I have a 6″ delta bench grinder and it run 3450 rpm–So here is the question—I have some parts cleaning to do with a nylon disk–Alum motor parts….Can I wire a rotory dimmer to a plug and run the speed down so I can safetly clean the parts without the excess speed. I can just hear it now—-What! Are you nuts?
I am just brainstorming and this won’t be a permanant attachment. I am just wondering if I will hurt the grinder or worse –burn it out.
thanks Mike
Replies
dimmer won't do it but a variac will but the motor is at risk..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
I am guessing that it might work so do more research before using this. I have an external router speed control. I paid 70 bucks or so thru tool crib but I see Harbor freight sells a knockoff for less than 20 bucks. The router seems to literally switch on and off when it is set at its slowest setting.
Karl
Imerc. is what Karl talking about the same thing as you are mentioning ( vari-ac)? Isn't that how a dimmer works on a incondecent bulb--By turning it off and on quickly to achieve the dimmed affect?I am in the dark on how you can regulate motor speed other than turning it off and on---I find it interesting than my Dremel (R) has vari speed and it is a dinky little thing that in the right circumstance comes in mighty handy. But I wonder------lost-----thinking to myself------How?-------How?-----how can this work, Hense I am a carpenter and not an electrical engineer.
there are so many kinds of motors that it isn't funny... and they all look alike...
frequency controllers or voltage reostats are a couple of ways to control a motor(s)...
it's all in how the motors are wound, the field is bunnied ... er.. energized... their poles... phasing or split phasing.. or... or... or...
you get the idea...
yur drill motor is a world different from the motor in yur table saw... not the same beast.. now that I want to tell you the difference CRS snags my butt... so bear with me...
A motor controller will only change motor speed by a few percentage points...
yur VS drill or any other VS power tool is built to do that... go variable speed.. that 3450 you have - isn't... drop the voltage and you will get a massive heat build up in short order... cookin' the motor while yur at it..
change the freq and you get speed change at the cost of burning out the field...
so you could trash yur motor either way...
a variac is a tade off of both worlds... but you will still garbage yur motor after a while of use..
so....
go get you a multi-speed definite purpose motor with a controller switch and get everything ya want ...
but that's $$$$$$$$$
or...
rig a stepped pulley and a pillow blocked shaft to get a mechanical speed change..
or...
go to HF and get a drill chuck mountable left hand threaded shaft to fit yur polishing wheels or what ever it is you want to turn and yur drill chuck size and get a universal drill mount / holder.. Mount yur VS drill... chuck up what ya want.. set the speed yur looking for... go for it...
this is the cheapest way...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Edited 3/9/2005 2:34 pm ET by IMERC
Assuming the drill is reversible, just orient it so the chuck doesn't unscrew and it should work. Otherwise, setting up the shaft with pillow blocks/pulleys, etc will definitely work. If the pulley is stepped, you could even make it into a low speed grinder for sharpening chisels and plane irons. (This is where I repeatedly kick myself in the butt for tossing a setup that would have worked for exactly what we're talking about, but needed some work)
"I cut this piece four times and it's still too short."
A variac won't work practically.All it does is drop the supply voltage.Now you will get more slip and thus slower, but not by much and you will loose all torque. So it will stall just getting a blade 3" from the grinding wheel.Now a VFD/VSD (variable speed or frenquency drive) will work. But I don't know of any designed for single phase so I am not sure how well it work work in this case.But it would be like using a horwizter to shoo away a fly.
Wow--now I know why I am a carpenter .....Ever since physics class with the magenet and wire motor I haven't learned much about the guts of a motor just what it can do.You bring up a great point about the universal mount. I hve an old Craftman 1/2 VS drill that has a lock on trigger that I could work something out with.We have a place called Northern Hydralics around these parts I may be able to find what I need. Thanks---You got the juice flowing on how to solve this w/ o the grinder. MikeCRS=Prior service?
Edited 3/10/2005 2:06 pm ET by mitremike
NH will have what you want... and then some...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Ya could pully the grinder to the drill motor and solve the grinding / polihing wheel attachment right off...
belt the drill to a pulley on the grinder.. just run the belt over the outside of the drill chuck...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Mike,
As others have said the dimmer route will kill your motor.
I bought one of these a couple of years ago and am quite happy with it...
http://www.deltawoodworking.com/index.asp?e=136&p=5864
On a hill by the harbour
Novy---Funny thing is is that this is exactly what I need and what I wanted when I bought my regular one a few years back.Sure enough a short time later they released it . After I allready bought the reg. one.Imerc got me going on using an old drill and a pulley mount that " just might be crazy enough to work"Thanks, MikeP.S. Wanna trade? LOL
You have an induction motor on the grinder, you will destroy the motor if you try to slow it down with a speed contol. There is a simple solution, I also have a 3450 rpm grinder. When I grind lathe tools I turn the motor on, let it come up to full speed and shut it off. I grind til the stone stops, usually one time maybe twice will suffice. I do not know how long it would take to buff the aluminum, try it , can't do any harm.
mike
Thanks to all for your input---I have some slow speed,tedious cleaning to do on these alum. parts and I have come to the conclusion that the way to go is chuck a pulley in the drill-- 1250 rpms and reduce the pulley on the grinder ( using it as nothing more than an axel with mass to hold the cleaning wheel) then I can run the drill on full as not to burn out the variable on the switch. A trip to northern outa do --beside any time I get to build something for myself I'm all for it.Of course it may be a good reason to get a vari grinder but why buy something when you can build it. Side note to Imerc--If you like the mitersaw stand I built just wait and see the Radial saw rolling cabinet I built under a older Dewalt that I got at an estate sale---Of course I'll have to wait till spring to open the garage cause I don't need to start another ruckes about those "pink cabinets"Thanks to all for your help. Mike
You'll be going to more trouble than you need to...Go get that old 1/3 hp washer motor that you scrounged and stashed somewhere.Now go to NH and get an arbor adaptor for the shaft on the motor.Plainly stated, it slips onto the shaft on the motor, and is held tight by two allen screws.The end of this is an arbor that you can mount your polishing wheel to. (Threaded, with two real thick washers, and a nut...)Put your polishing wheel on it, and leave it there forever.1750 rpm. Half the speed of your grinder.
The person you offend today, may have been your best friend tomorrow It is easy to be friends with someone you always agree with.
Luka--How did you know I have a washer motor? I even forgot I had one till you reminded me. Score, Bonus off to NH I go. Good thing you reminded me--Now if you could just tell me where I put it that would be great.I was kinda looking forward to putting the old Craftsman to work again but I guess it will just have to stay put for now.If you can't remember where I put it do you think the wife will mind if I borrow hers.LOLthanks Luka. MIke
It's under a bench, or inside a lower cabinet or something. Shoved back in the corner. Other stuff in front of it, hiding it.Drag it out before you go, because you will need to know the shaft diameter.It'll likely be 1/2" or 9/16".
The person you offend today, may have been your best friend tomorrow It is easy to be friends with someone you always agree with.
Here is the type of arbor I am talking about.http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46622
The person you offend today, may have been your best friend tomorrow It is easy to be friends with someone you always agree with.
that is exactlly what I need and did manage to pick one up at a place called Northern Equipment ( at least around these parts)Harbor freight opened a store in the north metro about 25 miles but haven;t had good reason to head up that way.So I got the motor out and mounted it to a piece of ply --installed the spindle and now the hard part,Wiring that mess of harness into a simple on/off--I started on it and removed about half the wires and now I am in the head scratching mode, fortunitly I cut the diagram off the back of the machine and i just need to sort it out, probely 6-7 wires coming out ot the motor housing and a capasitor(sp) Certain satisfaction making something from nothing.Glad you are looking out for me, Mike" I reject your reality and substitute my own"
Adam Savage---Mythbusters
Good idea on the washer motor. I've a sump pump that also runs at 1750rpm...
Luka, could you please advise on the optimal speed at which to run a 6" grindstone? I've a new white Norton, coarse, rated at 3820rpm, and I want to quickly restore a bevel on wood chisels. Should I run it 1-to-1 off my sump pump motor?
BTW, I've not started on the zero-clearance insert yet....waiting to spear myself with a kickback first. LOL
I really have no idea what speed you should use. Art Brockschmidt, (Junkhound), is likely to have the answer to that one.I would just run it on that arbor, directly on the motor and see how well that works.If that doesn't work, you can always get a pillow block, and a couple of step pulleys to step the speed up or down. Do that until you discover the optimal speed for yourself.It may be rated for 3820, but that does not make 3820 the optimal speed for your use.You run the stone too fast, and you can easily ruin your chisel with the heat.The old grindstones only went as fast as someone could crank or pedal them.---No explanation needed. I "research" my projects far in advance, myself. Like the bandsaw that will probably take me two or three years to be ready to rebuild. Or the well I may put in, or develop the spring, don't know which yet. Or cabin plans for a cabin I may build, or may not. Probably will...Many things just turn out much better if you give them time to jell in your head. Think about them. Forget about them. Remember them, and research. Forget again. Finally just do it. And you are a lot more ready to do it well, by that time. Not just kludge or bodge it together.
The person you offend today, may have been your best friend tomorrow It is easy to be friends with someone you always agree with.
I like your idea of letting the project start itself when it knows you're good and ready to carry it out successfully. Picking a cabin site is definitely something to ponder awhile.