HF 4x6 - Time to replace?

Herbie555

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Hello all, this is my first post here, but this seems like the place for an honest answer.

I've hit a decision point with my well-worn 4x6 bandsaw. I'm thinking it may be time to replace it, rather than trying to refurb my current unit, but I want to make sure I'm not "wimping out".

Background: I've used and abused my Harbor Freight saw for more than 10 years. Aside from some rudimentary adjustments, and an occasional blade change, I'd done nothing to it. I was a novice, and hadn't read the (many) forums for these tools, so I did zero in terms of cleanup, and never even changed the gear oil, etc. Recently the motor finally failed, so I tried to replace it with a 1/2hp 1800rpm unit I had on hand. Unfortunately it wasn't a direct fit, the motor had a bigger frame and output shaft, so fitting it involved boring and re-broaching the motor pulley and notching the motor's base plate where it interfered near the tension-adjusting bolt on the mounting plate. At that time I undertook a slightly more serious attempt at aligning the blade guide bearings.

Since that replacement/adjustment, the saw just isn't cutting. Like, at all. A test cut through some 1/8" angle iron literally killed a brand-new bimetal blade and wouldn't even finish the cut after swapping back to the previous blade that was working "well enough" prior to the motor swap. To be clear, the saw was running for minutes on a cut that I expected to take well less than 60 seconds. Yes, teeth oriented correctly, belt position and feed pressure in the range of what I've used previously, etc.

Not sure where I went wrong. Willing to admit improper blade tension probably killed the new blade as much as anything, but I suspect this motor just isn't a good match.

The problem now is that while I could buy a new motor (and probably a replacement pulley), I'm looking at how worn the guide bearings are, and considering the fact that I've abused the worm gear, etc., and the math is starting to get stupid. With coupon, a new HF saw can be picked up for ~$200, while a new motor, pulley, guide bearings, etc. will easily add up to $160+shipping and that doesn't address all the other little parts.

I'm typically a "repair, don't replace" person, but the economics of this situation seem to dictate that the time to refurbish + unknown future failures aren't justified by $40 savings.

Thoughts? Thanks.
 
Hi Herbie,

Welcome to HM, we are glad you joined us in the fun.

So, if you were to replace are you replacing with another Harbor Freight unit or are you thinking of doing an up grade? Same size unit or bigger?
 
Thanks Randy.

If I were to replace, it would almost certainly be another Harbor Freight 4x6 unit. Nothing in the budget for an upgrade, and have a project pending where I need to get a machine up and running again soon. Size-wise I haven't needed anything bigger and my shop isn't huge, so a bigger unit would be hard to justify.
 
First, Welcome to HM.

Second, regarding your cutting issues......Only because I've done it...... Are the blade teeth possibly facing the incorrect direction?

Regarding a new HF saw, I have two. An older saw (10+ years), that I was recently given, and a newer saw that I purchased (last 5+ years). They look the same, but the quality is quite different. My older saw has heaver castings, better blade alignment/tensioning, adjustment knobs vs bolts, and the Blade Guides have more adjustments. The biggest is the blade guides being able to rotate along the linear axis of the blade, so you can straighten out the blade twist. My newer 4x6 lacks this. With a lot of work I've been able to get my newer saw to cut-off fairly straight. But the older saw still cuts straighter and is easier to get cutting straight after a blade change.

Fixed Bandsaw.jpg

Newer HF 4x6 Bandsaw

Adjustable Bandsaw.jpg

Older HF 4x6 Bandsaw

You might want to compare your current saw to the newer HF saws, to see if you current saw has the differences I've experienced with mine. Because of the quality differences with the older saw, I've chosen to rebuild it and make it my primary "horizontal cut-off" saw and my newer HF 4x6 saw will be left in the "vertical table saw" set-up, for when I need to do free hand cuts. If your saw has the better castings and/or better adjustment capability, that may influence your decision to rebuild or buy new.

Hope this helped?
 
The weight of the new motor may be different and changed the actual downward pressure on the blade. I think the desired number is 6 pounds, measured with a spring fish scale (or similar) lifting at the blade tension knob. Are both motors the same RPM?
 
Thanks all.

Yes, I'm certain I had the blade teeth facing correct direction as I forced myself to check the teeth against the little sticker on the bed at least four times (while trying to figure out what was going on).

Thank you for pointing out the changes in the design - I wasn't aware, and that's certainly a step in the wrong direction if they've taken out the adjustments. Yes, mine is old enough that it has the adjustments as in your second image.

I'll try to measure the feed pressure. I'm occasionally guilty of throwing a little extra pressure on the arm, but knowing that there's a spec gives me something to measure against.

Regarding RPM, I believed the motors matched up well. My replacement motor is 1/2hp, 1800rpm, 8.5A at 115v. The original motor from my HF saw was labelled as "1hp, 1700rpm, 6.4A". I believe the 1hp figure about as far as I can throw the old motor, but if 1700rpm is accurate, then I should be running around 6% faster now. Using the fastest step on the pulleys, that should be around 212fpm, which should be inside the envelope for a 10-14t blade when cutting thin mild steel.

I don't have a convenient way to measure the real FPM, but I could try to mark the blade and count revolutions over a fixed period or something.

I suppose I should try once more with another new blade (after measuring feed pressure), just to make sure that I didn't compound operator-stupidity with too many changes at once. I'm willing to invest in new guide bearings, etc. if the new motor can be made to work.
 
I've also be reading up on blade break-in, and it seems that's one more thing I've been doing wrong.
 
Is your motor running the correct direction?

Sent from my SCH-I545 using Tapatalk

Yes. Confirmed with blade markings on bed (and with the arrows I drew inside the belt drive housing prior to swapping the motor.)

Thank you for checking, though. The change in performance is so significant it almost has to be something stupid like this.
 
Couple of things...
I'd set the speed up on the middle speed (run it slower). That's where I run mine.
Put more downward pressure on the saw frame. You crank the handle counter clockwise on the spring tension arm (remove tension) to increase weight on blade.
Is the range of travel correct. The bolt that adjusts it is way back on the plate the motor mounts to if I remember correctly.
Are the two rollers on the back edge of the blade doing their job?
Without any material in the saw make sure the saw blade/frame doesn't bind anywhere in the needed range of travel.
Is the auto shutoff adjusted correctly and not binding?
Will it cut a piece of ¾" wood?
Are you trying to cut crap bed railing?

If the blade continues to move without slowing down and the teeth are sharp and pointing in the right direction it is going to cut. It has to be something simple and you are going to bang your forehead when you find out what it is.

P.S. I have had all of the above problems!
 
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