Saturday, January 9, 2016

Converting a Wood Cutting Band Saw into a Lapidary/Diamond Band Saw

Converting a SKIL Model #3386-01 9" Band Saw into a wet cutting lapidary band saw for cutting rocks and glass.

The saw in operation

WARNING! - I don't recommend anyone attempt this unless they are willing to assume the risk of electrical shock, because your working with electrical equipment and water in close proximity to each other.  Take all necessary precautions to avoid electrical shock.  Use a ground fault circuit interrupter (GFCI) when operating this equipment.

Equipment and Parts:

I choose a reconditioned SKIL Model 3386-01 Band Saw for several reasons.  Corrosion was of primary concern, and the body of this saw is constructed almost entirely with plastic and aluminum. However, all the bolts, nuts and screws are steel. The saw blade wheels are manufactured with aluminum, but the bearings appeared to be double-sealed, which means they are not water proof, but are resistant to dust.
  1. SKLR3386-01-RT  Reconditioned SKIL 9" Band Saw with Light $89.99
  2. 301395925194 KENT 59.4"x1/4", Band Saw Blade Diamond Coated $102.00 Each
  3. 90131A553 Abrasion-Resistant Cushioning Washer, SBR Rubber, 1/2" Screw Size, 0.500" ID, 2.250" OD (Packs of 10) $7.55
  4. 10095K51 Loc-Line Any-Which-Way Coolant Hose 1/4" ID, Coolant Supply Valve, 1/4" NPT Male (Packs of 2) $10.98
  5. 10095K42 1' Length of 1/4" ID Loc-Line Any-Which-Way Coolant Hose $6.59 per pack of 1
  6. 10095K17 1/16" Diameter Round Nozzle for 1/4" ID Loc-Line Any-Which-Way Coolant Hose $4.35 per pack of 4
  7. 10095K62 Bracket Mount Manifold for 1/4" ID Loc-Line Any-Which-Way Coolant Hose $14.67 Each
  8. E982DFN-CTN CARLON 1/2-in Schedule 40 PVC Transition Type FSS - Single Gang Box $5.58 Each
  9. PTC100GY Hubbell TayMac 1-Gang Rectangle Plastic Weatherproof Electrical Box Cover $4.27 Each
  10. 15-Amp Switch $4.90 Each
  11. 871980305016 GeoGlobal Fountain Pump 70-130 GPH $21.98
  12. CB50040BL Olson Cool Blocks 1/4" $17
First of all, the electrical switch located on the front of the machine needed to be modified.  I removed the switch, and found a small printed circuit board (PCB) attached to the back for powering the LED light. The circuit board was well insulated with a large shrink tube surrounded the entire PCB.  The PCB was hot glued to the inside of the vacant space.  A Schedule 40 PVC Single Gang Box was mounted on the back, and the wires were rearranged and connected to the switch in this box. This is covered with a Plastic Weatherproof Electrical Box Cover, and the power cord and cord to the motor are routed through compression sealed fittings at the bottom of the gang box.

Previous location of Main Power switch, and covered with a piece of plastic 
sealed with silicon.  Seal wire for LED light with silicon.

Weather proof single gang box and switch located
on back of saw.

Back of Band Saw.  Note: I haven't fabricated a cover for the motor yet.
All of the bolts, screws and nuts were removed and coated with grease to prevent corrosion.  Unfortunately, I didn't have any Anti-Seize or similar product for this purpose.

The saw was plumbed to provide water/cutting fluid to the diamond blade.  All of the plastic parts for the coolant hose were purchased from McMaster-Carr, and the part numbers are shown above.  The brass parts and hoses were purchased locally at Sears.

The water/cutting fluid system is powered by a fountain pump.  I purchased a 70-130 GPH pump for this purpose, which may be more than enough flow for the saw.  However, the flow from the pump is adjustable, and the next smallest size was not much cheaper than the model I purchased.

When using the saw we place it on a 16"x10"x5.5" base constructed of 3/4" PVC siding.

This base sits in a 40qt. - 16.8"Wx24.14"Dx7.8"H plastic container as seen below.

SKIL Model 3386-01 converted wet band saw with a diamond coated blade.
The fountain pump is placed in the bottom of the container, and covered
with water or cutting fluid.  The saw and pump are plugged into a
ground fault circuit interrupter (GFCI), similar to the one pictured in
the lower right of photo.
Additionally, I added Olson Cool Blocks for upper and lower blade guides.  I was reluctant to use the metal guides that came with the machine with the diamond blade.  One problem with the Cool Blocks is they are a bit smaller in diameter than the metal guides, but they seemed to work fine.

One other modification I made was the addition of a Sling Washer between the small drive pulley and the motor bearing.  I used an Abrasion-Resistant Cushioning Washer, SBR Rubber, 1/2" Screw Size, 0.500" ID, 2.250" OD as seen below.  Sling Washers are common items on water pump shafts to prevent water from creeping up the shaft and into the motor bearings.

Sling Washer

NOTE: I have not constructed a cover for the top of motor yet, and temporarily cover the motor with a piece of plastic.  Some sort of cover MUST be added to prevent water dripping into the motor housing.


After completing the conversion, I was extremely disappointed with the blade tracking of the SKIL Model 3386-01 Band Saw.  The upper wheel mount and the adjustment mechanism for this saw was poorly designed, cheap and resulted in a great deal of play and difficulties with tracking.  I found the upper and lower wheels were not parallel, and required shimming of the upper wheel mount.  The lower wheel has no adjustments.  This requires all adjustments for alignment to be made by the upper wheel mount.

After tuning the machine, we were able to cut 2"-3" thick slabs fairly easily, and the motor never slowed.  We also cut a wine bottle in half very easily.  Overall, the saw worked as I had hoped, and my only complaint is the blade tracking mechanism.

Is this a less expensive alternative to buying  a lapidary/diamond band saw...maybe.  There are small inexpensive wood cutting band saws on the market that might be better candidates for conversion than this make and model.

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