FREQUENTLY ASKED QUESTIONS ABOUT BANDSAW SHARPENERS AND THEIR ANSWERS

1. "WHY ARE MY CAMS BROKEN?"
2. "WHAT'S WRONG WITH MY FEED FINGER? IT'S MOVING WITH A JERKING, CLUNKING ACTION INSTEAD OF SMOOTHLY AND EVENLY."
3. "WHY IS THE FEED FINGER 'SPRINGING' THE SAW TOOTH AWAY FROM THE FACE PLATE?"
4. "WHY DOES MY GRINDING WHEEL HIT THE TOP EDGE OF THE FACE PLATE?"
5. "WHAT IS THE BEST METHOD FOR INSTALLING NEW CONE SCREWS?"
6. "WHAT DO I NEED TO DO TO GRIND TWO DIFFERENT TOOTH SHAPES ON ONE SHARPENER?"
7. "HOW OLD IS MY BAND SAW SHARPENER?"
8. "I'VE FOUND AN OLD BAND SAW SHARPENER AVAILABLE CHEAP. CAN I REBUILD IT?"
9. "HOW DO I ADJUST MY BACK FEED FINGER FOR THE PROPER STROKE?"

1. "WHY ARE MY CAMS BROKEN?"

Armstrong purposely splits our cams in half for faster, easier installation and removal. Refer to Armstrong Band Saw Sharpener Operating Suggestions for installation and timing details.

2. "WHAT'S WRONG WITH MY FEED FINGER? IT'S MOVING WITH A JERKING, CLUNKING ACTION INSTEAD OF SMOOTHLY AND EVENLY."

Double-check the rotation of your cams. Make sure they are mounted with the arrows going in the right direction. See Check Motors section for proper camshaft rotation.

3. "WHY IS THE FEED FINGER 'SPRINGING' THE SAW TOOTH AWAY FROM THE FACE PLATE?"

Check the faceplate for wear and mis-alignment. The faceplate and the feed finger must be aligned parallel and plumb to each other.

4. "WHY DOES MY GRINDING WHEEL HIT THE TOP EDGE OF THE FACE PLATE?"

The feed finger arm is probably adjusted to the wrong height in relation to the tooth design you are grinding. The gullet of the tooth should be approximately 1/8" above the top edge of the faceplate. The feed finger track, inside the sharpener, determines the height of the feed finger. This track can easily be adjusted to properly position the feed finger elevation.

5.  "WHAT IS THE BEST METHOD FOR INSTALLING NEW CONE SCREWS?"

Replace the nylon bushing (if any) at the same time a new cone screw is installed. Press the bushing into place and grease the cone screw nose to lubricate the bearing surface and threads to prevent rust.

Tighten the cone screw into the bushing to seat it with firm, but not excessive pressure. Back it out one full turn. Re-set the cone screw with just enough pressure until "drag" is felt on the cone screw.  Then tighten the locking jam nut and lock washer to hold in place. When replacing the rocker arm or graduated circle link cone screws, replace one screw at a time.

6. "WHAT DO I NEED TO DO TO GRIND TWO DIFFERENT TOOTH SHAPES ON ONE SHARPENER?"

1. Up to 3 pairs of cams can be mounted on any Armstrong band saw sharpener. Time each feed cam to the corresponding wheel cam and mount the cams for the deepest tooth shape next to the grinding wheel hubs, then the second deepest and finally the cams for the shallowest tooth shape furthest from the hubs.

A shift lever is provided for shifting back and forth between sets of cams.

If the camshaft has not been shifted for several weeks, some binding may be encountered. The procedure for loosening the camshaft is as follows:

a. Clean the camshaft on both sides of the flange bearings with an oily rag. Do NOT use compressed air to clean the shaft.

b. Back out the bearing lock screws in the flange bearings just far enough to be sure that they are not touching the bottom of the keyway. (These screws keep the shaft from turning inside the bearings and they should not be completely removed).

c. Lube both sides of both bearings at the shaft with a light, penetrating oil, such as "3-in-l" or "WD40". Let oil penetrate over night.

d. Lightly tap directly on the camshaft with a plastic, wooden or lead hammer while pulling on the shift lever. Do not strike heavy blows, as this can create more binding. Do NOT exert excessive pressure on the shift lever or strike the shift lever with a hammer.

e. When shifting the camshaft in the future, always wipe down shaft surface around both bearings before attempting to shift. Grit between shaft and inside of bearing can gall the shaft.

2. Align the faceplate. If one of the saws is a double cut, then the grinder should be set up for that saw and the other saw to be sharpened should be no more than 1 gauge thicker or thinner than the double cut saw. If the two saws are very different, a second sharpener may be required.

3. Adjust the feed finger track for the best overall performance of both saws. Again, if the difference is great, then a second sharpener may be required.

4. If a different thickness or shape of grinding wheel is required, use a balancing collar for each.

5. Inspect the sharpener carefully for wear and establish a regular maintenance schedule.

7. "HOW OLD IS MY BAND SAW SHARPENER?"

The serial number of the sharpener will indicate the age of the machine and is usually found over the dust door on the same side of the machine on which the feed finger arm is located. Click here for a list of the approximate dates during which a range of serial numbers were built.

If the serial number tag is missing, the frame style will give a good clue as to the age of the sharpener. Sharpeners made prior to 1953 had frames made completely of cast iron plates bolted together. Frames between 1954 and 1972 had a cast iron front with a steel top, back and sides. Frames since about 1972 were made entirely of fabricated steel.

8. "I'VE FOUND AN OLD BAND SAW SHARPENER AVAILABLE CHEAP. CAN I REBUILD IT?"

Armstrong sharpeners can be rebuilt to perform well. It has been our company policy since 1902 to service what we sell no matter how old it is.

However, it may not be practical to rebuild an older machine. It depends a great deal on what you want to accomplish. If the goal is to use the sharpener for a precision, Cobalt Chromium Alloy tipped saw (or a high production twin or quad), then it may not be practical or cost effective to rebuild a 20-year-old machine for this work.

If the goal is to have an adequate sharpener for occasional use, then it may be a good decision to rebuild even a 30-year-old machine. When making the decision to buy new or rebuild, consider the following:

-How frequently will the sharpener be used? What would be the disruption of other work in the sawmill if the sharpener broke down?

-What would be the cost to rebuild the sharpener? A starting checklist is shown in the Consumable Parts section.

-Are you willing to pay the price to properly maintain a used machine? Older machines use more parts, some of which may be more expensive than the current designs.

9. "HOW DO I ADJUST MY BACK FEED FINGER FOR THE PROPER STROKE?"

There are three types of back feed mechanisms used on Armstrong sharpeners:

1. MECHANICAL
2. AIR DRIVEN WITH POSI-STOP
3. AIR DRIVEN WITHOUT POSI-STOP (Older model)

In all cases, the back feed finger should travel 125% of the actual tooth space.  (For example, the back feed finger on a 1-3/4" tooth space saw travels about 2 3/16".)

1. MECHANICAL

The mechanical back feed transfers power from the feed finger arm shaft to the back feed shaft through two connecting links. Adjusting the placement of the connecting bushing and bolt between these two links will determine the amount of travel of the back feed finger. Moving the connecting bushing and bolt in the slot towards the back feed shaft increases the amount of stroke of the back feed finger.

For No.4 and 6 sharpeners equipped with mechanical back feed, the bellcrank on the feed arm shaft (located near the top of the frame at the back of the sharpener) must be attached at a 45-degree angle.

2. AIR DRIVEN WITH POSI-STOP

The present model No.75 air back feed (ABF) unit with posi-stop is the easiest to adjust and has an adjusting screw to set the feed finger travel. An easily installed upgrade kit (assembly No.8310) is available for older style No.75 ABF units. Set the pressure regulator to where the back feed unit is working smoothly and positively -- about 40 PSI for a 6" wide saw and about 100 PSI for a 16" wide saw.

3. AIR DRIVEN WITHOUT POSI-STOP

The older style No.75 ABF unit without posi-stop has flow control valves on both sides of the air cylinder. Completely open the valve that controls the flow for advancing the saw. The cylinder head must be used as the forward "stop" on this type of ABF. Adjust the other flow control valve until the back feed finger retracts about 125% of the tooth space to pick up the next tooth.