Skill Band Saw 3386 -1.3 Hp Treadmill Motor Retrofit

[Ulma Doctor]

ACT 5

i got the saw in a relative state of readiness today,
although i have been working on the saw for a week off and on.

since the video,
i needed to get an electrical enclosure and contemplate mounting solutions.

the first thing i did was come up with a reference area to measure where everything was going to mount.
luckily the main casting had a trapezoidal feature.
the casting protrusion was going to be my mount point for the electrical enclosure.
the protrusion is a thick part of the main casting.
on the interior of the casting, there is a mount point for a brush for the lower wheel to keep chips debris from derailing the blade

i drilled and tapped the holes to 1/4"-20 tpi


i cut a piece of reclaimed 1.5"x 1/2"x 6" 6063 aluminum and laid out the mount points on the electrical enclosure.
i transferred the holes and drilled the enclosure for the mount.



i drilled a 2-3/4" hole for the fan inlet and sandwiched an improvised nylon scrub pad filter and a small piece of expanded steel to keep the scrub pad out of the fan.
i tapped the fan mounting holes to #10-32 on 3 holes,
(the 4th hole had interference with the enclosure mounting )
the fan was sufficiently captured with 3 screws, so i'll live with it


i mounted the KBMM-118 and the potentiometer to the enclosure, and plumbed rest of the the wiring through

when i made my video, i was ignorant to the fact that treadmill motors have a fan integral to the design of the flywheel.

that fact was pointed out ,astutely, by a good friend.
he made recommendation of keeping track of the motor temperature.
thanks for the thought and concern!

so with this in mind, i considered ducting the control box air wash through the dc motor.
i prepared by using a high volume/high speed 2-3/4" 115 vac fan,
to get a large volume of air circulating both through the control box,as well as using the clean air to cool the motor.

the wheels were set in motion,
i drilled (read: and hacked) a 3" exit hole on the aft side of the enclosure.
i used commercially available 3" water heater exhaust expanding aluminum duct and sheet metal couplings,
to rig up a 180° cooling elbow , from the big box store.
the fit was glove-like over the DC motor, i just had to notch for the carbon brush holders.
i was able to use a 3" clamp to hold it on the motor and box.
i added some anti-friction wrap on the potential wiring rub points.



here is a side view,
the potentiometer is in the center knockout port.

i used the wrong port of the enclosure to hold the potentiometer ,
it was messing up mounting the incoming power to the enclosure.
there was only a 3/4" knockout there, so i fabbed up a bushing/spacer and washer for the 1/2" electrical fitting.



here is a picture of the control box, motor, and (questionable) cooling system, looking to the southeast




and one shot looking straight down on the enclosure



i taped over the enclosure knock-outs in an attempt to make the box as airtight as practical.
i still may add a gasket to the top cover, not that it fits poorly,
but just preemptively addressing the leaking cooling airflow to the motor.


let me tell you all, i did things the hard way on this build.
everything took twice as long as expected, but the performance is flawless

the retrofit, was less than flawless-
but, i'll take performance over appearance any day of the week

i'll be adding fuses for both the ac and dc circuits,
so the thread isn't over quite yet...

see you all on the next episode,
same bat channel, check your listings for times
drink your Ovaltine!!!

 

[middle.road]

Inspiration! I like the cooling system, ingenious.
I've got three in a round-tuit crate - want to do the Logan, the bandsaw, and a Craftsman 4x36" belt sander...
Missed out on two more donors at an estate sale this past weekend, but then I'm out of room in the shop (as usual).

"drink your Ovaltine!!!" -hehe

 

[Ulma Doctor]

here is a snapshot of some test cuts!




lol,
here is what it really cut, (less the spark plug airplane)



thanks for reading!

 

[Ulma Doctor]

Update:

After tearing up lumber for a few years with the lil beast,
i carelessly rubbed too hard against the poorly planned exhaust tube and the interfaces between the DC treadmill motor , the tube and the electrical enclosure.
the end result was a failure of the cheap coiled aluminum tube, due to substandard execution of an idea.
here are the offending parts that were the interfaces



as you can plainly see,
about 15 seconds of design consideration (and half that time in construction) yielded a functional, yet pathetic cooling system.

i decided to do things differently.
i hand sketched, the designed 2 interfaces for the new and improved Kool System, on Tinkercad-
then 3D printed them on the Ender5 in PLA



one adapter is flanged for attachment to the electrical enclosure with screws,




the other slotted to mitigate interference witht he DC motor's brush carriers. to be retained with a 3" hose clamp.



the same cheap 3" aluminum exhaust tube was retained, but shortened to accommodate the new retrofit .

Friends, I give you the Kool System for the Skil 3386 assembled and fully functional-albeit years after conception !







the system works very well, thanks for reading!

 

[brino]

Hey Mike,

Thanks for the update, however:

After tearing up lumber for a few years with the lil beast, i carelessly rubbed too had against the poorly planned exhaust tube and the interfaces between the DC treadmill motor , the tube and the electrical enclosure. the end result was a failure of the cheap coiled aluminum tube, due to substandard execution of an idea.

.....or perhaps too much ovaltine!

as you can plainly see, about 15 seconds of design consideration (and half that time in construction) yielded a functional, yet pathetic cooling system.

I have seen much more pathetic cooling systems on PC motherboards and graphic cards that have NOT lasted the nearly five years that your "questionable" version did.

My money is still on you!

Brian

 

[Ulma Doctor]

Hey Mike,

Thanks for the update, however:


.....or perhaps too much ovaltine!



I have seen much more pathetic cooling systems on PC motherboards and graphic cards that have NOT lasted the nearly five years that your "questionable" version did.

My money is still on you!

Brian

You are way too kind, but thank you!