Search found 81 matches

by FinePine
Sun Sep 30, 2012 4:00 pm
Forum: Car & Semi-Truck Construction
Topic: Turning Wheels on a Mini Lathe.
Replies: 73
Views: 10574

Re: Turning Wheels on a Mini Lathe.

So, the 7x mini-lathe chuck is held on by screws and nuts to a faceplate on the spindle, but once you get that off, the taper is exposed.

http://www.mini-lathe.com/Mini_lathe/Fe ... tm#Spindle" target="_blank

Great websites available for these lathes, I must say.
by FinePine
Fri Sep 28, 2012 1:21 pm
Forum: Car & Semi-Truck Construction
Topic: Turning Wheels on a Mini Lathe.
Replies: 73
Views: 10574

Re: Turning Wheels on a Mini Lathe.

Stan Pope wrote:Neat idea! Thanks!
The lesson on the importance and difficulty of maintaining concentricity may suffer, however, since your students won't have to go through the effort of preparing the mandrel for their own use.
by FinePine
Fri Sep 28, 2012 1:16 pm
Forum: Car & Semi-Truck Construction
Topic: Turning Wheels on a Mini Lathe.
Replies: 73
Views: 10574

Re: Turning Wheels on a Mini Lathe.

How much effort is involved in removing the spindle, etc.? Could you quantify (put a number on) just how good "very good" repeatability is? The Unimat 3 does not have a Morse taper, just a slip fit with a centralizing chamfer. Repeatibility was good enough that I couldn't measure it with a regular ...
by FinePine
Mon Sep 17, 2012 8:34 pm
Forum: Car & Semi-Truck Construction
Topic: Turning Wheels on a Mini Lathe.
Replies: 73
Views: 10574

Re: Turning Wheels on a Mini Lathe.

Hi Stan. If your chuck doesn't give you the chucking repeatability you need, consider eliminating the chuck! The mini-lathe spindle has a #3 Morse taper in it, no? If so, you may consider making a wheel mandrel out of a Morse taper blank that fits directly into the spindle bore, eliminating the need...
by FinePine
Thu Sep 23, 2010 10:04 am
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - "How To Guide"
Replies: 188
Views: 69863

Re: Rail Riding - "How To Guide"

I'd be interested to know: if you push the top of the wheel in to match the angle of the axle, does it stay there? And if you then roll the car a bit, what happens?
by FinePine
Thu Sep 23, 2010 9:12 am
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - "How To Guide"
Replies: 188
Views: 69863

Re: Rail Riding - "How To Guide"

Thanks for the link. Later in the same thread, Stan's casual observations match my own, which is that the wheel tilts up to match the angle of the axle. There are three moments acting on the wheel that determine whether it lies "tread flat" or is angled (car at rest on a level surface). If you look ...
by FinePine
Wed Sep 22, 2010 4:26 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - "How To Guide"
Replies: 188
Views: 69863

Re: Rail Riding - "How To Guide"

FinePine - are you taking into consideration that 1.9 degrees of the canted axle will be taken up in the "bore slop" such that 2.5 degrees of axle cant will provide 0.6 degrees of wheel cant? I haven't observed a loss of camber. If the contact point of the wheel to the track is vertically between t...
by FinePine
Tue Sep 21, 2010 4:25 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - "How To Guide"
Replies: 188
Views: 69863

Re: Rail Riding - "How To Guide"

To get a "level" car that has negative rear camber and positive front camber, the rear holes need to be a bit lower than the front to account for the angles of the axles. But all this "height of axle hole" talk is dependent on the shape of the bottom of the car. But even if it is flat, and it slopes...
by FinePine
Fri Aug 13, 2010 2:02 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - "How To Guide"
Replies: 188
Views: 69863

Re: Rail Riding - "How To Guide"

Thank you for the images. 2D views are the best way to show things, I think. I'll also have -2.5 degree camber in the rear, and +3.5 in the front. This depends on if the front of the car is narrowed to bring the following rear wheel out further from the center rail. Well, what I'm trying to do is de...
by FinePine
Wed Aug 11, 2010 4:20 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - "How To Guide"
Replies: 188
Views: 69863

Re: Rail Riding - "How To Guide"

I'm approaching rail riding from the viewpoint of the wheels relative to the track instead of the wheels relative to the body, and this brings up several questions. What I mean is that I'm designing a car in 3D CAD software, starting with a section of flat track, then placing the wheels in the locat...
by FinePine
Wed Jul 28, 2010 4:12 pm
Forum: Car & Semi-Truck Construction
Topic: Hub to axle clearance, lubes, etc.
Replies: 4
Views: 896

Re: Hub to axle clearance, lubes, etc.

Thanks for the links.

I think this is one of the threads I was reading:

I have a nearly full bottle of NyOil, so would prefer not to buy Krytox, but if it is really the safe bet, I will. Hate messing with graphite.
by FinePine
Wed Jul 28, 2010 12:13 pm
Forum: Car & Semi-Truck Construction
Topic: Hub to axle clearance, lubes, etc.
Replies: 4
Views: 896

Hub to axle clearance, lubes, etc.

Hello all, It's time again for my company's PWD, but this year they have changed the derby class rules significantly to prevent me from doing my thing with the lathe. No wheel or axle mods other than a tread polish and axle burr removal and polish will be allowed. Despite this attempt to make the ca...
by FinePine
Tue Jul 27, 2010 9:58 am
Forum: Car & Semi-Truck Construction
Topic: Teflon Theory v. Practice
Replies: 20
Views: 7524

Re: Teflon Theory v. Practice

A good test for Teflon would be to ream out a wheel bore and sleeve it with a Teflon liner, and run that on a dry axle. Then you could test the low CoF of Teflon seperately from the issue of the powder form.
by FinePine
Tue Jan 12, 2010 5:28 pm
Forum: Car & Semi-Truck Construction
Topic: New Axle sighting? Updated with Pics
Replies: 26
Views: 4499

Re: New Axle sighting? Updated with Pics

We've used the Pinewood Extreme kits here at work for the last couple of years. The wheels in these kits appear to be made from old BSA molds, with no sidewall lettering, recessed hubs, and with the "S.A." in "OFFICIAL B.S.A." machined off. The axles in the kit are the same as shown in the original ...
by FinePine
Thu Oct 29, 2009 11:26 am
Forum: Car & Semi-Truck Construction
Topic: Moving a rear axle forward or aft
Replies: 13
Views: 1033

Re: Moving a rear axle forward or aft

During a curved section of the track, the forward rear wheel will tend to lose contact with the track. With a rear weighted car, I expect that the car would diagonally tilt to maintain/restore contact on both rear wheels. If your car is a 4-wheeler, it will become a 3-wheeler. If it is a 3-wheeler, ...