Bench Grinders for smithing and polishing...

[The Ozzman]

Hey again folks.

I am in the market for a good bench grinder....to polish gun frames for rebluing....for general smithing, sharpening and grinding.

So I am wondering if there are any caveats, reccomendations etc etc. Bear in mind I am in Australia so specific brands may vary.

I had a look at the harware store today...leaning towards the best brand I can afford and most powerful in terms of wattage.

I will be buying polishing pads, wire brushes and polishing compound later on. Tips on those are welcome...I wonder if Colt will loan me any of their old ones? lol

I guess I am asking; are all grinders made equal in terms of ease of attaching polishing wheels, flat wheels for knife sharpening etc.

Thanks for your time

Ozz

[Hickory]

I've made a few knives over the years and always wished for a slow turning, powerful outfit for polishing the blades, but I think 1780 rpm is the standard for most grinders.
If you could get an arbor and gear it to your desired speed and horsepower motor for the work needed, you might be in business.

[Jeff Michel]

Most grinders are 3600 RPM, buffers are different, longer shafts and generally speaking slower, 1800 RPM. You COULD use a conventional grinder with buffing wheels but only for small stuff. The reason for my hesitation is the safety factor. Change direction of the part or bump into the grinder frame due to lack of clearance, you increase the probability of the part being grabbed by the wheel. You will find you need both for working on stuff anyway, get both and save yourself the hassle of removing guards, wheels, etc. You haven't lived until you have had a barrel snatched out of your hands! Be safe and wear your respirator.

[Iron Whittler]

Good morning from S.W. Louisiana. You will need more than one . A buffer runs at 1750-1800 rpm shaft speed. A good one is the Baldor 3/4 hp double ended unit. It can use 8-10 inch buffing wheels. Very sturdy and reliable. I have had one for 15 yrs. and still going strong. It was used when I got it. For buffing and polishing, that is the one. For general grinding, wire brushing and smithing, an 8 or 10 inch will do nicely. these usually run a shaft speed of 3600rpm. Jet tools make a good one. As for knife sharpening, get a Worksharp Ken onion edition + the knife and tool sharpener attachment. The whole kit can be had on ebay for around 250-275. comes with all needed belts and instructions. With a little practice, the edge will be sharp enough to split frog hair. As for buffing wheels, polishing compounds, soft wire wheels for carding, Brownnells is my first choice folled by Jantz knife making supply. Either of these two companys can ship to you. Good hunting for your equipment. Best wishes.. Iron Whittler:drinks:

[The Ozzman]

Guys that has been very helpful!

I will indeed be getting a dedicated buffer now for certain. As well as a dedicated grinder.

Very pleased to know this, otherwise I would have been very frustrated! I will check back in here in case anyone else chimes in. I am now off to look for bench mounted buffers!

Thanks!!

[The Ozzman]

I am looking at what is available here in Au.

A little bit limited it would seem but I have found a polishing website. There is a 1/2hp 6 inch polisher that runs at 2590rpm.....is that RPM too high? It is within my price range.

Cheers

[smokeywolf]

Reason for the 1800 RPM on the buffers (mine's a 50+ year old Baldor) is higher RPMs causes the buffing wheel to heat the surface of your part too fast. Plus, not sure about this, but you may find that some of the buffing wheels aren't rated for anything over 2,000 RPM.

[Iron Whittler]

As an after thought, you can build your own. Used elect. motors driving SHAFT BY BELT AND PULLEYS. shaft speed can be adjusted by size of belt pulleys. Pillow block bearings, precision size shafting, and pulleys avail on Ebay for good prices. Motor size 3/4 or 1hp. Motor speed is no matter as pulley sizes will determine shaft speed. You may be able to locate a used motor around your area for cheap. Square tubing or angle iron for frame work. Easy fab job if you weld or know someone who does. Just something to chew on.:drinks:

[johnnylawless]

Look into Tormek they have really nice stuff.

[Jeff Michel]

As to buffers.... Do not get a 6" buffer. Look for something that will handle 8" minimum, 1 to 1 1/2 HP. Anything smaller will probably stall if you do a barrel. There is a lot more drag than you may suspect. You might consider a fine wire wheel. I use it (oiled) to blends polishing scratches at 150 to 180 grit. Comes very close to a factory finish.

[country gent]

A true buffer has longer noses on the spindles to help keep the parts away from the motor and give more room to work. A true cotton buffing whell on one side and a sisal or heavy felt whell on the other side for first pass or rough polishing speeds things up alot. also by a buffer rake to clean and true wheels helps alot also.

[Duckiller]

Cheap grinders = 3600rpm. Good grinders = 1800 rpm. 1800 rpm grinders cost a lot more. They don't overheat things.

[yovinny]

One word; Baldor

Buy once, cry once.

[The Ozzman]

Thanks guys. I think I will be saving up and going with the top notch low RPM versions you reccomended. I have long stopped buying cheap junk just to get it quicker. Sounds like a polisher is far more specialised than I had thought.

My first project is to refinish my trapdoor to original armoury bright. It has minor pitting but I can live with that. I have done a bit by hand, polishing compound and light sandpaper on the localised rust patches. Also used a hand held wire brush on them....probably not the best idea but it worked.

Very excited to get her looking good and working again. A gentleman in the US makes repro stocks....so I will not be touching this original one....cartouches are very light and possible initials hand carved would be obliterated.

Will keep you posted.
As always, my sincere thanks

Ozz

[lightload]

I don't use a grinder. In my reading I've noticed mention of the need to true a wheel and recently saw items at Sears for this process. How important is this?

[bangerjim]

Slow speed ~1700RPM. 3600 just burns stuff up. Good for grinding and buffing. Slow and easy is the ticket.

Baldor if you can find it. Like said....buy one once in a lifetime. I have 3 of them and my sons will inherit them! Do not buy HF gunk if they even sell it down under.

A also use a 12x2" water wetted VERY slow RPM stone for precision grinding. Reminds me of the old treadle stone my granddad had up on the farm!

Truing a stone is key in getting good tools made. I use a 3/4ct diamond dresser that slides back & forth on the face of my stones (AlO2 and "green"). when I need to true them. Otherwise you get valleys and crowns in the surface that give you carp finishes when you grind your stuff. Those "star" wheel dressers are for carp. Don't waste your money. Diamond is the only way to go.

If you put a wire wheel on one side, be sure you buy QUALITY industrial grade (SST if you can find them). Cheeeeep ones throw wires all over the place and you will be picking out of your legs and shoes!

ALWAYS ALWAYS use the guards that are on the grinder!!!!! And the rests also. NEVER grind on the sides of a stone or composite wheel!!!! I have diamond covered steel plate wheels I do that on, but NOT stones/wheels.

NO grinder?!?!?!?!?!? OMG! That was the 1st tool I bought decades ago when outfitting my 1st shop out of college. And it IS a Baldor!

banger

[abunaitoo]

Sears has a variable speed bench grinder.
I've never tried it.
I already have a high and a low speed grinder.

[Silverboolit]

An expandable sanding drum is excellent for doing flat work. Can get belts up to 2000 grit.

[izzyjoe]

Not changing the subject, but those guards will save you're face in the event a grinder stone blows up! And scare a few years off you're life.

[Kilroy08]

I'm firmly in the big wheel, slow spindle camp.

I have an ancient 6" Speedway bench grinder, it's fine for light grinding. For serious work, I would love to have something low speed with a 2" wide 12" diameter stone on it.

[Dragonheart]

I think building your own is the best route, but you have to have the knowhow and the tools. You can save some money and get exactly what you want.