unsurprisingly, grinding stones make tasks easier

[solarbird]

I popped down to the hardware store last weekend to get a grinding wheel that I could use with my drill press to re-tool the end of one of my chisels, after I damaged it by discovering a screw inside lumber the hard way.

Put a real chonk into the end of the chisel. I was mad, particularly given that several months ago I spent a few days repairing/restoring all three chisels from the rather sorry (and dull) state I'd let them get into, and I wasn't looking forward to several hours grinding this damaged one down by hand again.

Unsurprisingly, it's all a lot easier with power tools. xD It took less than an hour and only took that long really because I've never done it before. I was worried about having a stone spinning parallel to the ground rather than perpendicular, but it didn't come off so I guess it's safe? Having it on the slowest speed probably didn't hurt stability either.

It's not excitement, but it is "achievement unlocked!" so I'm posting about it. xD

In 3D printing news, I've been mostly doing a lot of repeat prints of difficult objects with different filaments to figure out how to make all those various difficulties work and generally get them figured out. It's a lot of repetitions and I'm kind of burning through a good amount of filament, but it's for science - or at least engineering - and I am writing it all down, so there's that.


I even got blue silk fan shrouds working
Right now I'm working on a backplate mounting for the fan system shown in the above photo. I've got a mount now, obviously, but if I make it just a tiny bit wider it holds more tightly and I want that. I'm trying to do it with white HTPLA, which has higher temperature tolerance than what's attached now, but it's giving me real fits and coming out between ugly and dysfunctional. FilaCure says this isn't beginner PLA, and while I've used it successfully before, I have also noted when doing so that they are entirely correct about that. It's hard to work with. Good, once you get it nailed down, but difficult.

I have a lab notebook again, lol. Been a while.

Comments

[stickmaker]

Do you need to reharden the cutting edge of the chisel or is the steel hardened all the way through?

Also, using a slow grinding speed helps avoid overheating the metal and detempering it. You still might need to keep a small container of water handy to dip the blade in periodically, if the grinder isn't already water cooled (like an old-fashioned grinding wheel).

[solarbird]

There's a pretty clearly hardened area at the end, that I'm more than halfway through at this point, I think. They aren't very good chisels and were rather cheap, but I use them pretty rarely so they've been fine this long. When I do finally need to replace them, I might step up a level - they've never really held edges that well.

Oh, it's not a grinder, it's a drill press! I'm just using it as a wrong-angle grinder. I was also grinding against the side of the stone, I don't know if that's considered bad or what. I never got the metal really very hot - it only got at most warm to the touch - but I did water it occasionally anyway.

[vatine]

I suspect (depending on the exact material make-up of your grinding wheel) that it would vary between "fine" and "perfectly fine" having it spin co-planar to the ground. Might make it harder to keep the wheel wet, but that's mostly only for large sandstone-type wheels anyway.

I'd probably, personally, gone for a power file for the coarse re-shaping, but that's because I already have one (think itty-bitty hand-held belt grinder with very narrow belts). I should go see if I can find some finer-grit belts, at some point, I have 40-grit and 80-grit and that's really quite good for rapid removal, but not so fine for a finer polish...

[solarbird]

I used honing oil. Is that bad? It's what I use when sharpening other knives on the stone I have for that - which is how I also put down the actual edge on this thing, the grinding wheel was way too coarse for that nonsense.

(Well, okay, I use honing oil on the first-level stone. If I'm going the next two levels up, I use water because that's on a Japanese water stone, not an oil stone. With these chisels, I really only bother with the oil stone.)

[vatine]

Nah, oil is perfectly fine. May not be 100% needed (those large slow sandstone wheels 100% need to be wet to work properly), but definitely won't hurt. Just try to never use water on a wheel taht you've used oil with. Nothing super-bad will happen, but there's going to be not-as-good-as-normal results for a while.

[solarbird]

So I should have an "oilstone wheel" and a "waterstone wheel" basically, like I do with sharpening stones.

Okay, that strikes me as reasonable.

So do grinders have a water reservoir somewhere to keep wheels wet? Or have I just never seen anyone wet one because they edit that out of the video?

[vatine]

Most small grinders don't. Larger sandstone grinding wheels (think "your old-timey sharpening stone") tend to have a water reservoir at the bottom of the wheel.

I have seen quite a few machinists on YouTube having misters or similar to keep a continuous (if not high-volume) wetting of the work piece, more to get heat off than to add liquid for the usage of the wheel.

Modern abrasives don't rely on being in a slurry to do their work, so I suspect you may actually get away with running the wheel dry, as long as you have a nearby reservoir of water to occasionally dip the work piece in. When I've been making blades, I was using a 2l PET bottle with the top cut off as a handy nearby "dunk it in, once warm" (but, of course, at that point, the metal is neither hardened nor tempered).

You mentioned earlier that you never took it past "warm to the touch", that's good, once you're past about 150°C - 180°C, you're into tempering ranges. Still probably tempering ranges that are below what the original temper was, so (probably!) no actual change.

[solarbird]

Also also, that's a new tool on me. WEN (who also made my drill press) offers a little one for $40 (without belts, $60 with) and it's a new one on me in general! All my files are just, you know, files. xD

[vatine]

I bought mine so as to stop using an abrasive drum on a dremel-alike for making knives. It does make it a lot easier to get the bevels more consistent, when I use teh power file strapped to something, so I have two hands free to control the metal piece. With material in one hand, and the power file in the other, it is only slightly better, I think mostly because as you move the belt left/right over teh material, the belt is moving in an orthogonal direction. With a dremel-alike, you will be doing "conventional grinding" one way and "climb grinding" the other.