The slow speed grinder mantra - kinda O.T.

Re: The slow speed grinder mantra - kinda O.T.

Bob Hackett

>For less than $80 you can get one of those mandrels,arbors,grinding heads,etc(see below under what`s it called)and a used motor and with your metalworking skills cobble up pretty much exactly what you want and still have money left over to buy the diamond and hardware for one of Sir William`s wheel dressers.

That being said,I see no real advantage in a low speed grinder.If you`re going to be ham handed enough to burn at 3000 RPM then you`ll probably burn at 1500 too.I learned how to grind tool bits on a regular 3400 tool room grinder and the fellows that showed me had been grinding high carbon steel on it for years without burning.The key words are skill and patience.

I`d stay away from 2 speed grinders and especially the variable speed models.They tend to go toes up at about half the life of the single speed.

The turning forum has numerous grinding posts in the archives.Best tip on buying a new grinder?Look for an old,well made one at a flea market or garage sale and add attachments.The Baldor I have cost me $20 talked down from $25.

Mainely,Bob

a virtue of slow speed

bill tindall

>I do the first step of sharpening on a grinder. That means I am grinding to establish a fresh edge and therefore grinding to the edge. With the proper wheel, burning is not an issue( see extensive earlier discussion on the topic) BUT control can be when working at the edge. With my wheel and 3600 rpm metal goes away at an breathtaking rate. A grinder that turned much slower would provide me greater control, yet grind to the edge at a satisfactory rate.

For initially shaping tools, for example a new lathe gouge, the 3600 rpm is desirable if coupled to a proper cool grinding wheel.

Physics--not just a good idea--it's the LAW

Jim Reed @ Tallahassee

>The virtues of low speed grinders are HIGHLY overmarketed. Apply the laws of physics to dispell all the vendor claims. Burning is caused by too much pressure, too much time in contact, poor quality wheel, non dressed wheel, operator error, etc. Speed of grinder just does not come into play at a high level of importance.

My last grinder was new from Costco (Wilton 6" for $29). I have ground three wheels down to nubbins and it is still going strong. Use the cheap wheels for rough grinding and buy some good white or pink wheels for your tools. I swear by my Wolverine (use it at least ten hours a week) and do not see how you could build one for the $80. You must have some really good metalworking skills. Good luck with your grinder.

Wheels & Speeds

Frank Mutchler in Colorado Springs

>Ken, Oneway offers different grinding wheels that are designed for either 1725rpm or 3450rpm grinders. I don't know all the specifics and really don't have time to dig into all the data regarding wheel composition & speeds, etc. so I've decided to trust their judgement.

Bill has chimed in on this thread and he does seem to have studied the subject in depth.

Re: Physics--not just a good idea--it's the LAW

kenc

>Jim,

No, my metalworking skills are average at best, but I am enthusisitic. The only part I had to pay for was the 1" square tube and some 1-1/4" "nested" tubing into which the 1" fits. This stuff is welded on the corner rather than the flats so that the weld doesn't interfere with the sliding fit. Other than that it was scrap or steel that I had on hand so my total cost was quite low. However, I think you mistook my meaning - I was saying that I considwer the wolverine to be an EXCELLEMT value considering the time I took to make one. I shall make the vari-grind attachment next.

Ken

Re: The slow speed grinder mantra - kinda O.T.

Jay Samuels

>As posted last Friday, I picked up an old 10" water drip slow speed Dunlap grinder on the way to work last week. I haven't put the speed gauge on it yet, but its really slow, probably a little too slow. Here's my take: It's great for gouges and carving tools. The metal comes off nice and slow, no burning and no endless regrinding because you took too much off one side. It's not agressive enough for regrinding chisel bevels or likely plane irons, although I have not tried one. It seems to me like your other equipment probably covers the field already, but we all know you can never have too much equipment.

Love my Tormek

jim reed @ Tallahassee

>It is slooww also. Slow is not bad if you set it up in front of the tv.