Introducing "Little Mac" a 3-1/2" Gauge electric switcher

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chooch
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by chooch » Thu May 19, 2016 8:31 pm

Marty of FWF,
I`m not sure what a Barber truck is never mind me trying to post photos either. :-( But my Question is, how do you remove a Pressed in bearing from a side frame journal. I have some 1-1/2" OLD Park type trucks with Double row bearings pressed in. Some had small holes already drilled in the Back of the side frame and some I had to drill holes at the outer edge of the bearing area to help punch them out.
Some bearings were worn enough I did make a little rinky-dink tool that helped some times, other times I had to break the bearings. Just asking in case.
Thanks, chooch
----------------
3/4" Barber Truck. Fully CNC'd from 6061 billet aluminum.
Full ball bearing (not needle). Full CNC'd steel axle from prehard 4140, with unique "no bind" geometry. So bearings are pressed into the side frames, yet the axles easily flex.

Harold_V
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Harold_V » Fri May 20, 2016 1:50 am

Marty of FWF wrote:I seem to be pixels challenged. Any hints?
Can you be more specific? If all you have to do is resize them to get the pixel count down, have you tried using IrfanView? It's a free download and does an excellent job.

Posting pictures on this board is dead easy, and can be accomplished two ways. One is as attachments, the other by being linked, with the picture(s) hosted off the Chaski server. In both cases, the picture should not be larger than 1,024 pixels in width or height, and should be of reasonable file size. Mb and larger pictures are generally not required, and certainly not appreciated, as they consume a lot of space and are difficult for those with slow speed connections to view. In some cases, a thread can be rendered impossible to view for some folks, due to pictures being too large. Stops a slow connection dead in its tracks!

You'd do yourself a huge favor if you'd follow this link:
http://www.chaski.org/homemachinist/vie ... =8&t=96007

Need more help? Ask. We're here to please.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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H&NERY
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by H&NERY » Sun May 22, 2016 11:38 pm

More progress, painting is done! Now I have to install the headlights and a few details.
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Marty of FWF
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Marty of FWF » Tue May 24, 2016 10:44 pm

I must say, that is really a nice paint job.
And just a heads up, on my last time at the track, I had the main sprocket on the jack shaft slip. Apparently the grub screw is softer than the stainless steel shafts. So I removed the screw and spot drilled down through the grub screw hole into the shaft to give the screw a little seat.
I don't know if anyone else will have this issue because I had previously been torturing the drive line just to see where it would fail. The torture was In the form of popping wheelies on a rug where the wheels wouldn't slip as they would on rails. Yea, you read that right, Little Mac was being run hard in reverse and then full forward. The front wheels come off the ground about a half inch. After I stopped laughing, I hung my head in shame, chuckled and then I did it again. I was rewarded by not being able to run at the track. Little Mac got the last laugh.

Now to answer the other question about removing a froze bearing or even a bad bushing. "Grease" is the word.
You need to have a shaft with the diameter of what ever you are trying to remove. i.e. if you have a 3/4 OD bearing with a 1/2 ID, you need a easy fitting 1/2" shaft. The procedure goes like this. Take any kind of grease and fill as much of the bearing ID hole with said grease. Seat the 1/2" shaft as if you are going to insert it into the ID. With a mallet or hammer, start and drive the shaft into the ID bore. Since grease won't compress, something has to give. The result will be the bearing starts to back out of the hole. Once the shaft has neared the bottom of the bore, pull it out and repack with more grease and repeat. And if you have a arbor or hydraulic press available, put down the hammer.
I'm sure you are saying, that's fine and dandy as long as there is not a through hole. Maybe plug the hole by seating a tiny ball bearing or bb. If you can strike the shaft fast and true, grease can not escape fast enough to lose effect. If the inner race is destroyed, remove the rest of the guts and make a shaft for the ID of the outer race.
Other than that, since I can't see the offending bearing, this is about the best I can suggest, short of a dent puller/ slide hammer.

BTW. The 3/4 Barber Truck has been posted on the website. Finished the two prototypes today. Production soon to follow after testing these to the point of destruction.

Thanks again Zach for the great photos. Really nice job.

Marty of FWF

Pontiacguy1
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Pontiacguy1 » Wed May 25, 2016 8:42 am

Maybe I missed this... What type of bearings are you using on your axles? Ball? Drawn-cup needle? Cage Needle?

Marty of FWF
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Marty of FWF » Wed May 25, 2016 6:24 pm

The truck bearings are 608Z shielded ball bearings.

Needle bearings can not take ANY kind of a radial load.
There are plenty of engineering websites that can confirm this. And ball bearing are about in the same boat; however, ball bearings have an inner race which is how we were able to design axle shaft geometry that allows about 3 degrees of radial movement, therefore the truck can flex and NOT bind the bearing.
Whereas the needle bearings being used in most truck must have the shaft straight and hardened because there is no inner race.
Not to say there are needle bearings out there that do have inner races, however they are expensive.
So please read this a couple times very carefully, I'm not knocking anybody's products. I'm just giving solid reasons why we did what we did. I wanted to build a truck that will give years of worry free service and look good doing it.
Marty of FWF

Pontiacguy1
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Pontiacguy1 » Thu May 26, 2016 9:16 am

I think what you meant to say is that needle bearings can not take any type of Axial load. The radial load is the vertical force, which is exactly what they were designed to take.

Ball bearings absolutely CAN take an axial load as well as a radial load. In fact for most radial-type ball bearings, the axial load rating is approximately 30% of the bearing's rated radial load.

So you are running a loose-fit axle inside the inner ring of the bearing?

Marty of FWF
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Marty of FWF » Tue May 31, 2016 9:14 pm

Pontiacguy1,
Thank you so much for clarifying my "radial/axial" hiccup.
It was late, I was tired...excuses, excuses.
Thank you, seriously.
No, we are not running a loose fitting axle in the bearing. We have cut geometry into the axle end which allows movement, while maintaining 100% contact with the inner race throughout almost 3 full degrees of axial movement.
Basically it's a running fit in the bearing id.
Marty of FWF

Marty of FWF
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Marty of FWF » Fri Jun 03, 2016 9:48 pm

Little Mac now has a partner, someone who "has his back".

WJH
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by WJH » Tue Jun 28, 2016 4:18 pm

Nice Lathe! Is it yours or farmed out?

Mike Walsh
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by Mike Walsh » Wed Jun 29, 2016 1:03 pm

Marty of FWF wrote:Little Mac now has a partner, someone who "has his back".
Very nice addition to Little Mac's family.

Will you be considering anything in 1" Scale? A scaled up version of the Little Mac would be just the ticket... Accommodating the battery and controller we discussed.

-Mike

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H&NERY
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Re: Introducing "Little Mac" a 3-1/2" Gauge electric switche

Post by H&NERY » Sun Jul 10, 2016 9:36 am

Very impressed with my "Little Mac" ran it hard on Sarurday at the St.Croix Railroad, after resolving a few minor issues it worked flawlessly, it even made a few laps without an operator. It's nice just to be able to watch your train go around the track. It even double headed with Its brother, the 1st "Little Mac" built. Thank you Marty for a good time on Saturday, glad I came up to the meet.
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