A few questions on shop tools, never made a knife before...

Josh Dabney said:
Lets talk a little about going from the quench to the temper-

How fast do you need to temper ? At least long enough for the blade to cool to room temp first. (Probably 10-15 minutes minimum) In certain circumstances with certain steels and certain quench mediums then there is the risk of the blade cracking between the quench and temper. ESPECIALLY when using water or brine as a quenchant and to a lesser degree fast oil like parks 50.

O1 or A2 you shouldn't need to worry about and there's never a need to rush.

The purpose of the low temp kitchen oven temper is just a stress relief not to reach your target hardness. The kitchen ovens readout is a setting only and not the actual temp. inside, Heating a large volume of air like that is prone to large temp. swings also. Checking our kitchen oven with an oven thermometer revealed it's much hotter than the setting.

There's more to it than that but it's at least a summary to help you understand.

Metallurgy is a DEEP subject and there's ALOT to learn

Having Doug Lester in the conversation is is a bonus for you ! He's very knowledgable about metallurgy and could offer a far clearer explanation than me.

-Josh
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Hmm...

So tempering can't be done in a conventional oven? I might be in trouble then!
 
Josh, you just scared the heck out of me. There are real metallurgists that hang out on these boards and I'm not one of them. I'm just willing to hit the books and the diagrams and try to figure things out. There are still several concepts that I battle with. As Kevein Cashen-one of the real metallurgists-pointed out, a lot of the texts don't mention the exact conditions behind their statements or identify when there are other things that are going on besides what is being discussed. It takes a while to put things together. Of course it would be easier if I could affort several thousand dollars worth of testing equiptment so I could test some of the assumptions that are made during heat treatment. I'm still dealing with trying to find a used hardness tester that can test knife blades and is cheap enough to afford.

Doug
 
I appologize for being misleading here.

Tempering can done in the kitchen oven with fine and repeatable results as long as your aware of you need to check the temp with an actual thermometer. I did it this way for a long time.

Get one of these to hang on the rack inside the oven-
http://www.walmart.com/ip/Mainstays-Oven-Thermometer-00620W2/14913167

I think they're about $4.99 at walmart

I PREFER to use the Evenheat for tempering due to accuracy and repeatability of the temp. but fine results can be had with a conventional oven as well.

Let the blade cool to room temp after the quench then at least give it a good cleaning with hot water and dishsoap to get any oil residue off the blade. I like to clean one side up on the grinder to nice shiny steel so I can see the color I've got after tempering. If your plate quenching A2 in foil this will only require a light going over with sandpaper by hand to get clean steel.

I don't do this because color is necessarily an accurate indication of hardness but just to check for a red flag like a purple blade. And golden blades look cool, LOL, :)

Alot of info to absorb but you'll have it down in no time.

-Josh
 
Josh Dabney said:
I appologize for being misleading here.

Tempering can done in the kitchen oven with fine and repeatable results as long as your aware of you need to check the temp with an actual thermometer. I did it this way for a long time.

Get one of these to hang on the rack inside the oven-
http://www.walmart.com/ip/Mainstays-Oven-Thermometer-00620W2/14913167

I think they're about $4.99 at walmart

I PREFER to use the Evenheat for tempering due to accuracy and repeatability of the temp. but fine results can be had with a conventional oven as well.

Let the blade cool to room temp after the quench then at least give it a good cleaning with hot water and dishsoap to get any oil residue off the blade. I like to clean one side up on the grinder to nice shiny steel so I can see the color I've got after tempering. If your plate quenching A2 in foil this will only require a light going over with sandpaper by hand to get clean steel.

I don't do this because color is necessarily an accurate indication of hardness but just to check for a red flag like a purple blade. And golden blades look cool, LOL, :)

Alot of info to absorb but you'll have it down in no time.

-Josh
Click to expand...


Ok, thanks man. I will keep an eye out for that thermometer next time I'm at walmart. It's good to know I don't have to be in a big hurry to get the blade into the oven after quenching.

My Grizzly grinder showed up today too. It is WAY bigger than I expected. Looking at the pictures of it online I thought the motor housing looked about the same size as the motor on my little bench grinder. Well it's probably at least 40% bigger.

I spent the afternoon re-organizing my shop to make room for the kiln. I covered a corner of the shop with wonderboard and made a little pedestal to put the kiln on so it will have a spark and heat resistant area. I'm unfortunately going to need to relocate my bench vise and my drill press to make room for the belt grinder. The drill press is a tool I use a LOT, but I think I might be able to put it on top of a rolling toolbox to make some room. I also have a table saw that I'm going to have to do something with as well. It's small and light, but bulky, and I can't afford the space it takes up right now. I thought I'd want it for cutting handle materials but I might be better suited getting a band saw that can cut both wood and metal.
 
Well, you're well on your way! Keep the drill press handy. You'll use it for every knife. Remember to keep a container of water/baking soda solution to cool the blade while grinding. A Grizzly will get the steel red hot in no time. Actually, I just use a pail placed on a stool under where I grind. This catches the "grindings" and is convenient to dunk the blade.

I use a table saw to cut scales from blocks of African Blackwood, leadwood or whatever else. I really think that you will find that cutting 1/8" annealed O1 with a decent hacksaw is pretty quick and easy. Cutting it is kinda like throwing hang grenades as long as you don't cross your profile. The really precise profile will come from grinding on the Grizzly. If you want a tight radius the small sanding drums that are used with a drill press are helpful. I can't think of the proper name but they look like spools of thread that you fit the disposable sanding "drum" over.
 
Well, looks like I might have run into a little setback. I assembled and mounted the Grizzly grinder, and powered it up for a test run.

When it powers on, there's a "click" sound coming from the motor housing and then it seems to run just fine. Once I turn the power off, it slows down. When it reaches a certain slower speed, there is a strange metallic scraping sound until the motor comes to a complete stop.

To me, it sounds like there is a part on the inside of the motor housing (perhaps the fan) that is loose. When I turn on the motor, it quickly tightens itself, and when the motor slows to a certain speed, that part's inertia overcomes the slowing speed of the motor and it unscrews and spins loose on the shaft.

This would account for the click on startup, and the continual scrape after it's shut down.

So, I'll have to waste a couple of hours disassembling it and un-mounting it from my bench in order to find the problem and coat it with loctite.

The platen looks like it's coated in automotive brake pad material. And the tool rest doesn't line up perfectly square. Still, I have another Grizzly machine so I knew it was going to need a little wrenching before it was ready to go.

On a more positive note, my carbide scribe showed up today.
 
That must be disappointing...if you can't get it to work right, you may want to consider returning it. If you want variable speed there are a number of other options.
 
Sticks said:
That must be disappointing...if you can't get it to work right, you may want to consider returning it. If you want variable speed there are a number of other options.
Click to expand...

Apparently I'm just stupid. I pulled apart the motor housing and there's some kind of centrifugal clutch in there that was operating normally and I mistook it for a defect! :shush:
 
It's all in learning to use what you have. I met a bladesmith who earned both his Journeyman's stamp and his Master's stamp with two Grizzly's. As mentioned they run a little on the fast side so cool your heat treated blades often and don't wear gloves. First, you can get the gloves caught between the belt and the rest and second, they keep you from feeling when the steel is getting overheated.

Doug
 
Thanks for all the help so far!

I started grinding my first knife today and had a heck of a time with the belt wandering all over the platen. Is there anything that can be done to keep it steady?
 
Can you add tension to the belt. I think belt wander usually results from the belt being too "loose" on the wheels.
 
Sticks said:
Can you add tension to the belt. I think belt wander usually results from the belt being too "loose" on the wheels.
Click to expand...

I've got it adjusted so the tension spring is almost fully compressed with the belt on. I might need to go ahead and try the glass platen liner or something.

I've read that some folks like to track the belt 1/8" to 1/4" off the side of the platen and/or contact wheel to make smoothly rounded plunges or to reach inside curves. I've tried that and it still made the belt wander all over the place.

I popped a 150 grit belt (cheap grizzly belt) today and about jumped out of my skin but fortunately no harm done.

Also, can belts be stored on the machine or is it best to take tension off the belts when not in use?
 
I would take the tension off the belt. It's possible that leaving the belt tight could cause the drive wheel to go out of round.

Doug
 
Doug Lester said:
I would take the tension off the belt. It's possible that leaving the belt tight could cause the drive wheel to go out of round.

Doug
Click to expand...

I'll loosen it some. But I still need to figure out what to do to fix the tracking. I've searched around and found a lot of people recommending electrical tape around the crown of the tracking wheel. I haven't tried that yet but that will be the first thing I try after giving the belt a little less pressure.
 
Petrified-

I couldn't imagine you need LESS tension or pressure.

If running properly the belt should track fine reguardless of how much pressure you put against it. In fact- grinding with light pressure wears out belts while accomplishing very little actual grinding.

I put as MUCH belt tension as I can realistically get for grinding blades.

1. Put on your belt and turn on the machine (without trying to grind anything) If the belt tracks true without alot of floating or side to side wobble and you can adjust the tracking so the belt will run 1/4" off one side of the platen then adjust it so it's 1/4" off the other side then your machine is working properly and tracking is NOT the problem.

Not being familiar with your grinder I had to reference the owners manual on Grizzly's website. I'm looking at page 22 & 23 of the manual- on how to adjust the sanding arm assembly-

If your spring is near maxed out you need to raise the sanding arm assembly to get more belt tension.

If the belt tracks straight until you put a piece of steel against it then goes all squirrelly on you- you need more belt tension. EDITED to say- not only more tension but ALOT more ;)

Hope this helps- Josh
 
Josh Dabney said:
Petrified-

I couldn't imagine you need LESS tension or pressure.

If running properly the belt should track fine reguardless of how much pressure you put against it. In fact- grinding with light pressure wears out belts while accomplishing very little actual grinding.

I put as MUCH belt tension as I can realistically get for grinding blades.

1. Put on your belt and turn on the machine (without trying to grind anything) If the belt tracks true without alot of floating or side to side wobble and you can adjust the tracking so the belt will run 1/4" off one side of the platen then adjust it so it's 1/4" off the other side then your machine is working properly and tracking is NOT the problem.

Not being familiar with your grinder I had to reference the owners manual on Grizzly's website. I'm looking at page 22 & 23 of the manual- on how to adjust the sanding arm assembly-

If your spring is near maxed out you need to raise the sanding arm assembly to get more belt tension.

If the belt tracks straight until you put a piece of steel against it then goes all squirrelly on you- you need more belt tension. EDITED to say- not only more tension but ALOT more ;)

Hope this helps- Josh
Click to expand...


Hmm...

I've got the tension set right now where the spring is almost fully compressed and the belt is a little tight going on the machine. The belt will track straight wherever I run it, but it begins to drift when I try to grind a blade blank. I'm wondering if the tension spring on my machine is too weak or something?
 
Sounds like you should be good on tension.

I'd try to see if I could make the belt "stall" (the belt stops turning but the contact wheel keeps turning) by ginding against it with alot of force. If you got a belt cleaner push the end flat agains the belt.

If the belt stalls- more tension
If the motor bogs down and slows the belt then tension should be sufficient and look at tracking.

-Josh
 
Josh Dabney said:
Sounds like you should be good on tension.

I'd try to see if I could make the belt "stall" (the belt stops turning but the contact wheel keeps turning) by ginding against it with alot of force. If you got a belt cleaner push the end flat agains the belt.

If the belt stalls- more tension
If the motor bogs down and slows the belt then tension should be sufficient and look at tracking.

-Josh
Click to expand...

Thanks for the tip. I will try that and see where to go from there.
 
Ok, I lengthened the arm about another 5/8" or so and the belt is as tight as it's going to get. I added 2 layers of electrical tape to the center of the idle/tracking wheel and that has made a big improvement, but it still drifts away from the plunge line when I apply the blade to the platen.
 
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