Any one of you fuckers ever delve into building a homemade belt

>>1230025
Why do the 72'' ones work better for knives than the 30"? This is a real question

>>1230025
I salvaged an old table saw motor in planning on using for one. Local steel distributor is 40 min away though, so I've been waiting for a reason to make a run up there.

I found a variac in a junk shop that works.


As far as the design goes, take a look on YouTube. Loads of guys building them. You can either buy the wheels for ~100USD or turn them yourself in a grinder or drill press. Prob worth the money to just buy them

>>1230026
longer belt = longer life.

despite being twice as long, they actually last a lot more than double the lifespan.

72" / 186cm blets also have the advantage of being able to run larger contact wheel ranges - ie, 50mm radius wheels for fullers/scallops, and 250mm / 10" wheels for hollowgrinds.

they also allow a decent width between idler wheels, which lets you put a decent width/length platen in. more length there reduces the heat buildup from friction, which causes wear and premature belt failure. it also allows you to grind flat faces easier.

lastly, 2x72 is one of the widest range of belts, including cubitron II and Trizact.

There are many videos on youtube that show ways to build a belt grinder. You can machine your own parts or just use 2x4 and some skateboard wheels. I would recommend typing in "how to make a belt grinder" in youtube and watch a couple of videos and come up with a design. Another reason that the 2x72 belt grinder is better than a 1x32 belt grinder is that the length of the belt slows the heating up of the material you are using allowing you not to mess up the temper or burn your hands. hope this helps

I'm building one right now, mostly based on https://dcknives.blogspot.nl/p/2-x-72-belt-grinder.html
I've 3D printed the wheels from PETG, I don't know how well they're gonna work, but they only show about 0.2mm inaccuracy and they cost like $8 in materials so worst case I'll buy better ones later on.
Motor is probably on the weak side at about 300W, only thing I had laying around.

>>1230025
Some of the better designs I've seen involve using a treadmill that gets pulled to bits, attach rollers, drive wheel and various ways/shapes of tensioning the belt. Stuff like a platen can be make or bought.
Advantage of the treadmill as a drive unit is the variable speeds built in and there's literally dozens of the things for cheap or free that get bought by people who hate them.

>>1230176
Dead treadmills usually have a control board failure while the motor survives. Lots of interesting parts including the steel frames can be repurposed.

>>1230787
Should be plenty of live ones out there, they seem to be bought by a lot of people who just end up tossing them in the back of the garage.
About the only thing is they 'could' be a little underpowered with some types, so a flywheel or step-down pulleys to give it a bit more torque could be a factor in your design. For most people though they're generally happy enough with a 1.5-2hp motor and 1 speed, which you can make a knife on just fine.

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Here is mine . can't write details ATM if the thread is still here in 3days I'll explain what I used

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>>1231451
>if the thread is still here in 3days

fuck that. that's some cool shit. start your own thread if need be. I want to make a 72" but I'd rather buy a motor than look for a treadmill.

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>>1231451

pic saved to troll /pol/

>>1231451
That's pretty much the same design as the one I'm making >>1230146
Gonna be a few more days until I get the parts I'm missing, then I'll take some pictures too.

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>>1231451

you used the centered holes at one end and the offset holes at the other.

fine tuning the plumb or what. i love your work.

Finna?

>>1230025
>Jobless gunsmith
So you're a dumbfuck who spams ancient /b/ "infographics" in /k/ inbetween parroting molon labe pamphlet shit in "CAD" threads?

>>1230146
>Motor is probably on the weak side at about 300W

your motor is less on the weak side, as positively anaemic.

I run my 2x72 on a 2.5kw motor through an invertek digital inverter, and I've managed to bog it down during platen grinding. 300W is going to have so little power that the only sort of grinding you'll ever do is short little touches which will glaze the belts.

you need at least 6x that motor's power for a passable grinder.

>>1231457
how would that troll /pol/

>>1231482
>tfw I made a pedal powered one 20 years ago and it worked fine for knife work

>>1231451
I think I remember seeing that one before a long time ago?

Don't use a treadmill motor if you're going to use this on a regular basis. Use a TEFC (totally enclosed fan cooled) motor because getting steel dust in your giant spinning magnet will fuck it up in short order.

Get at least 1hp. The full time custom makers use 2-3 hp motors.

2x72 is the best. 1x30 works if you're poor or just starting out and not sure if you're going to stick with it, but a 2x72 is twice as long and twice as wide. I have tried and failed to make kitchen knives on a 1x30, it just won't reasonably do it.

Heat treat is #1. If you can't afford an oven stick with simple carbon steels like 1075 and 1080. These were designed for "get it hot then dunk it" primitive HTs. Stay away from 1095, it's abundant and affordable but requires a soak in an oven. The name is close but the level of skill and care required is not.

No stainless that I know of is beginner friendly unless you send it out to be done professionally. It would be worth it if you sent a batch that you planned on selling, but not for one-at-a-time practice knives.

O1 and 15n20 CAN be simply heat treated. They need a soak to reach their full potential (and should if selling), but a backyard HT is good enough for personal use. 15n20 you can get cheap in the form of pieces of giant bandsaw blades. O1 can be hardened and annealed again and again (in case you do it wrong) with relatively few negative effects compared to other steels but costs more because it's typically precision ground.

Lawnmower blades, leaf springs and other mystery steels will make knife-shaped objects but you need to know what steel it is to be able to harden it properly, if you even can. Sawblades typically only have good steel in the teeth, the body is mild still that won't harden properly.

Tempering temperatures and times vary. If you use a kitchen or toaster oven, get a baking thermometer to place next to it, don't rely on the oven itself. Mine varies +- 25 degrees each time you turn it on.

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>>1231474
Don't be a bitch to strangers on the internet anon.