Tanque

I ordered a number of Mato's 3:1 brass gearboxes for my 'upgrade program' for PzKw III, StuG III and KV1.

My impressions of these gearboxes are mixed.

The first set I unwrapped had the following defects.

Output shaft badly bent on one unit.

Vertical section of frame where motor mounted was not at a right angle to base plane on both left and right units;
one being so far off that the pinion gear engaged the driven gear at an angle.

Center line of motor mounted at improper distance from driven gear center line so that the gears barely meshed
on both units.

Output shaft bearings were skewed on their mounting holes.

Motor pinion gear set screw hole thread nearly stripped.


With these problems when I lightly lubricated the units one tried to draw 4 amps at 5 volts. Shutdown.

I corrected all the problems ( save the pinion set screw hole) indicated and the units ran well
drawing .45 amps at 7.5 volts with no load.


I made up my mind that going forward I will use only the models themselves. Mato's / Heng Long's motive units
quite honestly stink not to put too fine an edge on it. At the price they sold these for there should have been much better
QC and execution of their construction. I think the part that bugs me the most is I trusted that these would be batter
than they are so I purchased 3 instead of more wisely 1 to see how they are made. I will make them work but I shouldn't
have to. I disagree that the output shaft should be brass as well as thin as it is.

I've uploaded a photo of the gear spacing I mentioned, that between motor spur gear and the driven gear.

Folks can poopoo Tamiya's cost all they want. Hang Long/ Mato makes a good product but they have yet quite a ways to go
to even come close. It would be better for us if they just sold RC capable kits and leave the other components to us the
builders. The sooner they realize this the better for everyone.

I am rather disappointed with these units.



Jerry

Tanque

It appears that I inadvertently managed to open the worst examples of the Mato gearboxes I received.
The other two sets weren't anywhere as bad and even allowed sufficient adjustment of the motor position
to minimize the gear backlash.

Additional aspects I noted. I give Mato thumbs up for taking the time to imbed steel dowels at the junctions of all their composite gears
in the driveline. That was uexpected and I've not seen another maker yet do that. The gears themselves seem well executed machined
brass. I ran all 6 gear boxes up to 11 volts and they seem tough albeit under no load. Starting current, again under no load was consistently
around 1amp. I make a rudimentary brake to put a load on one of the units and the brake broke before I could get the gearbox to stall. I read
the current to be around 2.0 amps so it seems ok.

The one change I made on all 6 units was to file a slight flat on the motor shaft to give the pinion set screw a good purchase. Some may feel this
needs to be able to slip as a safety, I do not.

I could have happier without the shiny plate job they did on these units; neatly formed plain or Zn coated steel would have been better.
The chrome look doesn't really cut it, appears cheap.

The only thing I can't predict is how long the units will last, brass gears not being my first choice. I would have preferred steel gears of course
but better, read accurate machined not crudely die molded, zinc alloy, may have been better. I will making certain these have first quality
lubrication when in the field. I tend to baby my tanks so perhaps I will get a good service life.

Jerry

philipat

Glad to hear it wasn't a complete downer. Did you have to tweak the later sets, too? Or, were they GTG out of the box?

Any pictures of the dowel? I'm not quite understanding what you mean.

Thanks for the review.

Tanque

It is a form of key to lock two parts together. Instead of a woodruff or square key a steel dowel
or rod is used.

I've not taken a contemporary Tamiya gearbox apart so I don't know if they do this also. I have repaired
gearboxes using this technique, it is very common. Most all of my larger IC engine capable transmissions
use a larger version of this. I know some of the older large ( FP-S14 ) Futaba servos also had rolled pins in
this function. I have no doubt many many more rc related items use similar construction. It happened to be the first time
I saw it in a Mato / Heng Long type product.

Jerry

You may see the steel key here:

Perry S.

Thanks for the review and for posting that picture. Too bad their quality isn't there yet. Maybe over time as with their tanks.

I'm more thankful of the pic of the pin. I have a lot of applications in other hobbies where I could use a keyed shaft and don't have the machinery to do it. I think I can do something like that on my lathe and drill press.

Perry

MassiveOverkill

When I ordered my 2nd generation Mato's from Phil, one side was silky smooth, while the other side had horribly-cut gears, which I had to send back.  The replacement that Phil sent back was I'd say 95% as good as my good set.  I can now turn both sides by hand with the motors installed.  I'm hoping that some early beta batches got sent out and mixed in with more refined ones, intead of it being a mixed bag where quality control just sucks and depending on which underpaid/disgruntled worker happened to be working the machinery the day your gears were being cut.

Those of us with Jagdpanthers had clearance issues, but I later discovered that this is more of a Heng Long problem and not Mato.  The gearboxes sat too high in my newer Jagd chasis, which would have required modifcation of the standoffs, while my older Jagd chasis, the gearboxes fit perfectly.  I'm basing the new/old classification of the chasis based on the electronics that came with each.  My new Jagd had the updated RX18 module with the additional MOSFET board, while the older chasis had the older RX18 that had alot of electrical whine.  

Of course it could be that there isn't a newer/older Jagd chasis and this is just another result of HL's crappy quality control, but I'm more inclined to believe it's a revision change as a mold is a mold, the dimensions of the chasis shouldn't vary much unless they're using multiple molds..........it's not like the plastic chasis is a machined part like the gearboxes.  

Here's the other thread on this gearbox:  http://www.rcuniverse.com/forum/m_10449248/tm.htm

Please ignore the unproductive flaming in it.

 

Tanque

A person doesn't need a lathe to use this technique. A decent drill press and a suitable selection of drills is required.
You could use sections of steel finishing nails ( I have) as dowels making sure the hole you drill is appropriate.
Just locate a hole on the junction of both parts to be secured so that 50% of the hole is on either part and you are done.
The hole is not to go through the parts; if you penetrate through to the gear faces they are ruined. This I believe
is why this was generally referred to as a dowel and not a pin as it is a one way sort of installation- you cannot easily
remove it as you could with a pin. True steel dowels are used for locating parts together to maintain proper alignment;
alignment not being really at issue here. I use the dowel designation as opposed to key as keyed parts are generally
meant to be able to be taken apart for maintenance but this sort of mechanism is not. I'm sure either using the term key
or dowel will get the point across.

This a better alternative to soldering in most cases as there isn't change of hardness due to heating the part.


Jerry

candycab

This is probably a really dumb question my part but how do these stack up to Asiatam boxes ?

I'm guessing the Asiatams are higher quality overall ?

I had been waiting for someone to buy and try the new Matos before I pick up two sets of one or the other.

Thanks for letting us know how yours went, I appreciate the info 

Tanque

It isn't a dumb question. I don't have am Asiatam unit to compare with. After seeing how the Mato units are made I am comfortable
saying that on the whole I'm no longer unsatisfied I bought them. When I first posted this topic I was expecting all 6 unuts needed
as much work as the first. I am pleased to say that isn't the case.

When I made the decision to buy them I wanted not to have to spend the time making units myself and these met that criterion;
the slight adjustments not withstanding.

The only unknown is how well they will hold up over time. Surely these would not hold up to the rigorous driving I hear some chaps here
subject their machines to. Brass gears likely will not hold up as well as hardened steel gears. If you are a moderate to granny operator like I
am they'll probably outlast us both. The ball bearings on the output shaft are quite small; also unknown is how these parts will hold up to
lateral forces under load.

I'm rebuilding my models to use Asaitam's metal hulls which I'm hoping will provide a bit more rigidity and aid the life span of the units.

Jerry