"Chinese Iron Bullets"
Harbor Freight 4x6 horizontal/vertical metal cutting bandsaw #93762. A not-so-technical review.
Goal: There's a lot of information available on the Harbor Freight (HF) 4x6 bandsaws and I'm just adding my two cents. I'm including a product review and some suggestions before flipping the on-switch.
Background: I finally got tired of hacksawing metal to fit my HF mini lathe and micro mill; the final straw was spending 3 hours sawing scrap castings for a little forging project. Armed with a 15% off coupon and being on sale, it was time to pull the trigger and buy a metal cutting bandsaw. Four things you must know:
1. Don't buy a large HF tool expecting premium quality or safety unless it's Agency listed.
2. If used industrially, it will most likely fail just after the warranty.
3. Your tool can last longer if upgraded (time and money).
4. Metric parts are the rule. A lathe and mill may be useful for making custom parts.
Don't send me nasty e-mails. I have "China's Little Machine Shop" and most of my equipment and tooling is from HF and the defunct Enco. The learning experience, inherent need, and lower costs are the reasons for buying these tools. I'm not typically buying German, American, Polish, Czech, or Taiwanese quality and don't expect it.
I've been eyeing these saws for several years, and the numerous posting on bad motors turned me away. However, this new model with a massive 1HP motor piqued my interest. Finally I got the chance to see it at the store and I compared it to an older display model. It seemed a general improvement over the prior design and it was on sale for $159.99; I had a 15% off coupon, thus $145 including tax.
Construction: The packaging was quite good, and oddly unbalanced. There was a small rubber extrusion bouncing around in the box and tucked in a corner a very large painted and bent plate with one hole. These parts are not in the manual and e-mailed HF for clarification several times, with no response. I suspect it was for shipping protection. The manual is straightforward with assembly, but contains prior model photos.
Assembly: Before starting, place the top assembly on the floor or workbench and place a 2x4 under the bottom front edge of the casting (tilted back). Open the gearbox since many complain of casting sand. I didn't find much sand, but eventually did find something more troubling. Also the casting, cover plate, and gasket tolerances are terrible. The alignment suffers and it appears the casting is finished with a handheld angle grinder. The inside of the cover plate was also pitted with rust. Not pretty for something new.
Use an old turkey baster and suck out that BLACK & NASTY oil. It's laden with rust, iron dust, sand, and a CHINESE IRON BULLET! Note the little brass sparkles in the oil. Use a 1/4-cup of kerosene in the box and a chip brush to dilute the sludge. Remove that mixture and use a rag to dry. Inspect thoroughly! I first thought that my CHINESE IRON BULLET was a lost screw. Note the paint inside also has embedded grit.
Use a small brass brush wherever you can to loosen any grit and paint inside the box. The worm gear was covered in carbonizing and I needed to use a steel brush on it. Brake cleaner may help with paint removal and a final rinse, but be careful with oil seals and over-spray outside the box! I noticed the surface finish was horrific (somewhat evident in the photos). It was deeply pitted, scarred, and nicked. I used jeweler's files to smooth out the lathe chatter from the worm to lengthen the life of the brass gear (remember the brass dust). To improve the gasket seal, I filed the box's rim to a suitably flat and even surface with a fine 4" Nicholson (messy and time consuming job); vacuumed, and repeated with another kerosene wash. After a final mop-up, use compressed air to clear out the threaded holes. No further worries with leaks.
Turn the worm gear pulley by hand. I found unusual binding (not caused by surface finish). I wouldn't recommend disassembly, but to remove the brass gear you really need to plan on going vertical and removing the blade and drive wheel. BE VERY CAREFUL WITH THE OIL SEAL. You'll need a gear puller on the drive wheel. It seems the shaft bearings weren't properly aligned (over-pressed). I disassembled the gear-shaft, cleaned things up and re-aligned it. In removing the gear, the 5mm spring pin shattered (bad pin, not tempered properly). The brass gear and key is hammered violently at the factory (see dings) and the shaft is very tight on the gear and drive wheel. It really needs a retaining clip, like the drive wheel.
I used ~250ml of an 85W/175 Gear Lube (Wal-mart Tech-Lube, EP-5 rated for copper & bronze). It's a nice medium honey color. Re-lube the box and fill to the bottom edge. The 2x4 (tilt) provides extra oil, especially when going vertical. Close it up and do a final cleanup. You can then follow the directions. **
The base's fastener and assembly sequences aren't exactly right from a practical standpoint but it's mostly preference. Assembly shouldn't take anymore than about one hour, and you will need help. All of the weight is in the motor and castings (IT WILL TIP!). I suggest using a 2x12 between two sawhorses. Balance the top assembly cross-wise on the board, clamp to the board, and leisurely attach the base. Then unclamp and "two-man lift" the saw, using a third party to slide out the board. If working alone, I don't think a hydraulic lift is a good idea unless you lock down all your straps so they can't slide or shift.
Conclusion: I'm sure that it will give me a useful life, but I suspect that within 2 or 3 years a bearing or two will need replacing (629ZZ already on my shopping list). At first I thought that the motor would outlive me, but a "switch bouncing" episode may have overheated some windings (smell apparent). Which may explain the common "smoked motor" complaints. The switch should have a longer throw and I may replace it with a heavy-duty safety-key-free toggle, since children don't play with my toys.
Don't trust the factory blade alignment. The most critical is that of the lower guide assembly. Plan on a couple of hours to get it right. Afterwards I found a few problems. The cutting axis seems to move inwards by 1.5 degrees, and once properly adjusted the lower guide-housing/blade shield bumps the base.
To improve the clearance/interference of the lower guide I re-adjusted the pivot bolts (two large socket head cap screws attached to the pivot arm assembly) and filed about a 1/16" from an outcrop in the casting. I re-stamped the blade shield housing's countersunk screw holes, placing the housing in the proper location. I also feel the the blade cover needs a critical safety upgrade and I'll be adding some sheet metal.
Some users complain about a tilted cutting axis problem and I tweaked around, finding that my critical problem lies in the lower casting cutting surface. It's 0.019" higher on the outside lip (steps up), so it tilts the workpiece. Surfacing castings is a very simple factory operation and don't know why it's not properly done? I also wonder if the pivot was bored to this inaccuracy which explains the 1.5 degree offset?
A Few Notes: After assembly, build an undercarriage with large hard-rubber wheels. The cheap ABS plastic wheels create instability AND can damage a nice shop floor. **The motor is so heavy that the imbalance makes the unit a hazard. An undercarriage should be offset further on the motor side by at least 6", to improve stability. And ideally 8" of wheelbase offset away from the motor end or 20lbs. of counterweight on the switch end would help (consider using the wheel-axle assembly for this application). The base's corner braces help with bolting to an undercarriage. The drive wheel cover allows for an "errant finger" to contact the blade; correctable with a small sheet metal guard added to the casting or cover.
I considered a sight glass on the gearbox cover and may still do that project to simplify oil changes and keep an eye on that worm gear. JET recommends replacing the oil every 6 months in their saws. I think it's a better idea than HF's once a year. I'll probably do it after the first 3 months to check on wear. -5/27/2007-