Buying and Maintaining a 20 Year Old Bandsaw

I recently bought my first bandsaw. Like many people, I sourced one second hand after a lot of searching online. I purchased the unit from an old guy who it serviced well for its entire life.

The unit was manufactured in 1996 by Leda in Australia. It is a 14 inch unit with a 'riser' block in increase the height of cut by around 125mm / 5inches. The unit, including some of the casting is very similar to a current 14 inch Powermatic unit. The 2016 Powermatic obviously has several advantages. One glaring advantage of the second hand Leda unit however - it was $200 and has eight blades. The Powermatic unit is listed at over $1600 [Carbatec].

I used the unit for a few weeks and in that time I had the bolt holding the lower wheel on come loose and fall out and found that the unit would randomly not start. If I turned the motor by hand half a rotation it would start fine.

In this Instructable, I will go through everything I have learned and hope to help others buy, maintain, repair and calibrate a small bandsaw.....

It is important to be very specific when looking over a potential purchase. I made the choice to purchase my saw with several small things (and one big thing) that needing fixing. I am comfortable to fix any of this. I also have a good handful of tools to be able to do the work.

UNPLUG POWER LEAD BEFORE CONTINUING

Visual

Overall

Inspect to see if all bolts are present or in other words - look for holes that you think should have bolts. Open all covers and grab, prod and poke anything and everything. If it looks like it should move, see if it does. If it looks like it should be rigid, make sure it is.

Table and Trunions

Take a steel ruler or straight edge with you - with the table fixed in place, sit the edge of the ruler on the top of the table and check for flat. Also, tilt the table up and inspect the Trunions (half-round things the table rotates on - shown in pics). Leda spare parts rep said this style of cast aluminium trunion is notorious for cracking. Replaced both for under $40.

Guides

Look at the blade guides - top and bottom. Bearing should spin freely and without any grinding feeling under your fingers. As you see, the bearing on mine have a lot of damage, one is very stiff and the other one is seized. Also inspect all the cast aluminium around the guides for cracks or signs of fatigue.

Wheels and Rubbers

Check the rubber on the wheels - look for tears and cracks. Turn wheels by hand and inspect thoroughly. My saw has no joins in the rubber and I assume this to be normal practice - a join would cause the blade to skip or bump every rotation.

Electrical

Drive Pulleys and Belts

Check the drive belt tension and alignment. In the pic it shows the belt on mine out of alignment, and loose. If I tightened this up, I expect the belt would skip off and it would overheat plus cause a 'parasitic' load on the motor drawing more current and generating more heat in the motor.

Nameplate

Read the information / name plate and understand it. The current Australian Standard is 230 Volt (V) single phase and 400 V three phase. It is still entirely normal to see 240 V and 415 V respectively. Any 240V single phase machine OVER 10 Amps (A) will need a dedicated power point. This is an important thing to check and understand - it is not uncommon to see a 15A machine with a 10A plug on it. This is a a very bad practice.

Leads

Check the leads thoroughly for any damage or if the outer sheath is pulled out of plugs or boxes like shown in the pictures. If the leads inner colourd wires (cores) are exposed it could mean there is further damage - pulling on a cable too hard can cause damage to terminals and exposed cores is a possible indicator.

Start/Stop

Look for cracks on the buttons or housings. Give the buttons a good press - they should return to their normal spot easily and do not 'grab' when being operated. Don't want a machine that can turn on easily but is a prick to turn off!

Motor

For the motor itself, look for discoloring on the frame or case. I have seen equipment before that turned freely by hand and operated but when run on a circuit with a safety switch, it continually tripped. This was down to a problem inside the motor due to past overheating.

TEST Running

When you want to power the machine up, turn the band saw on and off 10 or more times - give it enough time to fully stop before re-starting. Stupid thing to say but make sure the motor turns the right direction - it should be running the blade downwards where it cuts.

Take any covers off for:

1. Top wheel;
2. Bottom wheel;
3. Both sides of the stand, and;
4. Drive belt

Remove the bolt from the side of the table.

Loosen tension off top wheel and take the saw blade off.

This is a good time to give the saw a good brush and vacuum before we start...

In this step, we'll take the table off and inspect the trunions then clean the rubber rims on the wheels.

1. Remove knobs under trunions.
2. Remove Table.
3. Inspect trunions and mounts for cracks
   This is important especially if your tables trunions are cast aluminium.
4. If the trunions are stuffed contact the manufacturer, importer or re-seller and grab some replacements.
5. Fit them on and hey presto:
   
   While looking at this part of the table, give the fence and 'T' a good inspection. I found a cople of loose screws.

Trunion Problem Fixed.

Grab a couple of old brushes or some sandpaper, hold against the rubber on the wheels and turn the wheels by hand. Just enough to get the sawdust off - not damage the rubber.

Wheels Cleaned.

On my band saw - The trunions were both cracked and caused a dangerous situation. I was rip sawing a 300mm diameter hardwood log about 600 long. When I got almost all the way through, a trunion gave out. The log rolled off, grabbing and snapping the big ripping blade. As the log fell, the blade was ripped out of the saw and tore my shirt quite badly.

When replaced, my table now sits about 12 mm to the right of where it did before. No difference other than the blade does not sit in the center of the big hole in the table. Frankly - this has not detrimental effect in any way on the tables operation. If anything - I now have almost a half inch more cutting width!

Top guides:

Rear Bearing is stuffed but side guide bearings are fine.

With mine I had a small clip to remove then I used an old flat blade screw driver and the rubber mallet to drive the bearing off the rod. Drop the rod through a hole in a piece of timber, sit it in a vice, or over a hole in your bench like I did and gently knock the pin out. Reverse to put the new bearing on the old pin.

Repeat for the bottom bearing...

Note: I found drilling a hole through my timber bench a very good way to sit the bearing flat and knock the pins both out and in. Could have done it by putting two saw horses next to each other or by opening the jaws of a vise and sitting over the gap. If you are going to use a metal hammer, put a piece of soft wood on the surface you are striking with the hammer.

Long story short - there are a lot of videos and and guides on setting and calibrating a band saw.

For me and my band saw it is a simple process.

1. Put blade on loose.- tension to about 75% of 'tight' as per the manufacturers manual
2. Adjust calibration knob and turn top wheel (fairly quickly) by hand.
3. Get the BACK OF THE SAW TEETH to sit on the HIGH POINT / MIDDLE OF THE WHEEL
4. Tension to 100% of manufacturers recommendations
5. Check calibration - make fine adjustment if necessary.

Done.

Note: Whether I am setting up for cutting across or with the grain or re-sawing larger stock to make planks, I set it up the same way and it works for me and my saw.

The saw is 20 years old and has never had any electrical maintenance that I am aware of.

For all the electrical steps, the only real specialist tool I used was a digital multi-meter.

When I got me saw home, I found that it would occasionally not start. This would be maybe 3 in every 10 times I'd try and turn the machine on. To get it to start, I would have to turn either wheel by maybe 1/4 to 1/3 of a turn and it would work fine.

There are a few different types of single phase motors found in bandsaw;.

• Capacitor Run type
• Capacitor Start type
• Capacitor Start Capacitor Run type

It is fairly easy to tell them apart by either the sound or a good visual inspection. For this instructable, I will focus on the Capacitor Start type motor. For me the easiest way to check if I had a cap start motor was to listen when I turned it off. I did this with the drive belt taken off.

1. Turn the motor on and let it get to full speed.
2. Turn motor off and listen carefully.
3. At around 30% speed, (if you have a cap start motor) you should hear a fairly obvious 'click' followed by a constant scraping sound - the scraping sound is normal.

I can not stress this enough: Do not attempt electrical work if you are not suitably qualified and/or capable of performing the task.

Visual inspection: When I removed the start/stop button the space inside had a massive amount of finely powdered sawdust. A good vacuum with the shop-vac fixed this.

1. UNPLUG MACHINE
2. CHECK MACHINE IS UNPLUGGED
3. Loosen cable clamps and pull through some slack
4. Remove start/stop buttons
5. Clean out buttons and vacuum out any dust
6. Make sure earth lug is on securely
7. Refit Start / Stop button
8. Pull back slack cable and tighten up clamps

Seriously - my saw had so bloody much sawdust in the switch. I was blown away.

I can not stress this enough: Do not attempt electrical work if you are not suitably qualified and/or capable of performing the task.

In this step, I cleaned the motor terminals and checked the capacitor.

1. UNPLUG MACHINE
2. CHECK MACHINE IS UNPLUGGED
3. Remove motor from machine
4. Open and clean terminal box
5. Remove capacitor
6. CHECK CAPACITOR IS ZERO VOLTS WITH METER SET TO READ DC VOLTS
7. Remove one wire off the capacitor
8. Check for a reading
   1. The capacitor might need several seconds before it will show up a reading on the multi-meter - especially if you're using a cheap meter.

If your saw is failing to start - there is a good chance the capacitor is blown. If the cap is dead, make sure not to get any of the oily residue on your fingers if you need to change it.

I can not stress this enough: Do not attempt electrical work if you are not suitably qualified and/or capable of performing the task.

In this step, I realign the pulley and clean the contacts on the centrifugal switch - This DOES require an understanding and respect of electricity and it's consequences.

First thing - a centrifugal switch is inside the motor. The purpose of the switch is to be closed when the motor is starting and to be open when the motor is at speed. It generally opens up somewhere around 30% of rated speed (after what is sometimes called 'pull up torque' is reached).

This kind of motor has good string starting torque. The windings in the motor for starting are 'removed' during full speed operation by opening a switch, the windings don't have to handle current all the time. As a result, the windings can be driven a lot harder than they could hand at 100% duty cycle. Down side - the switch is mechanical so it has bits that wear out and bits that need servicing. If you do not set the centrifugal weights right at the end and the switch does not open, it will burn out the windings or burn out the capacitor.

These contacts were the cause of my machine randomly not starting. A buildup of carbon on the contacts meant that the start capacitor was not always operating.

1. UNPLUG MACHINE
2. CHECK MACHINE IS UNPLUGGED
3. Setting the Pulley
   1. Remove fan cover from motor
   2. Remove fan from motor
   3. Lightly thump the pulley on to set it properly
      1. Make sure to use a rubber mallet or use an extra bit of wood if you are using a steel mallet.
      2. Use a bit of wood with a hole in it to 'pad' the pulley Loosen grub screw from pulley Stand motor on fan end (on a bit of old wood)
4. Cleaning the Centrifugal Switch contacts
   1. Remove centrifugal weights from motor shaft
      1. Make a good note of how far on the shaft these are so you put them back later in the right spot - very important!!
   2. Get access to Centrifugal switch contact
      1. Using 400 (or higher) grit sandpaper, give the contacts a light clean.
      2. Use a fine brush to clean out any carbon buildup.
   3. Re mount the switch assembly.
   4. Re mount the centrifugal weights
      1. Note: When tight and in place, make sure to operate by hand and watch the contacts open and close. This can also be checked using your multi-meter.
   5. Put the fan back on
   6. Put the fan cover back on
5. Reassembling
   1. Mount the motor back in the saw
   2. Align, tension and tighten the motor and belt in place.
   3. Turn by hand and inspect closely.
   4. Turn by the start / stop switch and see how it goes.

My process: This whole bit took me about 45 mins. The capacitor had around 60V DC in it - I short out the capacitors terminals using my pliers. It did make a small spark - expect it if you do this.. Checked the voltage again and it was zero so good to go. The vibration and noise produced by the band saw was considerably less after all this.

After doing everything else I tried to tackle another, substantially annoying problem. The saw guide is not square with the saw blade. Specifically I mean the lifting rod the guides are mounted on is the problem. When the guides are lifted or lowered, they also go left or right. If I rise the guides they also go right, if I lower the guides they also go left. The problem was big enough that if I moved the guides maybe 150mm, the blade would be pushed enough that it would rub on the guides under the table.

My saw has no sideways movement in either top or bottom saw wheels and the guide rod goes through a machined / drilled hole in the cast iron so it has no calibration either. Inspection of the riser block shows that the top and bottom have locator pins that does not allow for any movement there either.

After several drinks, a few crap drawings and catching some Pokemon with my daughter, I decided to go to my local machinery shop and see them. They were no help at they could not understand what I meant - even when I pointed it out on a very similarly constructed new 2016 band saw (demo floor stock).

After some experimentation using old hack saw blades as shims, I figured that proper shimming of the riser block would be my best (non-destructive) solution.

So I picked up a pack of Assorted Shim Steel Sheets and got into it.

• Process to Alight Guide to Saw Blade.
  1. Loosen off the saw blade.
  2. Loosen the bolt that holds the top cast iron arm to the bottom of the saw.
     In my case, this is also where the riser block is located.
  3. I cut and insert 1 x 0.25mm length of shim steel at BOTH the top and bottom of the riser block.
  4. Tighten up the big bolt, tighten up the saw blade.
  5. Check the guides for parallel movement to the saw blade.
  6. Repeat until you are satisfied.
     I had to do this about 8 or 9 times to get it right. Ended up with a total of 1.75 mm of shim steel.
  7. This all in all took me roughly 1.5 hours to get it right.

Standing back it does look very slightly different to normal - I had to re-adjust the Zero Degree stop bolt and the saw guides under the table when I was done. The shimming has caused the throat of the saw to open up a tiny bit and the blade is now about 4mm to the left of center in the table.

I would much rather have to re calibrate the table and the lower guides once than the adjust the saw guides every time I raise or loser the blade guides 100mm.

I cant really show it in the photos but I now have less than the thickness of a sawblade difference from top to bottom. I could remove this if I wanted and probably will in the coming weeks but in the process of this fix, I put a piece of shim steel through pluggers (flip flops) and into my foot. Shim steel is proper sharp after it is cut with old tin snips.

There are a heap of videos, guides, tutorials and probably a couple of instructables for setting the saw blade but none I can find for getting the guide to be plumb with the blade - I hope this helps someone...

Last thing I did was go round with some 2 part epoxy and bits of rubber. Put some packing around a few bits and removed a lot of the vibration and noise from the saw.

After what was realistically six hours of work and fluffing around, I am totally happy with my saw. It cuts well, is not noisy, does not vibrate and I know it well. It is now grounded, the belt is better than finger tight and the pulleys are straight. It starts every time and the switches aren't full of powdered sawdust.

I hope this can help someone else out.