511A Grinder - Improvements / Tweaks?

[Philbert]

I read some of the threads on tweaking the Northern Tool grinders, and thought that we ought to have one for the venerable Oregon 511A (and related Italian grinders). This model does not have the same quality issues as the knock-offs, and I know that it has been replaced by the 511AX, but there still have to be a few million (?) of these things in use.

Please add things you have done, or issues that need to be resolved.

Castings
When I received mine new, the vise casting did not rotate as smoothly as it should. I polished the rough spots on it and the base with fine emory paper and a ScotchBrite wheel. I don't use any grease because the the grit and dust would stick to it.

Angle Scales
There are 2 head-tilt angle scales on the grinder. They did not agree. I removed the scale on the top and elongated the holes with a Dremel tool so that I could shift it over a bit, and remounted it with the screws and double-stick tape. The scales still do not agree over the entire range of movement, but they do at 60 degrees, where I use it the most.

I checked the vise rotation scale, after centering the vise per the instructions, with a factory ground, new out of the box chain, and it seemed to line up at +/- 30 degrees - again the settings I am most likely to use, so I assume that it would be consistent with other settings as well.

Mounting
My grinder is not permanently mounted - it is bolted to a board so that I can clamp it to a table when needed, then put away. I like to grind outdoors when I can to keep the grit and sparks out of my basement.

Grit
I clean the grit off after each grinding session with a brush or compressed air. But some grit 'sticks' the the front of the upper casting. I covered this area with aluminum tape, which can be removed and replaced if this build up gets to be a problem. For some reason, the grit does not stick as tenaciously to the aluminum tape.

Head Travel
Someone noted that the grinding head on their NT grinder travels a large distance to reach the cutters, so he 'de-tuned' his spring to keep it from rising up so much. I did not want to do that. So I threaded a piece of heavy boot lace through the existing holes (for the accessory foot pedal) to limit head travel, but the spring is so strong that it pulled the cord right through the spring-loaded cord lock I used.

After trying a few things, I used a larger cord lock, one that allows me to pass the cord though a second time, and this works. It is infinitely adjustable, allows me to fully raise the head for any reason, and did not require any permanent modifications to the grinder. It definitely saves time when grinding.



Philbert

 

[Eccentric]

opcorn:opcorn:opcorn:

 

[Nato]

oregon grinder

this is what i did to mine. i built my work table xtra tall (i'm 6'3") so when the grinder "sub frame" clamps in the vice, the grinder chain rails are about 8 inches below my eye sight line (when i'm standing). this makes it very comfortable, and quick to get setup to grind a chain. i welded 1/2 inch round stock to either side of the "sub frame" to hang my chains. left side for the chains that need ground,and right side for finished chains. i used to screw my grinder to my saw horse, but i grew tired of that. it was flimsy at best. this thing is rock solid now and portable. it makes grinding quick and easy.... in my book that =fun. my next improvement to the grinder is going to be a better placed ,brighter light so i can see what i'm doing,or maybe just glasses?

 

[galde]

I have an old Tecomec with reversing motor. I wouldn't have one without reversing capability.
Some of my tweaks:
1) I taped tygon fuel line lengths to the top casting to hold the allen wrenches for the shield and grinding wheel so they are always handy.
2) The head tilt is always either at true vertical or at 30 deg from vertical so I clamped stops at these angles so I don't have to strain my neck to read the scale on the back side every time.
3) By calibrating the depth adjustment (my grinding wheel moves 0.005" for each groove on the knob) and attaching a pointer on the lower friction-adjusting knob, I can uniformly grind all of the depth gauges to within a couple thousandths of the desired depth. I locate zero by running the adjusting knob upward to permit the wheel (stopped, of course) to rest on the top edge of the reference tooth (after sharpening ) and then run the adjuster down until the wheel just picks up and clears the tooth while applying the same downward pressure applied when finishing the actual grind.
4) I attached a flexible gooseneck lamp with a 100-watt brightness CF bulb for illumination. The built in lamp in the newer models is worthless since it is on only while the motor is on.
5) After wearing nearly through the vise rail with the cam clamp, I added a replacable wear plate held in place by the Allen head bolts holding the vise together.
6) To avoid having to readjust the tooth pawl when changing tooth sides, I use a short length of 1/4" fuel hose with a slit in the side to move the pawl back and forth. The slit hose is alternately pushing the pawl rearward or parked on the open side of the pawl bolt.
7) When grinding I use a tool to further stabilize the tooth against moving. The chain vise grips the drive links only, and with well-worn chains there can be wiggle room for the tooth. The tool is like an awl with a slight curl at the tip. I use it to bottom the drive links firmly while clamping, and I hold the tool tip firmly on the tooth while grinding.
8) I made a radial reference mark on the arbor where the wheels mount. I made radial reference marks on all the wheels, with matching marks on both sides of each wheel. When I mount a wheel, I align the marks pointing upward while pulling downward on the wheel while tightening the clamping bolt. This reduces the vibration caused by variations in wheel balance and slop in the arbor hole. If a wheel is smooth running when removed, it can be remounted and it will still run smooth.
8) I have experimented with forced air cooling, but I still don't have the right flexible nozzle rigged up.
9) The wheels I use are vitrified (mole-mab), Stihl diamond, and CBN. Each type has its fit.
10) The grinder is mounted on a length of lumber that can be clamped anywhere as needed.

 

[Philbert]

I have an old Tecomec with reversing motor. I wouldn't have one without reversing capability.
Some of my tweaks

Great ideas. Love to see some photos!

A few years back someone posted instructions for making the motor reversible - anybody got it?

Somebody suggested that if they increased the range of motion for the head tilt and vise, you could grind both Left and Right cutters the 'right way' without a reversing motor, and the guarding problems associated with that.

Philbert

 

[galde]

The reversibility feature was killed to secure U.L. listing since the U.L. "experts" deemed it unsafe for the grinder to throw sparks toward the operator. Some of the resulting grinders still had reversible motors but the new switches (double pole-single throw?) would not permit reversible wiring. The old reversing switches (double pole-double throw?)could still be used to make the units reversible. I don't know if the current models can be made reversible with the right switch.

 

[Philbert]

The reversibility feature was killed to secure U.L. listing since the U.L. "experts" deemed it unsafe for the grinder to throw sparks toward the operator.

OSHA too. It's not just the sparks, it's for those rare, but real, occasions when the wheels explode.

Philbert

 

[galde]

The wheel explosion likelihood was increased when the motors were no longer reversible. The unwary operator who fails to solidly grip the tooth is likely to burst the wheel after changing from the left teeth to the right teeth. Any play in the right-hand tooth lets the tooth lean into the wheel with violent results.

 

[J.Walker]

Install thin washers between the vice half's to grip the chain better.

Check the run-out of the arbor. Mine was so far out it caused the grinding wheel woble.

 

[Philbert]

Check the run-out of the arbor. Mine was so far out it caused the grinding wheel woble.

Were you able to fix/compensate for this, or were you able to return it to OREGON as defective?

Philbert

 

[J.Walker]

I took the motor with the arbor on it to a machine shop and they trued it up.
Now my cutters have a mirror finish after grinding.

 

[Granite Stater]

Now my cutters have a mirror finish after grinding.

What type of wheel are you using?

 

[J.Walker]

What type of wheel are you using?

It's just a pink Oregon wheel.
Dressing the wheel is a very inportain for a smooth finish.

 

[Philbert]

Dressing the wheel is a very inportain for a smooth finish.

Made in Italy - I hope you are using Italian dressing!

Philbert

 

[Dan_IN_MN]

I took the motor with the arbor on it to a machine shop and they trued it up.
Now my cutters have a mirror finish after grinding.

Was it bent or machined out of true?

 

[J.Walker]

Machined the arbor is just pressed onto the shaft.

 

[J.Walker]

Here is the grinder mounted on a board that is bolted to the workbench.
There is a swing arm lamp attached to the back of the board. More light the better for grinding.
The shock cord is attached to a nail at the bottom of the board.

.

 

[J.Walker]

In the stock form you can see how high the grinder head is. The shock cord really helps.

.

 

[Philbert]

In the stock form you can see how high the grinder head is. The shock cord really helps.

The manufacturer actually sells a foot pedal option for the grinder. There is a cable that runs up through the hole in the base, and through the holes that I used to thread the boot lace. It seemed like an interesting idea, and could speed things up, but I don't think that I could get the same feel and finesse that I can by hand. Might try it sometime with cord, just to see.

Anyone try the foot pedal?

The self-clamping (hydraulic) vise also seems like a good idea. Some A.S. members seem to really like it. Others said that they had leaks and trouble getting parts. This might be something that a handy guy could rig up using a foot pedal and some hydraulic mountain bike brake parts, or maybe a small pneumatic cylinder?

Philbert

 

[Philbert]

Hey Oregon (if you are listening)

Here is an improvement I would like them to make: replace the large knobs with 'T'-handles. I have small hands and sometimes find them hard to grip, loosen, and tighten.

I can try and find some that are the right thread for my grinder, but it would be nice if they came that way - would be easier to use and would not cost them any more.

Philbert