|
Post by ramkitty on Oct 14, 2010 21:20:18 GMT -5
No pictures yet though I should, the red paint and the polished wheels look really slick. I bought a 7x12 lathe with dro handles and a taig milling attachment for 480CDN which is pretty good I think. It had a bunch of tooling too and the guy had done some of the standard tweaks already. I defiantly need to get one of the tailstock lever mod done and I am not keen on how the compound is adjusted. I also cut 2 bushings for the tender axles and cut one axle to length. I will try to remember the camera tomorrow so I can take a photo of the 9 tender wheels and the other stock I have cut waiting for action. How do I accurately turn a spindle length shoulder while maintaining a square face. Do I use one of the cutters with a 30 and 60 deg angle and set the 30 perpendicular to the spindle axis? EDIT: Took a day off work.. at work. I finished 6 of 8 axle bushings, Squared to length the Jboxes, front/rear end sills and bolsters but I forgot I ordered 3/8th side sills so I need to take off 1/8th off. I also squared off the column members one more axle (2 left) and marked the bushing hole on the Jboxes. I feel like I got a lot done as I have laid it out like it is being built. I am really liking the little lathe it is way more accurate than the combo trash that my work has I guess I will find out shortly if it is suitable for milling or will I bust out a grand for a mini mill too; the lathe with the dro dials is able to cut withing .0005 after taking off several passes for a total cut over .1 I am quite pleased. I am not super thrilled with the compound angle adjustment but I guess its not really used to often and I was having difficulties with the tailstock but I figured out how to get it to set accurately and repeatably. Pictures to come, cant find the work camera so I will have to sneak the home one past the boss.
|
|
|
Post by phutcheson on Oct 19, 2010 11:44:46 GMT -5
Ken ...
Thanks for the clarification ... now I remember that you're making the 1.5". At first I was wondering why you are using O-rings instead of metal rings. Then I looked up the New Shay build I found there he stays with the O-rings for the larger version! I guess it doesn't matter. So far my O-rings seem to be fine ... a nice fit, we'll see more when I get ready for the air-run. I do have to be careful when installing them they can be damage very easily. Especially on the edge of the cylinder.
ramkitty ...
Sounds like you are making some real progress. Your 7x12 lathe should work great for all turning. I really don't quite understand your question, so I will let someone else answer it.
Pictures and more pictures ... hope to see lots of them.
I'm nearly finished with the Tie Plate so I'll be working on the Guide Yokes in a day or so.
Pat H.
|
|
|
Post by ramkitty on Oct 19, 2010 16:00:38 GMT -5
I am unsure how to lathe the shoulder on the axles to a precise length maintaining the square. I know how to face to a precise length but maintaining square shoulders while reducing the diamater of the bar for .3120 +.0005 for the wheel journal is harder.
The mini lathe site has some info but I want to turn the shoulder to within .5 thou how do I maintain the tight tollerance. Do I use the cutting tool square to the work or turn down the diamater to approximate length then face down to precise width while being careful not too reduce the diamater too much?
|
|
|
Post by kvom on Nov 12, 2010 16:02:14 GMT -5
I am unsure how to lathe the shoulder on the axles to a precise length maintaining the square. I know how to face to a precise length but maintaining square shoulders while reducing the diamater of the bar for .3120 +.0005 for the wheel journal is harder. The mini lathe site has some info but I want to turn the shoulder to within .5 thou how do I maintain the tight tollerance. Do I use the cutting tool square to the work or turn down the diamater to approximate length then face down to precise width while being careful not too reduce the diamater too much? Kozo shows how the corner is undercut (Fig. 2-17) on p11. You might consider undercutting the corner using a grooving/parting tool. Keeping the tool square to the face, maintain the width (a bed stop is useful here if you don't have a DRO). With the diameter a few thousands larger than spec, undercut the corner using the compound. Now you can finish the diameter, and by stopping at the start of the undercut you won't alter the width. Assuming that you have reamed the tender wheels (.3125 = 5/16), and you are going to fix them with loctite, then you want a good sliding fit. You may find it easier to attain this by taking off the last few tenths with abrasive strips rather than machining.
|
|
|
Post by phutcheson on Nov 25, 2010 3:16:42 GMT -5
Updated my website to add the Guide Yokes Assembly. That was fun ... very close tolerances for the assembly .0025"!
phutcheson.net/images/A3 Switcher/Pistons Crossheads Guide Yokes/Guide Yoke2875 resized.jpg[/img] See website for a few more pictures. Also I decided to use Loctite on the Piston Rod and Pin ... followed Kozos method. Working on the Valve Gears ... Getting closer and closer for the big day ... running on air! Maybe by year end ? Pat H.[/color]
|
|
|
Post by Harlock on Nov 26, 2010 0:52:43 GMT -5
Cool pat. Mucho progress since bitter creek.
We've got another engine we're refurbing now, so the A3 parts continue to sit on a shelf.
|
|
|
Post by GregMiller on Nov 26, 2010 10:49:21 GMT -5
Beautiful work Pat! You have certainly crossed a major milestone. I was looking at the pictures of your Tee and it appears that you followed Kozo's instructions for machining the exhaust passage and the steam pipe. I was wondering why the 4-jaw chuck would be used for the exhaust passage vs using the mill to drill and tap the hole. Also, why not start with a 5/16 round, thread it for 5/16 -24 and SS it to a shorter Tee top? Others can chime in too I just find that getting everything aligned and true in a 4-jaw can be finicky at times. If there is a reason why the lathe should be used for these operations, I'll will, but I'd like to understand why. Thanks, Greg
|
|
|
Post by phutcheson on Nov 28, 2010 13:48:48 GMT -5
Thanks guys ....
Harlock,
Yes ... I have been able to spend some quality time in the shop. Hope to continue till the end of this year. Haven't seen any Bitter Creek pictures yet ... plan on posting any? Looking forward to some great stuff...
Not working on your A3 again?!! ???Must be something special ... can you tell us what either here or another forum.
Greg Miller,
Yes, I usually follow Kozos methods ... but not always.
I did follow his method for the tee because as I understand it ... using the lathe there is a better chance for drill passages to be true and when done together in one chucking hole(s), threads and the recessed hole will all be concentric. Additionally and probably most important ... the two faces must be parallel to each other and the side frames ... no gaps. With a mill that is much harder to obtain ... well, at least for those that are not machinist. Which I'm not and will never be. Take a look on page 25 paragraph 4.3.
For the threaded hole ... looks like the mill would be okay. Short distance, so the passage would terminate at the correct location and be fairly straight.
As far as the machining a 5/16" plug then SS to main body ... that would require a lot of addition steps ... machine the plug for the threads, threading, drill the passage hole then drill the recessed hole. Next drill hole for the plug, clean, SS, more cleaning, then finish the passage hole. On the other hand once the tee is mounted on the lathe all machine operations can be done in one chucking.
So I really think that depending on the need for accurate machining, the machine capabilities, tools available and your skill level... those things would dictate your machining methods. I believe that Kozo is aiming at the beginner level ... like me.
I also have trouble getting the 4-jaw lined up ... but I keep at it until done, even if I have quit for a while come back later. The more I do ... easier it gets.
Hope this helps and looking to read more about your progress....!
Pat H.
|
|
|
Post by Harlock on Nov 28, 2010 14:25:21 GMT -5
Pat, Bitter creek photo essay will be published in the May / June issue of Live Steam next year, should be a cover article. We're currently re-finishing a MEG Steam 'Wendy' 4" scale 7.5" gauge 0-4-0 from the chassis/boiler on up. It's a working engine that just needs new plumbing and new cab / tank, cosmetics, and re-machined worn hackworth valve gear slides. It was not taken care of by the previous two owners and is getting a full makeover and restoration. When finished it is an engine you can sit in upright and run it comfortably, a daily runner for fun.
|
|
|
Post by GregMiller on Nov 28, 2010 22:22:18 GMT -5
Pat,
I too am a novice, so I'll pay attention to Kozo's recommendations and instructions. Thanks for the reference on page 25, that was a help.
I am looking forward to getting back to work on my A3a. I was getting organized over this past weekend... it has been since the middle of July since I have spent time on the A3a. I have had shop time, just on other projects.
I am glad that you take time to post pictures on here as well as your website. I know that I enjoy looking at them as well as using them for reference.
Greg
|
|
|
Post by phutcheson on Dec 7, 2010 2:10:37 GMT -5
Harlock ...
Congratulations on your cover photos essay... better check to be sure my subscription is up to date.
Where do find the fixer uppers ... I guess it must be fun to rebuild. Most likely is much faster!
Greg Miller ...
That is a long time ... you must have been in real pain not being able to work on the A3 but at least you have been in the shop.
Glad your back and hope to see more progress ... on the A3 that is!!
Pat H.
|
|
|
Post by kenrinc on Dec 7, 2010 18:35:13 GMT -5
Pat,
Nice to see were at the same spot (accept my parts are bigger!). I'm fitting the crosshead guides now and am amazed that Kozo does not go into any detail here considering that the guides must be parallel to the piston rod in both planes. He doesn't even udder a word about it. Assumes you machine everything as shown it will line up, well...... maybe. I've made a jig to allow me to line up everything as I'm putting it together which helps. Loctite here too!! At least when I have them in final position.
Greg, you can do whatever you want for the tee. As was mentioned the only critical parts are the distances between the frames. It should be the same distance as the outside surfaces of the frames but if it's short by a few thou that's ok as the gasket compound will more than likely take care of the difference. If not you can make traditional gaskets. I actually had to make my tee differently because in 1.5" scale you really cannot get enough heat into the iron fast enough to silver solder it. I tried, twice. I could get it near but not at the melt temp. I finally I ended up machining off the middle section and removing the square center. This reduced the amount of "heatsink" the entire assembly was acting as and allowed me to get the remaining piece up to temp and silver solder two pieces of copper pipe to accept the dry pipe and exhaust nozzle respectively. Will try to post pics later.
Ken
|
|
|
Post by kenrinc on Dec 8, 2010 1:33:50 GMT -5
Here is the modified tee I made for my 1.5" scale version of the A3: Ken
|
|
|
Post by kvom on Dec 8, 2010 7:57:22 GMT -5
Doing it that way, there is no real need to SS the vertical piece; just machine tee from bar. And shorter holes to drill. I'll keep an eye on your build for when it's time to do mine. Why did you SS the blower pipe rather than thread as per the plan?
I see from the plans that the tee width is 1/16" greater than the outside width of the frame, leaving 1/32 on each side for adjustment.
|
|
|
Post by kenrinc on Dec 8, 2010 13:16:47 GMT -5
I could have just as well threaded them but I don't have the needed NPT taps and I felt it was easier just to cutoff the thread on one end of the pipe, bore the holes bigger for slip fit and ss. Remember, I had already built the tee per Kozo's instructions. It's only when I couldn't get the unit hot enough to ss that I had to figure out another way. Doesn't matter where the threads are.
The length of the tee is whatever the outside frame dimension is. Remember in 1.5" you adjust based on track gauge. Since the frame is not doubled in 1.5" scale you need to adjust to suit. Mine is about .002 short to allow for liquid gasket. The reality is that once they are bolted down they may very well be exactly right.
Ken
|
|