Central Machinery 1 1/4 Cubic Ft Cement Mixer

After some truly back breaking work demolishing a sidewalk, lowering the ground level and adding a few concrete replacements (small set of stairs, retaining wall, etc) I found that mixing concrete the traditional way, with a hoe and trough, to be a good way to finance my chiropractor's new pool.  After designing a set of stairs that would be necessary to enter the side door of my house and calculating the 2000 lbs of concrete it would take to make them, I decided it would be best to eliminate/automate as much of the work as possible.  Solution: cement mixer.


First stop; eBay, CraigsList, wanted ads, I don't want to buy new for something that would likely be around for only a job or two before I sold it myself.  Results were poor as the price was $150-$200 dollars for mixers that looked questionably functional at best.  Second stop; Harbor Freight where I found the Central Machinery 1 1/4 cubic foot portable cement mixer recently marked down from $179 to $159.  Not bad, even cheaper than some of the beat up used junk I saw in personal sales. Still not 100% sold, a bit more than I was looking to spend, until....the July 4th 25% off coupon came in my email and this bad boy could be mine for a mere $120, SOLD!

My biggest fear as I drove my little Grand Prix across town to purchase the mixer was "how the heck am I going to get this thing home?".  After arriving at the store I soon found an assembled display model for reference.  "This might fit" I thought to myself, not horribly large, maybe some disassembly required, but do-able.  I soon had the stocker retrieving a new unit from the back and had to read the box twice before I believed he had the right item.  This box was so small, the size of a small TV set, it was a bit heavy (72lbs) but fit in my trunk with ease.

First thought as I opened the box; "wow, this thing will take some assembly" as there appeared to be many pieces interwoven with packaging, this was going to take more than the hour I allotted to assemble what had appeared in the picture as a fairly simple device.  I began unloading and unwrapping piece after piece making sure to take a mental inventory so the instructions would make more sense.  The pieces have a decent heft to them, a feeling of sturdiness I did not expect for $120.  I soon had too many pieces strewn about to believe this was a good idea so I decided to work through the instructions one picture at a time.  This is where I soon came to my first issue with this product; the parts did not match the instructions!

Starting with the wheel base I soon found the pictures in the assembly guide were slightly different than the parts I pulled from the box.  I noted the upward angle of the welded support brackets was similar so I began assembling with that in mind, it worked.  No big deal, crisis averted....or maybe not.  There is one large bag with several different bolt lengths and widths as well as a healthy assortment of nuts and washers, enough to make you scratch your head.  I've done this kind of assembly before, I'll just flip to the back of the book and refer to the parts map to identify the proper bolts...no luck, just a list of parts included in the bag and a weak blow-apart diagram showing the same erroneous parts that were in the pictures.  Solution; best guess time, I would take educated guesses based on the length/width needed as well as the number of a particular part needed (if I needed four of a particular bolt, don't pick one that would fit if there are only two in the bag).  I began hand assembling and loosely tightening the bolts as I knew I would be revisiting them all after I had done a dry run making sure I was using the right parts in the right places.
As delivered, note the alignment of the blades
Making my way through the assembly I found another parts and picture mismatch; the mixing blades.  The item pictured was so far off from the part supplied that I only figured it out by elimination, I had two "doo-dads" that must somehow be mixing blades because nothing else was even close.  I put these to the side as I assembled the upper and lower halves of the mixing drum.  This takes eight bolts and nuts with a rubber seal in between, a seal that is supposed to be glued in place and as the instructions say "glue not included".  You know what else wasn't included?  A description of what kind of glue you are supposed to use.  Elmer's?  Wood glue? Super-glue? Epoxy?  I suggest a clear silicon. But...before you glue....make sure you can fit you mixer blades in.  As I found out, there is no alignment marks and the drum can be assembled in eight possible ways (six erroneous ones).  It took several re-alignments and flips of the blades to figure out exactly how they were meant to be connected.  There are two missing bolts in the bottom of the drum and two small holes in the upper half that must be aligned just so that the oddly twisted blades can reach both sets and be securely fastened.  Viola, much French aside (I do not speak French), the drum was assembled.

The next major section; the motor box.  This section would house the electrical motor that would save my back by mixing all that god-awful concrete that was to be delivered tomorrow and I got my second fear at this point; a light weight box that felt like I would bend it in frustration if this part of the assembly went anything like the first parts.  Again, I found a portion of the instructions that looked nothing like actual parts, but luckily by this time the pile of parts was relatively small and took little second-time engineering to piece together.  Note in the picture the small piece of black plastic between the motor box and the frame.  This piece is not in the instructions anywhere, is easily considered some odd piece of packing garbage and is entirely critical to the stability of the motor box.  After figuring out the only two long bolts in the bag go through an adjustable motor mount, through the side of the motor box, through the little black spacer and through the metal mounting plate (along with washers and nuts) I became a bit more confident with the rigidity of the motor box.  A very awkward portion of the assembly comes at this point;  the motor must be mounted securely on the motor mount attached to the mixer at this point but it is wired to the other half of the motor box which has not been attached.  This makes for an odd three-handed assembly moment if you know what I mean. After sealing the motor box sides together with the three smallest bolts in the bag, the motor box now has a more acceptable solid feeling.

Last but not least, way not friggin' least; the pour handle. Simple in concept, just shove a spring in the handle and bolt it to the main axle right?  Hell no.  The assembly on paper is just as described, the cussing, sweating and shoving to compress the spring while the bolt is fed through the handle with your extra set of hands....well that never made it in the instructions either.  I can tell you I was more than tempted to leave the spring out as the handle seemed to work pretty well without it, don't.  The spring is very key in keeping the handle in place during mixing and pouring, it should not be left out no matter how good your French is getting.

Ta-da a mixer is born! Sort of.  Time to pull each bolt out one by one, add washers and lock-nuts then tighten fully to avoid usage dissasembly.  After another hour of fun, the mixer was finally done, and kinda cute too!  The concrete would be here in the morning and I could try this bad boy out.  Time to sleep, I would need it.

There I was, a pallet of Quickcrete a garden hose, pre-built forms and a shiny red mixer, what could go wrong?  My first thought; get rid of the 1/2 bag of concrete I had from a previous pour as a christening test.  Dumped it in, added water, flipped the switch and coolio, it worked.  Moving the drum alignment from perfectly vertical to about a 45 degree incline allowed the concrete to tumble as it mixed and it mixed well.  A quick pour into a five-gallon bucket, a trip to my form and we were ready to get busy.  I turned the drum back to a vertical position so it would be easy to fill and dumped an 80lb bag of concrete in.  It was a 1 1/4 cubic foot mixer and 80lbs of concrete is only 2/3 of a cubic foot, I had 7/12 of a cubic foot to spare for water and tumble right?  Nope.  It fit all right, and the water went in fine, but when the switch was thrown all I got was a loud hum followed by a small "pop" as the breaker blew.  @#%!!! this thing can't mix a full bag of concrete!!  Yet again, another solution to be made; only mix 1/2 bags at a time.  This turned out not to be so horrible as lugging buckets full of 80lbs of concrete would likely have killed me as I am no spring chicken any more, so 40lbs at a time would be something I could live with.  I could live with it, if it would happen, 40lbs is apparently too much for the little engine that couldn't.  The motor box became rather hot after a few small loads of concrete and lacking a starter could not move the drum once the concrete was in place.  Solution; turn the motor on first and dump the bags of concrete in while the drum was spinning.  OK, this worked a lot better in my head than it did in practice, DON'T PUT THINGS IN THE MIXER WHILE IT'S ON!  This resulted in a a toxic cloud of concrete dust and a near miss of pulling my hand in the mixer, off goes the weasel.  Solution two; be my own starter.  After pouring 1/2 bag of concrete and spraying the hose in the drum for a good ten-count (more accurate of a measurement than you might think), I would give the drum a tug with one hand and after moving a few inches I would flip the switch with the other hand.  Surprisingly this worked stellar for the long work day ahead.

PROS: Price was unbeatable, durability not bad.
CONS: Instructions are just short of worthless, motor is under-sized and lacks a starter.
OVERALL: Aside from the relatively minor frustrations and required work-arounds, I'm quite happy with the mixer and I'm sure the next guy will be too!




6 comments:

  1. Thanks for a very helpful and detailed write up

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  2. You're very welcome. Stay tuned for my upcoming Harbor Freight dust collector write-up as soon as I'm clear of the holidays and an upcoming corporate move at my regular job.

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  3. Trying to assemble the mixer. Stuck on part where handle with inserted spring has to be pushed down on arm axial to match holes to feed bolt through.I'm not superman enough.Any suggestions to make job easier? Would heating spring provide more give?

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    1. I wouldnt suggest heating up the part to get it to bend some way it wasnt meant to. I remember the instructions were not 100% for this guy and I remember some issue with the spring but it has been awhile. I do remember having a few times going through the instructions and basically trying a few different ways to assemble. Basically talk to the parts on how they want to be assembled not the instructions when they dont make sense.

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  4. I'm working on the mixer blades right now, made it OK to this point but the blades don't seem to line up right, you shouldn't have to unbolt and rotate the drum, it should line up with one of the holes on the bottom. I'm close it just wont sit flat on the lower drum.

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    1. It's been a few years since I assembled this and i remember the instructions weren't 100%. I don't remember anything super tricky about the blades, just make sure you don't do anything radical that could damage the tool or make it unsafe to use. If you are really stuck, I would suggest contacting Harbor Freight support.

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