Stephenson's Rocket--Working Model

[Peter Twissell]

Belated happy Birthday Brian!
She's really looking the part and the engines run nicely. They appear to be running almost synchronised in the video. I assume they will be timed 90 degrees apart.

 

[bigal2749]

Happy Birthday

Looks like you made your own birthday present

 

[Brian Rupnow]

Peter---You are correct.
Now I get to see whether or not I'd make a wheelright. This piece is 5 1/2" outside diameter x 3 1/2" inside diameter x 1.8" long. It is the only piece that size in all of Barrie, and I got it for $21.50 there is sufficient material there to make two drive-wheels, and I will try and make a detailed post as the drive wheel fabrication progresses.

 

[awake]

Happy birthday!

 

[Brian Rupnow]

I've looked at a few different ways of fabricating these large drive wheels. I really liked whats shown here, because the round holes in the hub locate the spokes radially, and the sides of the groove in which the spokes set keep the spokes all parallel. The spokes could be loctited into the holes in the hub, and tig welded to the outer rim. The only problem is that every one of the 24 spokes would have to be set up in the 4 jaw chuck, indicated, and then turned down to 0.150" diameter in order to work. I don't mind a bit of 4 jaw set-up, but doing it repeatedly 24 times is a bit too much.

 

[Brian Rupnow]

My current idea is a bit more exotic.--Has more parts, but is "easier?" to fabricate because I don't have to turn the ends of the square spokes to fit into round holes. I have reduced the number of spokes from 12 to 10, and they are all located by the machined red hub (the red hub is shown both "in place" and copied to the right hand side of the assembly so you can see what it looks like by itself). The red hub, although it looks complex, is all just basic rotary table work using a 3/16" end-mill cutting 3/16" deep. The spokes can lay in their appropriate slots and be Loctited in place, and the outer ends of the spokes can be tig welded to the outer rim.

 

[Brian Rupnow]

Regardless of what I do with the inner hub and spokes, the outer rim will not change. Next step will be to mount the material for the outer rim on my lathe and machine two outer rims from it. Because of the very real possibility of heat distortion from welding changing things a bit, I will make the rim about 1/16" greater than the drawing calls for, and about 1/16" wider than the drawing calls for. This will allow me to make clean up passes after all of the welding is completed.

 

[awake]

Brian, the first approach would be the ideal use case for a square collet - if you happen to have a collet chuck. (I don't ... it is one of my wish-list items!)

 

[Brian Rupnow]

This hub seems to be the most complex part of the drive wheel assemblies. I was going to begin by machining the outer rims first, but I've had a change of heart, and this is what I will be making today.

 

[Brian Rupnow]

Here we have the hub, reamed to a 0.75" bore, and stock 1.25" o.d. mounted in the rotary table, and a slot 0.188" deep cut with a 3/16" endmill. One picture shows the cut slot, the second picture shows a piece of the 3/16" square key material tapped into place for a trial fit. I have found out two things. #1---My 3/16" endmill is painfully dull, and #2 that my shoulder wants to quit about half way thru taking 0.005" depth of cut. Next trick will be to index the rotary table 36 degrees and do it over again.

 

[awake]

Brian, are you saying that you can only take .005" DOC at a time? Ouch - that's definitely going to take a while.

 

[Brian Rupnow]

Things got a lot easier when I switched to a carbide endmill and was able to take 0.010" depth of cut. This is the hub which has not been cut to finished length yet, but has one spoke setting in place to show how it's going to work.

 

[awake]

.010" at a time still sounds painful, but glad you got it done!

 

[Brian Rupnow]

These shots show the two piece center hub and one spoke. I'm happy with it so far. It will require a bit of touch up with a file before final assembly, but so far--so good.

 

[Brian Rupnow]

Things are going to stop for a while now. My lathe quit working last night about 6:00 o'clock. I was half way thru a cut, turning at 400 rpm with a 0.015" depth of cut , in automatic feed mode. The lathe just stopped. No grind, no clunk, just stopped dead as if the power supply had died. I have checked the fuses and that is really all I can check. I'm afraid I may have to take my lathe to BusyBee in Toronto and have their technicians fix whatever went wrong.

 

[Richard Hed]

Things are going to stop for a while now. My lathe quit working last night about 6:00 o'clock. I was half way thru a cut, turning at 400 rpm with a 0.015" depth of cut , in automatic feed mode. The lathe just stopped. No grind, no clunk, just stopped dead as if the power supply had died. I have checked the fuses and that is really all I can check. I'm afraid I may have to take my lathe to BusyBee in Toronto and have their technicians fix whatever went wrong.

Certainly you could check a few more things before having someone else look at it. Check the power outlet (socket)--some times they fry, along with the power cord and plug. Also check the wire going into the motor to see if it is frayed or something and if you can, check inside the motor to see the wire connections--sometimes they wiggle loose. Also check the power switch if it is checkable.

 

[werowance]

ill just say my lathe got a chip inside the motors electric box on the side of the motor which had screw terminals to mount the wires (for 220 or 110 hookups). no noise, did not trip the breaker but it did melt the screw terminal and the machine was dead. 3 wire nuts and some black tape and the screw terminal was eliminated and machine was back in business.

I can only hope its this simple for your machine.

 

[awake]

Richard's comment reminded me of the time we lost a really nice hand mixer. It stopped working, according to my wife ... I took a quick look at it, but other than verifying that it didn't work, I didn't have time to dig into it to any great degree, so we threw out the old mixer and bought a new mixer - not as nice as the old one, which had been a gift. But then the new mixer didn't work ... at which point I realized that the GFCI that controlled all of the kitchen counter outlets had tripped!

It still makes me feel sick that I threw out what may have been a perfectly good mixer!

 

[Richard Hed]

Richard's comment reminded me of the time we lost a really nice hand mixer. It stopped working, according to my wife ... I took a quick look at it, but other than verifying that it didn't work, I didn't have time to dig into it to any great degree, so we threw out the old mixer and bought a new mixer - not as nice as the old one, which had been a gift. But then the new mixer didn't work ... at which point I realized that the GFCI that controlled all of the kitchen counter outlets had tripped!

It still makes me feel sick that I threw out what may have been a perfectly good mixer!

OMG, LOL, been there, done that!

 

[stevehuckss396]

Gees brian isn't there someone you can call that can fix it on site? Seems like alot of work to haul it somewhere. I have a guy on speed dial.