Which Buffer and What Speed??

D

Diamond G Knives

Well-Known Member
Well Im now looking at a biffer. What brands are good these days? (cant afford Baldor yet) Looking for an off shore. Grizz has gone WAY up! Last I bought from them was $68 on sale for a 3/4 hp! now they are $299! (Guess Im getting old!)

Anyway, what brands seem to work for you folks? What speed seems to work best?

Im more comfortable with a 4 or 6" wheel, dont like the big ones.

Appreciate your thoughts.

God Bless
Mike
 
Rod Nielsen has made some disks for his Interchangeable Disk System which he has glued a disk of bathroom shag carpet to and uses as a buffer. I have one and it works great and does not try to grab your knife, or whatever, and throw it back at you or across the room. And the bath mat is cheap and you get lots of disks out of one mat.

I have the disk systems so you can get a buffer and a disk grinder, all in one and with the Interchangeable Disk System you can change from buffer to grinder easily.
 
You can always go the DIY route. Right now I use my wood lathe with an aftermarket buffer system that works well but in a pinch, all you need is a motor ( you can find one for about 50.00 new from the folks I referred you to) shives, some threaded rod, pillow blocks, plywood and time. I run 4 wheels at once on the one that I have and saves quite a bit of time and I've built a "hood," over it to keep from having things launched at me. I'll take pictures when I get around to cleaning up my unholy mess. (too many DIY projects at once.)

If you can get the sept. 2011 issue of ShopNotes (www.shopnotes.com) they have a "sharpening station," build that can easily be tweaked to be used as a buffing station. Its an easy build and pretty detailed.

And if you'd like, I can scan the building set up in exploded view. I'd post it on here but I think it may violate copyright laws. (it comes with a list of materials and hardware and cutting diagram.)
 
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6 to 8" wheels on something no faster than 1800rpms. Baldor is the industry standard, and most knifemakers like the 3/4hp version. Faster buffers have a tendency to burn things, and as the rpm goes up, the level of danger increases dramatically.

I actually have two buffers in my shop, a Jet 1hp, 1725 rpm, which is the one I most often use for knifemaking, simply because it has very long shafts/arbors that allow more room. My 3/4, 1800rpm Baldor is used with a super soft wire wheel for satin finishing and fine cleaning, and for use with a unitized (scotchbrite) wheel for specific folder making operations.
 
Yes, you can use a bench grinder. You will need to remove the guards and mount it to the edge of the bench (or a stand-alone pedestal) for best access.
Any bench grinder could work. If you don't already have one, even the cheapies at a place like Harbor Freight would work. This assumes you're not investing in the tool for actual grinding purposes; if you need a good bench grinder, then get a good bench grinder.

If you're wanting something specifically for buffing, but can't afford a "true" buffing machine, a bench mandrel may serve the purpose better than a bench grinder.
The issue is shaft length. On a converted bench grinder, you're limited on the approachable angles because the motor gets in the way unless you use the larger-diameter wheels. A mandrel would allow more access because the motor isn't in the way.

You asked about speeds.
It really depends on the material you're buffing. I like to use higher speeds whenever possible in order to get the job done quicker. But some materials won't tolerate high speed. Fortunately, most of the materials we use in knifemaking allow some overlap in speed selection. That allows us to keep the same speed for a variety of materials, meaning you're not constantly switching to a different wheel diameter.

Here is a range of speeds that seem to have provided the best results for me.
The reason there is a "range" is because not everyone applies the same pressure, and not everyone uses the same compound.
Since these are not exact, don't go overboard trying to obtain an exact speed. Just try to get in the general window of what has been proven to work well.
All speeds below are surface speeds (SFPM).
Stainless steel...................... 3500-5000
Steel.................................. 3500-7500
Copper, brass, etc.................3000-7000
Aluminum............................. 3500-7500
Titanium.............................. 1000-2500
Wood, plastics, finishes, etc... 1000-2500

Remember, these are surface speeds, not RPM.
So if you're using a wheel running at the same RPM as the motor (the case with your direct drive setup), you change the wheel diameter to change SFPM.

The typical bench grinder will have a motor speed of approximately 3450 RPM. So let's see what surface speeds you're gonna get by mounting different diameters of buffing wheels to it.
4" wheel....3613 SFPM
6" wheel....5419 SFPM
8" wheel....7226 SFPM

So you mentioned that you prefer 4" or 6" wheels. Coupling that to the typical bench grinder, you're covered for the metals. But you can't get in the window for best speeds on the handle materials, titanium bolsters, etc.
Many people have asked questions on why they can't get their Micarta, G-10, etc. to "look right". And there will be all sorts of answers. But I maintain the fact that most of us try to use a "universal" speed for the entire knife, when we would be better served using different speeds. Not the answer everyone wants for production, but it's the only answer for quality.

So that's why the motors on many of the "professional" buffing machines you look at have the lower speeds (1100 RPM is common).
The lower motor speed gives you increased flexibility regarding wheel size- it allows you to get those lower surface speeds without resorting to using a miniature wheel in a rotary tool.
But, as you've noticed, budget is always a concern. This is another reason why a mandrel may ultimately be better for you than a bench grinder. A 1725/1750/1800 RPM motor can then be used. Or even if you still use a 3400-3500 RPM motor, you can still use pulley reduction since the bench mandrel is not a direct drive setup.

As with everything else, the type of setup you use will be heavily influenced by the needs of your particular projects.
A person doing small items may not need the same access as a person doing larger stuff.
Likewise, some people don't delve too deeply into what's required for the "ultimate finish", so working within the optimum speed range isn't important to them. They simply say "it's buffed", and call it a day.
Only you can know what level of finish is needed for your work.


Good Luck,
Rob
 
If you're referring to the various shapes of felt bobs that are used in a die grinder, flexshaft, or other rotary tool, then, yes, I do use them. They are very handy when polishing objects with highly contoured surfaces. Roots blowers, intake manifolds, etc. Such items seem to always have surfaces not easily accessible with a wheel (no matter how small the wheel).

If you are referring to an actual felt wheel, I personally have never seen the need for one. I can't really think of an application where it would be superior to the materials already out there.
But I'm sure that, like everything else, it has its followers.
 
I bought a new dc controller from surplus supply for 150 dollars and was given a used dc motor that needed a 100 dollar rebuild. After hooking them up I have a variable speed buffer and a variable speed disc grinder that goes in both directions. That may be an option if you can find a cheap motor and dont mind wiring and such.
 
King is a good brand that ive never had trouble with and the price is decent I have a 3/4 and was like under 100 so if you want the best Baldor is a good brand and very poular too but very expensive. I forgot to mention I have a couple 1/2hp motormaster thats canadian tire a little to weak but sometimes good because stalling out might save a finger. Kellyw ps buffers are the most dangerous tool in the shop be careful
 
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