buffing

Jack142

Jack142

Joined
Aug 26, 2002
Messages
433
I need a little bit of advice. I just got a used craftsman 3750 rpm motor with a belt that attaches a grinding wheel. Actually it is 2 hard 60 grit grinding stones with a pulley in the middle. All set up and welded to a heavy and I do mean heavy metal frame.The cost was 50 bucks.
Now I want to take the grinding wheels off and put buffing wheels on. So is 3750 rpm ok to buff on, or is it too fast ?
If I have to slow it down what kind of pulley wheels should I get ?
What kind of buffing wheels do you guys recommend ?
what about compound ? what kinds would you recommend ?
Any other suggestions you can make would be appreciated.
Thanks
Jack
 
3750 RPM,is a very high speed and very dangerous.Buffing is
the machine that will hurt you faster than you can blink.
If I was you I would try to slow it down,buffing just makes me nervous:eek: :eek:
 
3750 is fairly high but will work well if you limit the buff diameter to 6", this will give you about 5000 surface feet per minute, ideal for buffing metals.

Take care if you have never buffed before, and get some hands on instruction. Buffers are dangerous.
 
1800 rpm with an 8" buff wheel is pretty average.
That means you need a pully half the size you currently are using to slow your buff speed down by half. Local farm supply store or electric motor repair place will have pullys.
Then you can use 8" buff wheels.

Some guys use 10" wheels (this is faster surface speed) and some use 3600 rpm motors with smaller wheels with out any problems. 1800rpm is fast enough for me. I've had one pull out of my hand. It'll scare the bejeebers out of you.

Try 1"wide stitched cotton buffs to begin with. I'm guessing you are going to do stainless so get a green chrome (grease based) bar and a pink (grease based but it's very dry) no scratch bar of compound. Use the green first to smear out the final scratches, use the pink to clear up the cloudy residue.

All of the knive supply places will have these with some variation in brands. Each buff wheel should be dedicated to one buff compound so get at least a couple.

Have fun...
 
Be careful! That buffing wheel spends all its time trying to grab the work piece so it can sling it. Keep knife edges and points pointing toward the direction of rotation so the wheel can't grab it. Practice carefully.

I was advised to keep my buff speeds down to around 1800.

Roger
 
thanks for the advice on the buffing speed and compounds. I intend to look around for a differant pulley for the motor.
I got another question. I picked up a piece of steel at home depot to practice grinding on. It has a label on it that said it is welding steel.
It's pretty soft and easy to drill into.
Does anybody know what kind of steel it might be ?
I really got it to practice bevels on, BUT if by chance a blade comes up looking pretty good Can I heat treat this steel and come back with a decent knife ?
Again thanks for the advice
Jack
 
Jack, that is mystery steel (whatever they had went into the pot) and it won't harden up. O1 or 5160 steel is probably only pennies more than the 'weldable' stuff so when you grind a knife - and you will - you can do something with it. As long as you have steel left to grind, you still have hope of making a knife out of it. It may be quite a bit smaller than when you started, but you can make a knife. Some one locally will have some O1 or 5160 you can pick up.
You'll put more into it if you think you can get a knife out of it rather than knowing you can't do anything with it and it's heading for the trash can. That is worth the few bucks you'll save by using the soft steel.
 
TMICKLEY, Thanks for the advice on the steel.
I got another question.
I looked at harbor freight and thier buffers. They all are 3400 rpm or better. If buffing works ok at 1800 rpm and is safer; then why do they make all of them at 3400 or better ?
Look I am no expert. I just started doing this a couple of months ago.I have only made 4 knife kits. I bought the kits; reground the blades to shapes that I liked and put handles on them. I been using files dremel tools and lots of sandpaper I go though 220 like toilet paper.
I have a cheapo grinder. I usually use it for doing my wood working stuff. I find that its ok for the rough work, but I do better going slower and doing a lot by hand at the end. I figure buffing is the same way. Slower is less room for error and safer.
Anyway I gotta go thank again gang for the advice. Boy I do like this site
Jack
 
TMICKLEY, Thanks for the advice on the steel.
I got another question.
I looked at harbor freight and thier buffers. They all are 3400 rpm or better. If buffing works ok at 1800 rpm and is safer; then why do they make all of them at 3400 or better ?
Look I am no expert. I just started doing this a couple of months ago.I have only made 4 knife kits. I bought the kits; reground the blades to shapes that I liked and put handles on them. I been using files dremel tools and lots of sandpaper I go though 220 like toilet paper.
I have a cheapo grinder. I usually use it for doing my wood working stuff. I find that its ok for the rough work, but I do better going slower and doing a lot by hand at the end. I figure buffing is the same way. Slower is less room for error and safer.
Anyway I gotta go thank again gang for the advice. Boy I do like this site
Jack
 
Jack
Here is somtihng I do for buffers,I got regular bench grinder
and took the wheels of them and bought,arbors for the shaft
They can be purchased form most knife suppliers.You can get into some top dollar for buffer.you can get a bench grinder from ebay for 20 bucks or so.Check the RPM on them,you can find some in 1725
1600,There is an idea that will save you some extra money.All my
buffers are made tht way and they work fine;)
 
I don't know why but I experienced the same as I look at off-the-shelf buffers at local stores. They seem to all be high RPM. I guess they aren't thinking of knife buffing. - DANGER - . I use a motor speed control on mine. I will probably ruin the induction motor eventually but for the price I paid at Harbor Freight I don't care. Even at slower speeds it is a religious experience for me to buff a sharpened knife. I do it though. :eek:

Roger
 
Jack, one other thing that you should do is keep each buffing
wheel in a sealed bag, because the cloth can easily be contaminated
with grit that can scratch your steel and ruin the buffing wheel.
 
In buffing RPM is only part of the formula. In order to buff metals you will need a minimum of 5000 surface feet per minute where the metal meets the buff. You can achieve this by any combination of buff diameter and motor RPM using the formula SFM=RPM X Buff circumferance(in ft).

It doesn't make any difference to the metal/buff interface what RPM the motor speed is because simply doubling the buff diameter doubles the SFM or the other way around.

The only problem is a psychological one, the higher RPM motors sound more dangerous.
 
not quite as technical as george, but most buffing machines are made in either 1800 or 3750, for good reason, you need high speed to properly buff many metals, not so with wood etc. If you want to slow it down you can get a 1750 motor, or as you said, get a smaller pulley for the motor side, but I have had a baldor 3600 for almost 20 years and use it every day.

All machines are dangerous!!! I have been hurt on my drill press more times than I can count, and although the buffer goes quite fast, if you pay attention to what you are doing you will be fine.
 
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