G Scale Model Train Forum banner

First Look At Aster/Accrcraft Heavy Makado

5K views 28 replies 12 participants last post by  LarryS 
#1 ·
Here is a First Look at the All New Heavy Mikado. Hope it will be at Diamondhead
 
#5 ·
i recently finished building a modified Aster heavy mikado kit. It turns out that there are a large number of 1/32 USRA heavy mikado parts available on ShapeWays. Most need some modification to fit, but the level of detail is far higher. I bought a firebox (cut off the original Aster firebox), rear frame and proper Cole trailing truck, front pilot, front and rear cylinder covers, steam turret, tender brake cylinder and more. I also scratch built an ashpan, extra piping, wiring conduit detail, tender brake rigging, etc. I am very pleased with the result. I advise anyone with an Aster mikado to check out what is available. Just be aware that the material is extremely hard and can only be worked with carbide tools: to tap holes for screws I drilled out the screw location, soldered in a brass tube, and tapped the tube with conventional taps. Carbide taps are way too fragile. Solder for stainless steel works well.
 
#9 ·
You don't need to upgrade, don't waste your time trying.
We can add attachments, click on the Go Advanced, below and use the Attachment option.
 
#10 ·
I opened the "Go Advanced" link but I did not find an attachment option other than posting icons.

there were two other options;
automatically parse links
automatically embed media

Posting rules still say I cannot post attachments and HTML code is "off" but IMG code is "on"

How should I proceed?
 
#12 ·
I opened the "Go Advanced" link but I did not find an attachment option other than posting icons.

there were two other options;
automatically parse links
automatically embed media

Posting rules still say I cannot post attachments and HTML code is "off" but IMG code is "on"

How should I proceed?
Scroll down past "Additional Options" and you will find "Attach Files", (which includes images.)
 
#11 ·
Sorry Larry, I don't know. I'm not familiar with new members limitations. Other than knowing they were added to confound spammers.
 
#13 ·
It could be that you haven't hit the 10 post minimum yet? Your public profile says only 13 posts since 2008, so if some were before this site was sold to the current owners, who instigated this rule, you may need to post a few more times. Just add some "Hi, improving my post count" messages to a few random threads!
 
#20 ·
The additional cost of the Shapways parts over the kit price is still less than that of the factory assembled locomotive (depending on how many parts you get). However, do not forget the cost of the necessary carbide tools. But it is also possible to get a very well detailed Accucraft (or other make) locomotive for significantly less. I suppose it depends on what you want.
 
#23 ·
General assembly tips

I will post a series of explanations of what was done and then go back and add details to the pictures where needed. It will take a while to get everything written up...

Most of the parts are made of a very hard alloy although the insides of thick sections are much softer than the outsides. But, in general, the parts can only be worked with carbide drills, grinding stones, and cut-off discs. I had to drill and tap the parts for over 50 screws, and using carbide taps was hopeless. After a few attempts I decided to drill the screw holes oversize and solder in brass tubing that could be tapped with steel taps (and drilled if necessary).

Recommended tools:
Bench-top drill press and vise. If the part being drilled moves at all, the small carbide drill bits will break instantly.

Dremel tool with cut-off discs and grinding stones. The edges of cut-off discs can be used to make square corners and several discs stacked together can be used to make slots. The face of a cut-off disc can be used as a sanding disc.

From McMaster Carr or e-bay:
Carbide drill bits, as needed. Most common are 2.15 mm for clearance holes for 2 mm screws and a slightly larger size to fit brass tubing used as inserts for tapping screw holes.

From e-bay:
2 mm tap (not the common M2 x 0.4, but M2 x 0.25 if you plan to use Aster screws).
1.4 mm tap (will fit Aster screws)
2.5 mm tap, will work with 2.6 mm Aster screws
I never did find a 1.7 mm tap so I did not use these Aster screws
2 mm die, (as needed) some parts have sprues that can be threaded to hold the parts in place. Buy 2mm x 0.4 mm nuts to go with the tap.

Stainless steel solder such as Stay-Brite (available from MicroMark and others)

I found the best way to prepare the screw holes was to assemble the parts, drill a 2.15 mm hole through both pieces (if using 2 mm screws), take the assembly apart, enlarge the hole to be threaded to take a brass insert, then drill (if necessary) and tap the insert. Using tubing for the insert rather than a solid rod ensured the tapped hole was automatically centered.
 
#24 ·
rear frame

The rear frame parts fit very tightly and need some grinding to go together. Final assembly is with screws. (I did not put all the screws in the rear crossmember since space was too limited to fit them.) Once assembled, a hole can be drilled through the front and back sections to hold the alcohol burner assembly. Drill the hole so the drill bit passes just above the truck centering spring housing detail in the rear frame crossmember which will put the burners at just the right height. To insert the burner assembly, the frame must be dissembled and then reassembled with the burners in place. Obviously, future attention to the wicks will require removal of the superstructure from the frame. The rear of the cross member must be ground out to provide clearance to connect the alcohol tube. It also must be ground out and modified (with an attaching plate) to fit the tender drawbar.

The equalizer link is part of the truck spring and it needs to be cut off and resembled as a movable part that loosely fits a hole drilled in the spring. If this is not done, the truck swing will be limited by the equalizer link. The spring is the soldered to the horizontal bracket. There is a simulated roller formed as part of the bottom of the horizontal bracket which must be ground off. Any protrusion of the spring locating pin also must be ground off to give a smooth surface for the truck to slide over. A simulated roller can be formed on the trailing truck by soldering a brass rod to the top of the truck in front of the coil spring “dome”, then filing the top of the rod flat to match the top of the “dome”.

The spring/horizontal bracket is attached to the frame by fine wire through the pivot points and a screw through the rear top of the spring. I found that the rear pivot point of the horizontal bracket was too far out and had to be cut off and a tube section soldered on to the shortened arm to get it to ft properly.

The truck is held in by a shouldered pivot screw at the front and a fabricated curved brass tube (screwed to the truck) that goes through the simulated centering spring housing at the rear. Note: the shoulder screw can be made from an ordinary screw and a piece of brass tubing.

The Aster plate and cab floor/support plate are attached to the rear of the frame with screws, the only modification being placing new screw holes in the lower plate to go into the new rear frame. Make sure that the Aster (vertical) rear cab support sits just on the top edge of the new frame (it will have to be filed to fit the frame contour). It is important to get the cab supports in place before fitting the new frame to the Aster chassis since, with the Aster super structure attached, this will be used to align the frame.
 
#25 ·
trailing truck

The general assembly procedure is obvious. Note that the bearing blocks are spring supported inside the truck frame to provide the necessary vertical movement to the wheels. The Aster wheel set fits after drilling out the bearing blocks to take RC ball bearings. I also drilled the spring seats in the bearing blocks and the truck frame deeper to take 1-inch long springs (from McMaster Carr). The holes in the truck above the spring seats were threaded for 2mm screws which held in the bearing blocks. The screws were 2mm x 0.4 screws of the appropriate length bought off of e-bay (the Aster screws were too short) and held in place with Loc-tite.
 
#26 ·
firebox

It is much easier if your locomotive has a black painted boiler because scrapes and scratches can be easily repainted on black. Because I had a green GN locomotive I had to be super careful to preserve the paint. I used a Dremel with a cut-off wheel to slice off the Aster firebox. The Aster sheet metal is stainless steel which is too hard for a razor saw. To avoid damaging the paint from the heat generated, I left a 2 to 3 mm margin and finished the cut by hand filing. I removed all but about 0.5 to 1 mm from the top of the original firebox. More extensive stock removal was required at the junction of the rear of the boiler with the front of the firebox. The Shapeways firebox had to be widened by about 3.5 mm at the front while the width at the rear was perfect. To make the splice at the front, I put the firebox in a vise to squeeze the end pieces so they would line up straight across before soldering in the filler pieces. I cut off the walkway supports on the new fire box and soldered on the Aster supports. A slot was cut in the top of the firebox to form a recess for the support, and the support was rebent to account for the greater thickness of the Shapeways firebox. I needed to make a filler piece at the rear of the firebox under the cab floor area since the Aster floor did not come down far enough. The Aster cab assembly otherwise lined up properly. Four 2 mm screws, placed just above the walkway, were used to hold the firebox in place.
 
#27 ·
Attaching the rear frame to the Aster main frame

This will describe how to attach the new rear frame to the Aster main frame. It is best to carry out this step before cutting off the Aster firebox. Be sure you can complete the frame conversion because it will require modifications to the Aster main frame that are not easily reversed.

Begin by making sure that the Aster cab floor and floor support plate is properly positioned on the rear frame. A shim is probably required at the front of the floor support where it rests on the frame so that the floor is level with the frame. In my case I needed a shim plate of 0.032 inch brass. But this may vary. Next, install the Aster alcohol firebox on the bottom of the boiler (it will be necessary to cut off the extension that supports the front of the burner assembly). Assemble the boiler into the Aster superstructure and fasten both the rear of the boiler and the superstructure to the cab floor. The Aster alcohol fire box will rest on the rear frame crossmember, make sure that this does not prevent the proper positioning of the cab floor.

The Aster rear frame is attached to the main frame with 6 screws on each side. The Shapeways rear frame only has provision for 4 screws. Shorten the Aster main frame by cutting off the rear set of 2 screw holes, leaving only 4 holes. The 4 screw holes of the new rear frame do not line up with the 4 Aster screw holes. Find one Shapeways screw hole that lines up with an Aster screw hole and puts the rear frame in the correct position. To get the new frame to fit it will probably be necessary to file a clearance notch in the Aster frame for the brake hanger bracket that is part of the Shapeways frame. If the Shapeways firebox is already installed, the Aster brake hanger tab will have to be cut off as well. In my case the screw hole I used was the lower front Shapeways hole. Thread this hole in the Shapeways frame and attach the rear frame to the Aster main frame using the reference screw on each side. Note that the new frame is slightly narrower than the Aster frame and a shim of about 0.016 in thick will be needed on each side. Put the assembly on a flat surface (without any wheels installed) and make sure the walkways on the Aster superstructure are parallel with the main frame and the rear of the Shapeways frame is parallel with everything as well. If not, find a different screw hole to use as the “reference” hole.

Next dissemble the Aster main frame and the Shapeways frame. Fill the pilot screw holes in the Shapeways frame with brass wire and solder to make it easier to drill off-center holes. Attach a Shapeways frame section to an Aster main frame section with the reference screw. Then drill out the remaining screw hole locations in the Shapeways frame using the holes in the Aster frame as a drill guide. Dissemble the parts, drill the Shapeways holes larger for the brass tube used to prepare the holes for threading and finish remainder of the Shipways screw holes. Cut/file the Aster frame to the correct contour; the Shapeways designer can be contacted through Shapeways and he can provide some very detailed drawings. Alternatively, look up the information on the web. Before reassembling the frame pieces, drill and tap (as needed) the truck mounting point on the Shapeways crossmember and work out an attachment arrangement to fit the trailing truck (probably using a brass tube sleeve, various washers, and a screw). At this time, the Shapeways crossmember can also be notched for the feed water tubing as the tubing will eventually be run up under the (future) ashpan coming out next to the Aster alcohol internal firebox. Although it might be better to wait until the ashpan is constructed to do this…

In any case, assemble the frame with wheels and trailing truck and make sure everything is aligned as it should be. Fix any problems before making any more modifications. I found that the trailing truck wheels were almost exactly in the center of their vertical travel at this point in my build.
 
#28 ·
Ashpan:

I made an ashpan out of 0.032 inch sheet brass to fill the space between the fire box and rear frame. It is important to keep the slanted hopper sides below the shelf on the rear frame crossmember where the Aster alcohol firebox sits so that the ashpan will not interfere with the fire box. The bottom of the ashpan was left open to allow air to the alcohol burners. The front of the ashpan follows the slope of the frame and this is important so that the boiler feed water pipes can be run up under the front of the ashpan and out from under the Aster alcohol firebox on each side. The ashpan is held in place by two screws on each side, one is a front frame cross member screw, the other is drilled through the frame behind the trailing truck wheel. To help shape the ashpan pieces, I made cardboard templates, but I ended up making two brass ashpans anyway before I was happy with the fit.
 
#29 ·
ashpan

I made an ashpan out of 0.032 inch sheet brass to fill the space between the fire box and rear frame. It is important to keep the slanted hopper sides below the shelf on the rear frame crossmember where the Aster alcohol firebox sits so that the ashpan will not interfere with the fire box. The bottom of the ashpan was left open to allow air to the alcohol burners. The front of the ashpan follows the slope of the frame and this is important so that the boiler feed water pipes can be run up under the front of the ashpan and out from under the Aster alcohol firebox on each side. The ashpan is held in place by two screws on each side, one is a front frame cross member screw, the other is drilled through the frame behind the trailing truck wheel. To help shape the ashpan pieces, I made carboard templates, but I ended up making two brass ashpans anyway before I was happy with the fit.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top