The 4×6 Bandsaw
Once you get a mini-lathe, you will find that you have a never-ending need to cut workable lengths of round stock from the 3 to 6 foot lengths that it usually comes in. You can buy shorter lengths from sources such as Metal Mart, but most suppliers charge extra for this service.
A hacksaw will do the job if you have time, patience and a strong arm, but a bandsaw is like having a tireless apprentice ready to cut whatever you need while you continue to work on the important stuff.
This is because most horizontal or horizontal/vertical bandsaws such as the one described here, clamp the work in a vise built into the saw and automatically shut off when the cut is completed. This leaves you free to work on other things around the shop while the bandsaw hums away in the background.
If I could have only one other power tool besides my mini-lathe, it would be a bandsaw. If you’re on a tight budget, you should consider getting one even before the inevitable day when you find that you can no longer go through life without a mini-mill (for most of us, this day occurs less than a month after getting a mini-lathe!)
The ‘standard’ bandsaw for mini-lathe owners is widely known as ‘the 4×6 bandsaw’ since it can cut through a rectangular cross section up to 4×6 in size (try that with a hacksaw!)
It can also operate in an upright position, but is very limited in this mode due to the short throat depth (distance from the blade to the support casting). Even so, after adapting mine for a decent table, I find it quite useful in the vertical mode.
Bandsaw Meltdown – Fire Hazard!
Moral of this story: do not leave the bandsaw unattended while it is in operation!
My 4×6 bandsaw has become an indispensable part of my shop. Any day that I work in the shop for more than an hour, chances are that I will use the bandsaw. Mine has been in use now for about two years and has been a faithful, if somewhat cantankerous, companion.
A nice feature of the saw is the automatic cutoff. You can place a piece of work in the vise and let the saw do its work while you attend to other business around the shop.
Its not unusual for a fairly large piece of stock, say 2 inches square, to take 4-5 minutes to cut through. Thus it was that the saw was working away today while I was setting up the lathe for another operation.
Around noon, I was at a good stopping point and decided to take a lunch break. Glancing at the saw, I observed that it was nearly finished cutting through a 1×1 1/2″ rectangular piece of aluminum stock. My shop is in the garage, separated from the kitchen by a door.
I generally take only about 15 minutes for lunch and I can hear the saw from the kitchen, so I did not think twice about leaving the saw to complete its work. As it turned out, lunch went a little longer than usual as I turned on the TV and got interested in a show that was on.
I returned to the shop after about 30 minutes and, opening the door, was quite surprised to be met by a cloud of acrid smoke! Quickly I looked around, trying to determine the source of the smoke.
My first reaction was to shut off the power strip that provides power to the lathe and mill. Then I remembered the bandsaw! Smoke was rising out of the motor vents. I yanked the power cord from the outlet and threw open the main garage door and the back door to dispel the smoke.
The saw had stalled in the workpiece within about 1/16″ of completing the cut. With no thermal cutoff built into the motor, it just sat there drawing current and getting hotter and hotter. It is quite possible that a fire would have started, but by luck, a window air conditioner was plugged into the same outlet.
It appears that when the compressor of the air conditioner kicked in, it tripped the circuit breaker for that circuit, cutting off power to the bandsaw. This must have happened only a minute or two before I returned to the shop, as smoke was still rising from the bandsaw motor when I returned.
Some time ago, I had modified the saw by making a plywood backing support for the pulley cover. The plywood was badly scorched and part of the plastic pulley cover was melted. After 30 minutes of cooling off, the motor was still way too hot to touch.
Then I noticed a stream of melted plastic had congealed underneath the motor. Not a good sign! Further investigation and a complete tear down of the motor made it evident that the motor would never run again.
I also discovered that the lower mounting bolt, that acts as a pivot point for the motor, was missing. The pulley on the motor was therefore canted relative to the other pulley and this may have added excess drag to the motor and contributed to the stall.
The photo below shows the bandsaw motor and plywood pulley cover backing. Although its not evident from the photo, smoke was still coming out of the motor housing when this photo was taken.
If you look carefully, you can see that the plywood is scorched near the motor. Near the bottom of the motor you can see some grayish melted plastic dripping from the motor housing.
The next photos shows the melted area of the plastic pulley cover and inside of the motor after disassembly.
The top photo is a shot of the piece of aluminum that was being cut; the lower photo is the scorched plywood pulley cover backing.
Bandsaw Meltdown: The Sequel
It quickly became apparent that the original bandsaw motor was not salvageable, so I began a search for a replacement. From trips on my mountain bike around an area within a few miles of my home, I was aware of some places that people sometimes illegally dumped old appliances.
With luck, I might find an abandoned washer or dryer from which I could procure a workable motor. A quick check of these locations turned up three kitchen ranges, but no washers or dryers.
My next effort was to attempt to revitalize a 3/4HP motor from an old swimming pool pump that I had removed from service about 10 years ago. Since then it has been sitting in the woods behind my house, just in case I ever needed it.
When I took it out of service it was still working, but apparently had a bad bearing and had become very noisy. I brought it into the shop and cleaned out the inevitable ants and spiders and then plugged ‘er in. It worked, but was obviously way too noisy to be useable in the shop, so the next effort was devoted to determining how to replace the bearings.
I spent a few hours on this problem without making a whole lot of progress. At first I couldn’t figure out how to remove the impeller, but the guys on the 7×10 group promptly helped me solve that problem.
Once the impeller was off, I had to remove the centrifugal switch from the back of the motor. Since everything was rusted in place, this apparently simple operation consumed another 2-3 hours. By the end of the day I still had not been able to remove the front bearing.
Since I use my bandsaw just about every day I’m in the shop, I decided to bite the bullet and just order a new motor, rather than futz around trying to repair the pump motor or find a junk-yard replacement. My daytime schedule is pretty tight, and I knew it would be at least a week before I would even have a chance to get to a junk yard.
Ordering a new motor turned out to be a quick solution as I placed my order on the Grizzly web site early Monday morning and the motor was waiting on the porch when I got home from work on Wednesday.
There was a dent in the start capacitor cover (visible in the photo above), but otherwise the motor was in perfect condition. The original motor was purported to be 1HP, but I knew better than to believe that. I figured it would be nice to have a little extra power, though, and since the replacement motor was also an import, I assumed that it, too, would be overrated.
The motor I ordered was a 3/4HP, P/N G2903 for $99.95 as of 12/31/08. $79.95 plus about $10 shipping. It is somewhat bigger and heavier than the original motor and I suspect is actually more powerful.
Without hesitation, it cut through several pieces of the same stock that had stalled the original motor and was not even warm to the touch when done. One minor annoyance is that the mass of the motor rotor causes the motor to jump when power is first applied.
It seems a tad large for the bandsaw, and changed the balance of the arm assembly. I backed off the tension on the counterbalance spring to compensate for the extra weight of the motor.
I’m pretty certain that a 1/2 HP version of the same motor would be about equal in power to the original motor and would certainly run cooler. Reading through an issue of HSM, I ran across a picture of a similar bandsaw that looks like it has an Enco logo on it.
The motor was similar in size to my replacement motor. I don’t know if it was the original motor on that bandsaw or not.
For years after replacing the motor (ten, in fact), I ran the bandsaw without a guard over the belts and pulleys. I never felt right about that, because I take safety seriously, but making a belt cover is not as simple as it might seem, due to the odd angles and shapes involved, so I kept putting it off.
Recently I noticed some black rubber shavings on the floor of the shop. Investigating, I discovered that the pulley of the bandsaw had been rubbing against the power cord for the bench grinder, which sits next to it. Hmmm…, I said to myself, I guess I need to do something about this. So I did.
As with most prototyping projects, I just jumped in. I knew it probably would take me more than one attempt to get it right. There were two convenient bolt holes in the arm casting, left from the original belt cover, so I took advantage of those.
After cutting a rough prototype base from 1/4″ MDF, I had a pretty good idea of what I needed to do. I cut a second base and then closed it in using pieces of 1/4″ MDF cut to shape on the radial arm saw.
Once cut, I glued them with wood glue, then drove some small diameter (5/8″ x 23 gage) nails with an air nailer to hold things together until the glue set and to add some extra strength.
It worked out pretty well, except that when I decided to close in the end, I neglected to include an access hole for the mounting bolt. After much cursing and work with the saber saw and a file, I had an acceptable hole.
The box is open at the upper end so that it can slide off. The pulley and belt are deep enough within the box that they’re pretty well protected. It would be an easy upgrade to cut another piece of MDF to fit the end and screw it in place. Maybe tomorrow…
Bi-Metal Replacement Blade
The stock blade that comes with the bandsaw is barely adequate. I recommend purchasing one or two bi-metal replacement blades when you buy your bandsaw as they are a big improvement over the original.
I don’t know what the component metals are, or why it is better, but it sure cuts faster and lasts longer. I have bought them from Grizzly and Enco for around $16-18. They will last a year or more cutting brass, aluminum and steel.
Here are the results of some tests I ran to compare the cutting speed of the stock blade with the bi-metal blade. The stock blade was fairly new and was used only on aluminum and brass, so should be in pretty good condition.
All tests run at highest of 3 speeds, with minimal spring tension (max weight on the blade) I had to increase tension to keep blade from stalling in 1/2″ alum plate.
|Material||Stock Blade||Bi-Metal Blade|
|1/2″ alum. plate, 5″ cut||5 min||1 min 20 sec|
|2 1/2″ alum. round||10 min||4 min|
The bi-metal blades that I’ve been using are Enco P/N 240-4930. They work fine on aluminum steel and brass and any other material that I’ve needed to cut. Each blade has given me years of service, usually ending when I inadvertently attempt to cut hardened steel and dull the teeth.
Here’s a picture that shows several of the mods:
- Plywood & 2×3 wooden stand
- Quick-change table for vertical use
- L-shaped extension for cutting plate stock
I had a lot of trouble in the early days with the blade becoming derailed. This was solved, for the most part, by keeping the blade tightly tensioned – about as tight as you can get it.
When you order your saw, order a bi-metal replacement blade with it. The bi-metal blades are vastly superior to the stock blade and will reduce your cutting times in half and will last several times as long.
The stand that comes with the bandsaw is made from thin stamped sheet metal and is barely adequate to hold the saw up. Within a week or two after getting my bandsaw, I trashed the metal base and made my own from some 2x3s and plywood.
This base is quite sturdy, inexpensive and easy to make. The only tricky part is cutting compound angles on the tops of the 2x3s so that they fit into the corners of the bandsaw casting.
I had to relocate the cut-off switch slightly to make room for the 2×3. Although not shown in the picture above, the sides of the stand have proven to be a handy place for hanging various accessories for the saw, such as spare blades.
Quick-change Table for Vertical Use
The cheap metal table about 10″ square that comes with the bandsaw is just about useless. It also is a pain to set up and take down since you have to remove 2 screws from the blade guide, then insert 2 screws to lock down the table.
I made a replacement table – several, actually, of different sizes and designs – from medium density fiber board (MDF) 1/2 or 5/8″ thick.
You can get this material at Home Depot very inexpensively and it is smooth and easy to work with. It does tend to absorb oil and dirt, so I spray paint it to seal the surface and give a nicer working surface.
My replacement table can be set up or removed in under a minute since only a single 1/4-20 socket head cap screw locks it in place.
An aluminum plate bolted to the underside of the table has alignment holes that engage with pins on a machined aluminum mounting block that is permanently bolted to the saw frame. This arrangement ensures that the table is precisely aligned and rigid, while only needing one bolt to lock it down.
Here is the mounting block, showing the alignment pins and locking bolt.
The bottom of the mounting block is milled at a 4 degree angle to offset the slope of the bandsaw casting. Two 1/4×20 hex-head bolts engage with holes drilled and tapped in the casting.
If you don’t have a mill, you might be able to cut the base by sawing it in the bandsaw with a wedge underneath to set the angle of the cut and then finish the piece by sanding on wet-dry paper (in ‘wet’ mode).
L-Shaped Table Extension
Frequently I find that I need to cut a small section from the end of a piece of aluminum plate. The stock vise does not lend itself well to this operation so I added an extension table to the base casting of the saw.
The vertical part of the extension helps support tall workpieces. Usually I use a C-clamp to clamp the workpiece to the vertical extension.
Here’s an example of cutting a long piece of 1/2″ aluminum plate. I had to flip it over to finish this cut since the depth of cut is limited by the arm of the bandsaw hanging up on the workpiece.
The vertical part of the extension helps support tall workpieces. Usually I use a C-clamp to clamp the workpiece to the vertical extension. Here’s an example of cutting a long piece of 1/2″ aluminum plate.
I had to flip it over to finish this cut since the depth of cut is limited by the arm of the bandsaw hanging up on the workpiece.
The small screw at bottom center is a fine adjustment for the angle, so that I can set the table exactly on plane with the surface of the casting.
The mounting holes for the vertical extension are oversize so that I can set it exactly in line with the fixed jaw of the vise. The hex bolts pass through these mounting holes into tapped holes in the bottom edge of the vertical extension.
Pulley & Belt Cover
One problem that several owners have reported is the pulley/belt cover rubbing against the pulleys. I spent a lot of time fooling around with this before I finally got radical and solved the problem by cutting away the stock base and making a new one from an old piece of 1/4″ plywood that was lying around.
This allowed me to custom fit the cover and has completely solved the problem. I arrived at the dimensions by the ‘cut and try’ method. I don’t change the belt speeds very often or I would have used a thumbscrew of some sort to lock the cover.
Holding Short or Odd-Shaped Stock
Jerry Fear posted some nice mods to the 7×10 group. The first one shows a small drill press vise mounted on a base plate that is clamped between the jaws of the bandsaw vise.
Small stock, such as the bolt in the picture, can then easily be held for cutting.
This next mod, shows how Jerry replaced the short movable jaw with a second instance of the longer fixed jaw.
He has drilled and tapped it for a jack screw that holds the far end of the jaw in place when clamping stock that is too large for the little vise shown above, but still too short to seat properly between the bandsaw vise jaws. The picture on the right shows a disk shaped workpiece being held down by milling clamps.
Jerry drilled and tapped some holes for the clamp screws into the base of the bandsaw.