Engines > From Plans
Another Pennsylvania A3 Switcher
crueby:
The main frame came out great! :popcorn: :popcorn:
peatoluser:
yes, the images in the last post are now viewable
Kim:
Great work on the chassis! That's looking very nice. :ThumbsUp: :popcorn: :popcorn:
I also used steel for most of my A3 Switcher build. I used 12L14 when available (round or square rod) and 1018 for rectangular bar. The 12L14 is much easier to machine, but only seems to come in round and square cross sections. I'm in the US, so these are numbers used for steel here. Sorry, I don't know what similar material would be called in South Africa.
Kim
JCvdW:
Thanks Chris and Kim for the kind feedback.
The equivalent to 12L14 in South Africa, is En1A. This is however very scarce, and when available, mostly in round sections.
So I will have to make do with the tougher/harder mild steels available here. With solid carbide milling cutters getting more and more expensive, I decided that indexable carbide insert cutters may be a better option. To be able to use these cutters on my RF-45 clone mill/drill, I thought it would be a good idea to stiffen it up a bit, by fixing the column to the brick wall behind the mill. The idea being not to put any side forces on the column, but to simply add a support that clamps to the column and use the mass of the wall for extra rigidity.
Surprisingly, the extra support resulted in a noticeable increase in vibration! I could use my IPhone as a vibration sensor to do some comparative measurements:
ChatGPT suggested adding extra mass to the base of the machine. Easiest was to add two 40kg bags of swimming pool filter sand:
The sand had the desired effect, and suddenly using the clamp reduces vibrations even further:
The combination of 80kg sand and the clamp resulted in noticeably less vibration.
The new Iscar cutter with indexable inserts works quite well on mild steel. Time will tell if the inserts work out cheaper than solid carbide cutters.
Carrying on with the foot board for the A3 Switcher, the bending jig used for the stairs on the tender, was modified to allow for the two 90 deg bends in the vertical parts:
The foot board after silver soldering. The front bumper was used as a fixture during silver soldering, with extra washers between the foot board and bumper to prevent the bumper from sucking away too much heat.
The front axle box took quite a while to be carved out of a block of steel, but eventually the axle boxes and bushes are all complete.
And now it is finally time to start machining the driving wheels for the engine! Four years ago, I made some wax patterns of the drivers and had them investment casted, as described here: https://www.modelenginemaker.com/index.php?topic=10915.msg252914#msg252914
Kim:
Your vibration reduction looks successful! :ThumbsUp:
As does the foot board! And your cast drivers look really great! I didn't go the casting route, but you sure made a nice set of drivers that way! :) :ThumbsUp: :popcorn: :popcorn:
Kim
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version