Papercreters: Re: [papercreters] Long Sad Story

Possibly. This mixer has only lasted six years+, and mixed close to half a million pounds of papercrete without problems until recently. : )

The main moving part is a Ford Ranger rear end. A differential from a heavier truck would be stronger.

I think it's more a matter of fatigue than bad design. Metal does flex, and eventually crystallize, and break. There is no doubt that fatigue caused the original blade to break. I have never pampered this mixer, pretty much the opposite. The X blade might turn out to be not compatible with the way it is mounted, forcing me to return to a single blade, which served me well. Meanwhile, I'm toying with SG's challenge to design and build a superior mixer that would be available to just about anyone with basic skills, or a little money to purchase those skills.

        Spaceman  All opinions expressed or implied are subject to change without notice upon receipt of new facts.

Carrol Reeves wrote:

Sounds like its time for a more heavy duty machine.

Greg House <ghunicycle@yahoo.com> wrote:

I wonder if the new X-blade is causing vibration problems? Perhaps that's contributing to all the failures.

Greg

----- Original Message ----

From: Spaceman <Spaceman@starship-enterprises.net>

To: papercreters@yahoogroups.com

Sent: Thursday, November 8, 2007 3:35:22 PM

Subject: Re: [papercreters] Long Sad Story

I'm definitely considering that. Obviously a X blade will offer more resistance than a single blade. The load I was mixing has some pretty hard chunks of recycled heavy papercrete and I may remove them before finishing the load. They have been soaking for several days and are still hard as a rock.

I'm armed with new bolts and lockwashers but can't do anything with them today because of other obligations. Tomorrow will give the answer, I'll check the bolts after each load to make sure they aren't loosening.

Spaceman

All opinions expressed or implied

are subject to change without notice

upon receipt of new facts.

Nick Boersema wrote: Spaceman are you sure that new blade is not trying to tell you something?

Nick

From: papercreters@ yahoogroups. com [mailto:papercreters@ yahoogroups. com ] On Behalf Of Spaceman

Sent: Wednesday, November 07, 2007 5:20 PM

To: papercreters@ yahoogroups. com

Subject: [papercreters] Long Sad Story

I've had an interesting chain of events here lately that have halted the current project for a couple of weeks. First my blade snapped, the one I'd been using for six years. I replaced that with a new X blade that mixed one load and then came off, stripping bolts as it came loose. New bolts and some cleaning of threads on the yoke got the blade back on, and back to mixing.

A few loads later I heard a grinding noise and found that the welds holding the drive shaft to the truck wheel had failed (six years old, too) or more accurately the metal next to the welds had cracked. Looking it over, I reinforced my original thought that the truck wheel was pretty thin metal, and decided I needed to make an adapter from the shaft to the truck axle. I made a few measurements and then did a sketch of the bolt patterns in CAD, making a pattern with their relative positions precisely laid out so that the universal joint bolts had the maximum clearance from the lug bolts and everything was nicely centered. I didn't have a chunk of plate steel large enough, but found two smaller pieces that could be welded together. Once I had those joined, I applied the pattern and center punched the holes. Shortly after, I found out why that drill bit set was so inexpensive. I destroyed several bits getting the pilot holes done, and ran out of suitable
bits before I finished the full diameter of the holes. I made the round of local hardware stores (MV Ferreteria and Señor Dollar), but neither had large bits and it was getting late in the day, so I decided to make a trip to town on the morrow.

At the Home Depot I found what I needed, and actually found some 7/16 hard bolts to fit the universal joint, along with various washers and nuts, including lock washers. I cut the heads off the bolts and welded them into the appropriate holes in the plate because the back of the adapter has to be flat with no bolt heads sticking out. With the adapter finished, I found that the truck was now 1" too far from the mixer since the adapter is thinner than the wheel where it mounts. The truck has been on blocks for six years, and moving it was not a trivial matter, but I got it done. Back to mixing.

Then I noticed a strange noise from the rear of the truck, and panicked. Had I managed to ruin the axle bearing? No, turns out that the brake drum was not held in place by the adapter plate as it was by the wheel and it was flopping around, so a stack of washers was needed on each lug bolt to secure the brake drum. OK, back to mixing. Wait! Why isn't the slurry moving? Well, because the blade has come off again, in spite of really putting torque on the bolts last week. Now I have one bent bolt, and one partially stripped bolt. It'll be dark in an hour, so I'll wait until tomorrow to go to town, since I have to go tomorrow anyway for something else. I now declare it beer thirty, I'm done for today.

Spaceman All opinions expressed or implied are subject to change without notice upon receipt of new facts.

  

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Friday, November 9, 2007

Re: [papercreters] Long Sad Story

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