnets are below the surface quite a bit! As I face the surface, the part will come closer to the magnets. Which will increase the holding power even more. But, if I were to do it again with aluminum, I would use 16 magnets. This leaves slightly less than 3/8" spaces, and will provide hundreds of pounds of holding force! A steel flat would be even more! If you are having the piece machined, use steel. If doing yourself, go with aluminum.

Also, for those doing themselves... you will need to pick up an Axis table. This is the one I got. And it has worked decently for how cheap it is.

https://www.amazon.com/gp/aw/d/B01K...13&pi=AC_SX236_SY340_QL65&keywords=axis+table
 
KnuckleDownKnives said:
If you feel it is sufficient for you, go the route you choose., I posted it because not everyone will choose to go that route. By the time I buy the tooling to do it in my junkie drill press I could pay someone with the proper machines to machine it for me. Ken asked about the magnetic holding power of aluminum. I pointed to an article where he could get some decent info. Me personally, I'd rather have more holding power. I think it's safer to have more than "just enough". Might accidentally crank it in a bit too far and take off more material than desired. Stronger magnet stronger hold. Might get distracted crank it in and fee the part from the wrong side. Stronger magnet may save a limb, or life... I haven't seen any "real" magnetic chucks made from aluminum. That's just me...
Click to expand...
Understood. I've got a Shop Fox drill press, "variable speed" via pullys. Do you think that I could get away with very slowly "milling" steel with it? Or is that a really bad idea? I understand that a drill press isn't a mill, so tolerances of the finished product will be a bit sloppy compared to having it done by a real machinist and mill, and there is a chance of destroying the bearings in it, but do you think it could be done? I have no clue how quickly the thrust bearings in a drill press would be damaged by a side load.
 
Don Hanson III said:
This 'surface grinder attachment' is not as accurate as a 'real' surface grinder and will not replace mine. I have done some measuring and find .001" difference from end to end on a 8-10" bar and a 1/2 thou difference side to side, but not every time. It depends a lot on the belt and rate of feed. Plenty flat for fixed blades.

It is extremely quick for cleaning up a forged blade, or billet though, I mean Very Quick! & tapering a tang is Unreal!!!

I'll still use the old grinder with stone wheel for folders, but the Wuertz SG will see a lot of use in the shop here!
Click to expand...
Messed with the Wuertz SG a little more since posting the above and found more accuracy. After lightly surfacing the chuck again, with a Good 180 grit belt and tracking side to side for even belt ware. This is the key.

I could make folders with this thing and do know a guy who's made over a hundred with one.

But I'm more excited with the fast stock reduction, as almost every piece of steel I use is forged. Blades, bolsters, guards, springs, spines, frame handles, etc, etc.
 
AlaskanHunter said:
Understood. I've got a Shop Fox drill press, "variable speed" via pullys. Do you think that I could get away with very slowly "milling" steel with it? Or is that a really bad idea? I understand that a drill press isn't a mill, so tolerances of the finished product will be a bit sloppy compared to having it done by a real machinist and mill, and there is a chance of destroying the bearings in it, but do you think it could be done? I have no clue how quickly the thrust bearings in a drill press would be damaged by a side load.
Click to expand...

I know nothing about that press, I wouldn't try it. Probably be breaking bits very easy.
 
AlaskanHunter said:
Understood. I've got a Shop Fox drill press, "variable speed" via pullys. Do you think that I could get away with very slowly "milling" steel with it? Or is that a really bad idea? I understand that a drill press isn't a mill, so tolerances of the finished product will be a bit sloppy compared to having it done by a real machinist and mill, and there is a chance of destroying the bearings in it, but do you think it could be done? I have no clue how quickly the thrust bearings in a drill press would be damaged by a side load.
Click to expand...


Well, the bearings in my drill press are ok. No harm done! I have milled a little mild steel so far. You will need carbide end mills. And no larger than 1/4". 3/16" even better. But it will take a LONG TIME! And this is coming from someone who has a plethora of time on his hands!

Oh, I did a quick accuracy measurement. On my crappy digital caliper, it was right about .001"-maybe slightly more. I haven't surfaced my chuck either yet. But I dropped my caliper and it cracked! Need a new one now to check anymore. But I say, for sure, "It's good enough for government work!" LOL. AGAIN, I agree with Don. I am elated over the accuracy/speed it delivers! Still blown away I built this thing.

I'm like a little kid smiling with glee, over the first maccaroni necklace I just made for my mom! All proud of my hard work & stuff!! LOL.
 
what is it about this style of attachment that introduces error ? does the support arm flex, or is there play in the sliding track and wheels/bearings, or something else ?
 
Ken H> said:
Larry, Does Travis not have that mounted on a 1-1/2" already? OR - does he use a different size tool bar? Would you care to comment on the accuracy of the surface grinder attachment? Will it hold a finished blade to .001" over a 10" blade? less?

Now to get metal on order for rest of project - Does anyone see a problem with building magnetic chuck from aluminum? I think the rest is aluminum.

Ken H
Click to expand...
He makes an adaptor to fit a KMG that is used vertically and he tool bar is 1/ 1/2 inches except for where it connects to his grinding wheel where his bracket holds it to the rest of the attachment. I made my own tool bar from 1 1/2 aluminum stock to fit horizontally and had a 1/4 inch milled off two sides about 8 inches back. You can just barely see the cuts in my photo. I have measured the end to end and top to bottom of my ground blades and they are very close to .001. My guards fit so tight you would have a hard time getting a single edge razor to stick between them. For all practical purposes this is all I need although a traditional surface grinder properly used might have more precision. I have never used a traditional surface grinder so I cannot say. Larry
y4vrPBil.jpg
 
The only surface grinders I've used are stone, and those - you can hold .0001" with no problem.... by taking care. It's been more years than I like to think since I used them, but they sure work good. Got to dress stones, and have the right stone.
 
I was contemplating building a free standing stone surface grinder. Would have been close in cost. But this one was too appealing. Given the speed, space & weight savings, and accuracy within what I need, it was hands down a better option for me. Not for everyone.

BTW, I messed around some more, and tried milling some mild steel.

Here is my trusty-dusty, CRAPTACULAR mill set up.
BNaYMHP.jpg


This is a piece of mild steel. It is 1-1/4" wide. And that is one of the magnets I used. Oh! As a side note, they are very fragile, and will shatter when dropped! Even a short distance, LOL!
IXbHzhO.jpg


Just this 1-1/4" slot took me about a half hour. I used a 5/16" CARBIDE end mill, at the slowest speed my drill press goes, which is 760rpm. Slower would be better. If you choose to make the chuck from steel, on your own, just go very slow. But, YES! It can be done with a cheap, underpowered drill press.
wSZt58P.jpg
 
While were on the topic of surface grinders and non recommended drill press use, I could swear I saw someone build a tiny Blanchard grinder out of a drill press a while back. Unfortunately I can't remember where it was, and don't know how well (or if) it worked
 
"Non recommended" LOL! I like that. It's SOOO TRUE! HAHAHAHAHA! We do what we must sometimes. "When life hands you lemons", ya know? But speaking of that... I desperately want a mini mill. And I am slowly saving up for one. (VERY slowly!!) But eventually I will get one. Wait for one of the times they put out the 25% off coupon, and I can pick up the Harbor Freight Mini Mill for just over $500. I should have grabbed it long ago...but hind sight and all. Oh well, hopefully in the Spring. And then maybe I'll do another magnetic chuck, from steel.

Or* Maybe I'll just go ahead and do another one.... In steel.... NOW! Just because I know I can!:D
 
john april said:
what is it about this style of attachment that introduces error ? does the support arm flex, or is there play in the sliding track and wheels/bearings, or something else ?
Click to expand...
Nothing flexes, but it's just not heavy and solid like a real SG. Biggest thing is what Geoff said, belts & in this situation not being able to slowly track the chuck across the full width of the belt surface.
 
Don Hanson III said:
Nothing flexes, but it's just not heavy and solid like a real SG. Biggest thing is what Geoff said, belts & in this situation not being able to slowly track the chuck across the full width of the belt surface.
Click to expand...

Both of what you said are what I want to add to mine when I build. More beef, and cross tracking. I'm tempted to build an electro magnetic chuck as well utilizing a couple transformers from junk microwaves.
 
My new to me Bridgeport arrives this Friday, I've been waiting for it to build a magnetic chuck. I am building a surface grinder attachment for myself, but I was thinking about building the magnetic chucks and selling them because they are hard to find and very expensive. Possibly even just machine slots in the blocks and let people source the magnets themselves.
 
You must log in or register to reply here.
Back
Top