Reversing chain grinder

[Patrick62]

I set up my el-cheapo (nick the grinder) to reverse this evening. Piece of cake. Motor is a permanant magnet type with brushes. Okay, that means that they are running it on DC! Closer inspection of the on/off switch revealed a full wave rectifier.

Drill out a couple of holes for the wires to come out, and mount a double pole - double throw switch. Wire it up like this:

connect the common terminals to the power supply.
Connect the motor to one end of the switch
Connect the other end to the motor terminals with the leads reversed.

You now have a switch that will run the motor in foreward for one side of the chain, and reverse for the other side!!!!

Then I sharpened a couple of loops, and the result looks great!
In spite of all of this, I am still gonna get me a Oregon 511 eventually.

-Pat

 

[danl]

Patrick

I have a Nick Grinder also, although I wouldn't admit until now.
I just use it if I hit a rock, fence or something. Normally I hand file.

Harbor freight doesn't carry them anymore. Where do you get your grinding wheels. I ordered a extra when I bought mine and they backordered it and never shipped it.
I would like to reverse mine also.
How hard would it be for you to draw that out, to make sure I don't toast something.
Dan

 

[xander9727]

A pic would help.

 

[lostone]

Patrick

I have a Nick Grinder also, although I wouldn't admit until now.
I just use it if I hit a rock, fence or something. Normally I hand file.

Harbor freight doesn't carry them anymore. Where do you get your grinding wheels. I ordered a extra when I bought mine and they backordered it and never shipped it.
I would like to reverse mine also.
How hard would it be for you to draw that out, to make sure I don't toast something.
Dan

There site still has them, they must have forgotten to update it and take them off of it. Nick grinder
also they say they have these wheels for them (they are 3/16" larger in diameter than the nick wheels but are 1/3 the cost if they will fit the nick grinder.
I am wanting to get a nicer grinder, I bought one of the harbor freight specials and it started running backwards on its own (dont know why it ran fine the first time I used it then ran the wrong way after that) I took the cover off and reversed the wires once I seen it was DC motor in there and it has worked fine once the wires where reversed, I use it to even the teeth and clean up a chain if it hits a rock or something then finish them off with a file. Its not much but is better than nothing on saving time to even the teeth out.

 

[Simonizer]

I set up my el-cheapo (nick the grinder) to reverse this evening. Piece of cake. Motor is a permanant magnet type with brushes. Okay, that means that they are running it on DC! Closer inspection of the on/off switch revealed a full wave rectifier.

Drill out a couple of holes for the wires to come out, and mount a double pole - double throw switch. Wire it up like this:

connect the common terminals to the power supply.
Connect the motor to one end of the switch
Connect the other end to the motor terminals with the leads reversed.

You now have a switch that will run the motor in foreward for one side of the chain, and reverse for the other side!!!!

Then I sharpened a couple of loops, and the result looks great!
In spite of all of this, I am still gonna get me a Oregon 511 eventually.

-Pat

Hey, you are not your average Bozo. Most people think a full-wave bridge is a device for spanning ditches in the event of a hurricane. On that motor you could make it two-speed if you supplied half-wave rectification with another switch. Cheers.

 

[Patrick62]

That could work, but why?

Slow it down?? I could plug it into the variac and turn it from a snail pace to overdrive!! I will have to figure out a way to draw it out, but it really is fairly simple, but one must remember we are working with 150V DC here...

Any grinder that has a permanant magnet motor is candidate for reversal. The advantage is that the burr is now into the tooth rather than outside the left cutters. I cut a little with a chain sharpened this way today, and there is a noticable difference.

I am still gonna get upgraded soon. This thing works, but is not the best. A average file job will beat it.

-Pat

 

[galde]

The older 511 grinders (really Tecomec in a different color) were reversible, but in order to get UL approval, the reverse option was eliminated by replacing the reversing switch with a non-reversing switch. You can restore the reversing capability by replacing the switch with the old style. You really need the reversing capability to grind the chain properly, UL and OSHA notwithstanding.

 

[WOODBUTCHER]

I have a newer 511a, can i reverse it. If so where would a guy get a switch? TYIA

 

[Patrick62]

I think so...

Check if the motor is a permanant magnet style (I bet it is).
As for a switch... Radio shack? Electonic supply house? True Value??
double pole, double throw. Meaning 6 pins on the back. The two in the center are the commons. They toggle between 1 pair and the other pair of end terminals.

Re-read my thread starter, it really is fairly easy. The one little annoyance is that when starting it up in reverse the wheel and hold nut wants to remove itself! Tighten it firmly.

BTW, I just ordered me a NEW 511a, and am looking foreward to actually sharpening something, rather than kinda sorta adding a blunt edge!

-Pat

 

[clyde]

get a MAXX chain grinder. The table is symetrical and you can grind both sides of th chain the same direction. It is much better than a 511. I can get them cheaper also.

 

[Oregon Engineer]

Hey Pat,

Since you are reversing the direction of your chain grinder here are two important suggestions.

1) Get some good goggles or safety glasses and wear them.

2) Do a ring test on all your grinding wheels before using them. With one hand support the wheel by putting a screw driver through the arbor hole. With the other hand lightly tap side of the wheel, near the outside edge of the wheel, with a small metal tool. If the wheel makes a clear and prolonged ringing noise (like a wine glass) then it should not be cracked. If the wheel does not ring clearly or sounds like a cracked dinner plate then pitch it in the garbage can.

I've taken high speed video of a wheel breaking with it in the reverse direction. Then end results will not look very good on your face.

 

[Patrick62]

I ain't no dummy

Those little wheels are spinning at something like 3400 or better in RPM. The biggest issue is that the drive hub was not designed to run in reverse. Tends to want to unscrew itself, mostly at start up.

I know the safety items here.
I never sit directly in line with the wheel (the sparks burn a bit)
Safety glasses (goggles?) excellent idea, but since I am already wearing glasses...

With all the other grinders, chop saws, dremmels, etc. I think I am qualified to handle this.

Dremmel can get to 20,000 rpm
Same for the air powered die grinders.
AC sidewinder can get to 8500 (with real power)
Chop saw is just brutal...

-Pat

 

[Moparmyway]

I have a newer 511a, can i reverse it. If so where would a guy get a switch? TYIA

You need 2 switches. You can keep the origional to energize and de-energize the hot leg. Then use a DPDT switch to switch EITHOR the start winding or the run winding. On mine, the start winding was the red and blue leads from the motor-with the red to the capacitor. The black and green leads are from the run winding. The "start winding" is really the split part of the split pole motor, and not really a "start winding" as it never drops out, but shifts the phase to bring in an additional winding which aids in starting and helps the motor run stronger. Anyway ........ I kept the cap circuit wired in straight and I decided to switch the run winding, so I set the switch up to swap the run wires with the hot and neutral wires. Works like a champ !!

I made a plate for both switches and the wires are tucked away nicely .........

 

[Billxx]

I think so...

Check if the motor is a permanant magnet style (I bet it is).
As for a switch... Radio shack? Electonic supply house? True Value??
double pole, double throw. Meaning 6 pins on the back. The two in the center are the commons. They toggle between 1 pair and the other pair of end terminals.

Re-read my thread starter, it really is fairly easy. The one little annoyance is that when starting it up in reverse the wheel and hold nut wants to remove itself! Tighten it firmly.

BTW, I just ordered me a NEW 511a, and am looking foreward to actually sharpening something, rather than kinda sorta adding a blunt edge!

-Pat

Patrick62, thanks for the outline to install the DPDT switch in the Harbor Freight chainsaw sharpener. It works great, I added a cover over the switch lever so it couldn't be switched while the motor is running and I found a simple and effective fix to prevent the wheel and flange from coming apart when starting in reverse. I added a "Jam Nut" (M14-1.5 x 4.5 mm) to this assembly.

 

[Billxx]

Here is a link to the YouTube video I posted about the "Fix" I installed in the chainsaw sharpener I bought from Harbor Freight...

 

[heimannm]

I believe you must switch the polarity of the start windings to achieve the desired results as the run windings simply spin the motor in whatever direction it is already running. You can achieve reverse action by spinning the motor in the desired direction before you switch the power on, may require the use of a drill or similar tool to get it going fast enough. There is not really an issue with the wheel coming loose with starting in reverse as the motor is not that powerful and it does not really apply that much torque to the screw. I added switches to both of my grinders according to the attached wiring diagram. I wish I could provide proper credit for the drawing but I don't remember who originally posted it, someone from Australia if I remember. The maroon colored switch is the DPDT (double pole, double throw) switch that was added.







Note that I have since changed my grinding wheels to the CBN type available from Bailey's, I like these much better than the pink ones and in my experience they have less inertia that the pink wheels and minimize overheating the chain.

Mark

 

[Billxx]

I believe you must switch the polarity of the start windings to achieve the desired results as the run windings simply spin the motor in whatever direction it is already running. You can achieve reverse action by spinning the motor in the desired direction before you switch the power on, may require the use of a drill or similar tool to get it going fast enough. There is not really an issue with the wheel coming loose with starting in reverse as the motor is not that powerful and it does not really apply that much torque to the screw.

Mark, What you have is a diagram and modification for an AC motor powered machine. The machines here in this thread are DC motor powered machines. Altogether different. Nice pictures and wiring diagram but not relative to this thread at all.

 

[heimannm]

Woodbutcher asked about the 511A and Moparmyway responded, the grinder and discussion there relate to the AC versions as I describe in my post. The DC units are certainly easier to reverse by simply switching the polarity of the power to the motor.

Mark

 

[Billxx]

The DC units are certainly easier to reverse by simply switching the polarity of the power to the motor.

Mark

Mark, You're absolutely right, just as Patrick62 outlined, after cutting the 2 wires going from the power board to the motor and looking at your wiring diagram, the 2 black wires from the switch connect to the 2 wires going to the power board and the red and blue wires from the switch connect to the wires going to the motor, the red & blue wires stay crossed on the switch like in your diagram. (all the other stuff in the wiring diagram is ignored)

Please note, however, the fix I shared in the video on YouTube must be installed prior to this modification on the DC units. (like the one I bought from Harbor Freight)