Harbor Freight 4×6 bandsaw

This is an update from the post I made back in June 2009.

I still love this saw, but it is certainly not industrial-grade. Here are some tips for anyone who owns or is looking to buy a Harbor Freight 4×6 bandsaw…

First, don’t pay more than about $160 for it. I’ve seen this go on sale several times since my purchase. Besides, after the necessary maintenance you need to perform (below), you’ll spend an extra $50 easily.

Once you do buy it, CHANGE THE GEAR OIL! Take the 6 nuts off the gearbox cover and suck out the nasty oil and gunk with a turkey baster. Then wash the whole inside with kerosene (lamp oil from the hardware store). This saw is cheaply made in every way possible, including leaving the gearbox un-cleaned after casting. The iron is cast in sand, and the sand tends to clump and stay in the corners. The chinese just paint over it, but that doesn’t do anything. You’ll be surprised to see how much sand and nastiness is in there. Also, I’m pretty sure they put used motor oil in there to lube it. See this review if you don’t believe me.

When cleaning, I found brushes didn’t work well and the bristles fell off adding something else for me to get out of there. Don’t bother removing the gears, you’ll need a gear puller to take the drive wheel off, and it’s just not necessary. It’ll take some time, but use your fingers and a stick or something similar (I used a bamboo skewer because it was handy) to scrape and knock all the sand out of the corners. Poke every inch of the inside, you’ll find pockets of sand. Flush the entire box with kerosene. I used this squirt bottle. I propped the saw up so motor end was higher, flushed from the upper corner down, and sucked the fluid up with the same bottle. The sand will come up with the kerosene and settle at the bottom of the squirt bottle so you can reuse the kero several times.

Take a look at the worm gear on mine. When I was halfway through cleaning I realized it was damaged. It’s just mild steel, not hardened, so i actually bent it back to shape with a screwdriver. Then I used a file, diamond hone, and fine sandpaper to smooth the rough edges. You only have to worry about one side of the thread, as the saw only goes in one direction.

bent worm teeth
bent worm teeth
nasty bandsaw gearbox
nasty bandsaw gearbox
damaged bandsaw drive worm
damaged bandsaw drive worm

Make a final wash with clean(ish) kero to get the filings and sand out, then wipe with paper towels. You won’t get it all, but using gear oil (NOT motor oil) will help by allowing any remaining sand to settle out rather than getting suspended in the oil as you run your saw.

After you clean up the gearbox, replace the oil with a brass-safe gear oil. Don’t use regular automotive gear oil unless it specifically says “safe for yellow metals” or “safe for brass and copper”. I used straight mineral 90 weight gear oil GL-1 rated that I found at the tractor supply store. Some GL-4 and GL-5 rated gear oils eat brass so stay away from them unless the manufacturer specifically says it’s safe.

Next you’ll want to replace the blade and align it. Get a quality bi-metal blade and your saw will cut 100% better. I use the Irwin variable tooth 10-14 tpi blade from Enco. I think it cost about $25. Read the manual and look for tips online about aligning the blade. You will need to take off the guides at first to get the slave wheel aligned properly, but take note that the guides DO affect how the blade tracks somewhat, so you will have to account for that. Specifically the lower guide will twist the blade as to angle it toward the back of the drive wheel. This is a good thing, as it helps the blade stay on the wheels, just be aware as you tweak. I won’t get into the whole process of aligning the blade because it’s more art than science, but I will say this:

*Don’t tension the blade too much.* Some recommend really cranking down on the knob to tension the blade. I found this isn’t necessary at all. Just get it tight enough to be straight from wheel to wheel (check the return side). It should be snug, but not tight. This is my own opinion from the experience I’ve had with this particular saw. I know that bandsaw blades should usually be fairly tight, and I’ll admit to not knowing the full reason for this. I think it has to do with blade life and tracking while cutting. You can adjust for the latter with the blade guides with fairly good results, but I’m pretty sure too much tension would start wearing out the cheap parts on this saw. Blades are cheap enough to replace, but it’s a pain to start replacing parts on this machine.

Maybe I should have mentioned this even earlier, but replace the belt too. The cheap chinese motor and even cheaper cast pulleys make for lots of vibration. A link belt won’t transfer vibration like a solid rubber one. Spend the money and get a Powertwist V-belt. You will need 2′ of 3/8″ belt. You can find this on Amazon or Grizzly, but I got exactly 2′ from ebay for about $17 shipped. After replacing the belt, 90% of the noise and vibration just disappeared. I have run the saw in the kitchen of my apartment while my roommate was asleep. That’s how smooth it runs now.

Belt tension? What tension? I actually don’t tension my belt at all. I let the weight of the motor alone put the tension on the drive belt. This works in both the horizontal and vertical positions. I have never had it slip, and more importantly it eliminates any remaining vibration that would still be there after putting the link belt on.

One more thing you might consider: cutting fluid. While some people outfit their saws with flood coolant and hydraulic blade lowering systems, I find this is just overkill for my needs. I never leave my saw while cutting, and I like to set the blade pressure by hand, holding on to the handle as I cut. I keep a squirt bottle of a multipurpose non-staining, non-corrosive oil (Mobilmet 404 usually) nearby so I can put a few drops on the blade as it enters the material, but only when it really needs it. I also like to use the saw vertically a lot, so a flood coolant system would just get in the way. It’s hard to lubricate in the vertical position, so I use a stick of Castrol cutting & drawing wax. The wax hangs on to the blade better and keeps chips from loading up. That’s really all you’re looking to do: keep the chips from sticking to the blade or workpiece. The blade will cool itself on the way around.

Lastly, join the Yahoo 4x6bandsaw Group. There you can find lots of tips and modifications you might want to use on your saw.


A mathematician, hacker, fabricator, and all around do-it-yourselfer. I like building my own tools, learning new technologies, and breaking stuff.

4 thoughts on “Harbor Freight 4×6 bandsaw

  • March 25, 2014 at 11:17

    I have one of these saws and the blade doesn’t track on the top pully/flywheel it rides perfectly on the bottom one. Did you have any issues similar to this?

  • April 2, 2015 at 17:22

    Where can I buy a brass worm gear for C.M. horizontal band saw. item #63762 on name plate Thanks Russ

  • January 17, 2016 at 21:40

    Thought you might like to know why the band should be tensioned properly. The band is just a beam ~8″ long, 0.025″ wide and 1/2″ deep, running between the backup rollers with the work pushing up in the middle. It deflects up under the load. So long as the weight on the saw head is counterbalanced with the spring along side to 7-9 lb (measured with a luggage weighing balance around the tension knob) and the blade is fully tensioned to 1500 – 2500psi (this is blade manfr’s recommendation), it just bends in the 1/2″ direction. If not enough tension, or not enough counterbalance, then the blade starts to turn sideways as well. Since it cuts in the direction its pointing, when its insufficiently tensioned or overloaded it will cut toward or away from the vice depending on which way it points. 2000psi tension means a bending load of about 450 lb in the head casting. To develop that you need to screw the tension knob as hard as a normal man can do it, without using a rag or something to help. If you want to measure the tension then twanging the return side of the blade, it should resonate at ~90hz, something you can check with a tone generator/ frequency app on yr cell phone. Rgds – jv

  • September 8, 2017 at 03:32

    Oops. Noticed an error in my post above. Blade tension is 15000-20000psi for carbon steel (blue colored) blade not 1500. Bimetal (grey sandblasted color) run 25000 to 30000psi not 2500. Factor or 10 out. This means a force pulling the wheels together of about 600lb at 30000psi with a standard 10-14 TPI bimetal blade. Sorry for the mistake – jv

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