Re: Boxpok driver model preview
Impressive work. However, like Gary, I would enter a cation re. the use of GIMRA finescale standards. Sure, the wheels look a lot better, of course US engines don't have 'splashers' to disguise the overscale flanges tires of the usual standards. Depends I guess on what you want - the best looking model or a loco that can run on tracks go through points on any G1 track, anywhere. Art Walker, Guildford, England. - Original Message - From: XXYZ [EMAIL PROTECTED] To: Multiple recipients of sslivesteam [EMAIL PROTECTED] Sent: Monday, October 28, 2002 12:11 AM Subject: Boxpok driver model preview Hi, If anyone in interested, I uploaded some jpegs to http://moosedog.home.mindspring.com/. The pics are three views of a 3d CAD model of the Boxpok driver that I am modeling for one of my G1 live steam projects. The driver shown is a 72 inch, #1 axle, for a 4-8-4 (Northern). The wheel face, spoke holes, rim and hub are all scaled from the prototype. The tire profile and thickness are modeled to G1MRA IF standards (sprung). I still need to decide on how (or if) to add the undercuts inside of the spoke holes that don't go all the way through (as with the prototype). This will make it more difficult to produce the casting but it may be necessary for the wheel to look right. My intention is to produce a set of 74 dia. (2.3125) wheels for myself and for others that may be interested (it's going to be a while before I get that far as I need to do a lot of research on casting, I may have these cast professionally in stainless). I still need to resize the model from 72 to 74 and re-size the spoke holes to accommodate. I used the 72 driver as the basis for the model as I have a prototype that I can photograph and measure nearby. It appears from the references, that I have, that there are several styles of Boxpok drivers with spokes that have slightly different visual weights. So I will need to reconcile the look of the model and the photos as a change wheel sizes. Most of the photos that I have show a lighter (larger holes) looking wheel than what I have modeled. I have also included a jpeg of the American project that I am working on as well but is currently on the back burner. The weather has been nice for the past few weeks so I went to the CRRM the get some measurements that I needed to complete the Boxpok driver model. The half cylinder casting and the crosshead are placeholders and will be redesigned and the frame needs to be lengthened slightly. I am debating on if it would be worth it (or to difficult for the advanced beginner) to spring and equalize the main drivers. This would mean machining axle boxes instead of round bushings and some other parts. I am currently thinking (keep it simple, like with the Dee). I think that the cylinders are going to be built up by silver soldering machined sub-parts together which will bring the difficulty up already. Any comments would be appreciated. Ken Vogel
Re: Boxpok driver model preview
I would definitely spring the drivers. Even in gauge 1 the engine will run much happier with springing. Equalizing is something else again. It's complex and fiddly (especially if you equalize across the chassis as well as on each side) and won't get you much for your trouble compared to the gains from simple springing. Also, you cannot get the exact prototypical look using leaf springs. If you copy the full size exactly, the springs are too stiff. To correct that you can go undersize with the leaves and pack the stack. But then you've lost the look. Dummy leaf springs with concealed coils doing the actual work are a pretty good compromise. If you want something good for beginners, I would not use SS for the drivers. It can be too frustrating to machine. Also, if I hadn't done quite a bit of casting I would stay with aluminum and zinc (or other low temp white metals). These, however, need a tire shrunken on and so another job. Only if I wanted a really big project would I try brass and cast iron rather than have them commercially done. Victor Lacy - Original Message - From: XXYZ [EMAIL PROTECTED] To: Multiple recipients of sslivesteam [EMAIL PROTECTED] Sent: Sunday, October 27, 2002 6:11 PM Subject: Boxpok driver model preview snip I am debating on if it would be worth it (or to difficult for the advanced beginner) to spring and equalize the main drivers. This would mean machining axle boxes instead of round bushings and some other parts. I am currently thinking (keep it simple, like with the Dee). snip My intention is to produce a set of 74 dia. (2.3125) wheels for myself and for others that may be interested (it's going to be a while before I get that far as I need to do a lot of research on casting, I may have these cast professionally in stainless). Ken Vogel
RE: Boxpok driver model preview other questions
Art, Gary Thanks, for the info on the fine standard relating to track. I used the IF wheel profile on the model for illustration purposes, the I profile looked kind of vulgar on the CAD model (like N-scale wheels). I do intend on having enough material available for machining. But, this raises a few questions as I haven't had any experiance with the standards. I would like to know what track standard is generally used in the states, especially club layouts and steam-up meet display layouts. Do U.S. modelers use G1MRA or is there another (NMRA) standard? What wheel profile is Aster using? It is hard to tell from the catalog photos and it isn't mentioned in the text. If they are using the G1MRA I profile, It doesn't look nearly as bad as I thought it would. It's sometimes hard to tell when modeled in CAD how proportionally good or bad things will look. Could the flange depth be reduced to 1.5mm on a G1MRA I wheel profile without any adverse effects? Ken -Original Message- From: [EMAIL PROTECTED] [mailto:sslivesteam;colegroup.com]On Behalf Of Gary Broeder Sent: Sunday, October 27, 2002 10:52 PM To: Multiple recipients of sslivesteam Subject: Re: Boxpok driver model preview Ken, and others, Be advised that if you go with G1MRA 1F wheel profile the trackwork will need to be of fine standard as well. This is particularly important if there is any intention of selling them in the modeling market. It might be worth building in a bit of extra material on the backside for those using non-1F standards allowing them to machine a wider tread. A wheel, if based on 1F standards, requires that turnout guardrails are set at 1.75 mm vs 3.0 mm on the non-fine standards. The narrower the tread the more of the wheel drops at the half point of the frog. The 1F standard also has is less wheelset to track gauge side slop, this being .75 mm total for 1F and 2 mm total for non 1F standard. Gary Broeder
RE: Boxpok driver model preview American
Victor, Thanks for the reply. I think equalizing the American would be rather simple. It only requires a set of equalizers between the driver axles (a simple see-saw). I would use coil springs hidden behind the frame if space allows and fake the leaf spring, only using it as the beam for equalizing. Cast iron would be the material of choice for the American drivers. I may post a jpeg of these later. Thanks Ken -Original Message- From: [EMAIL PROTECTED] [mailto:sslivesteam;colegroup.com]On Behalf Of Jeanne Baer Sent: Monday, October 28, 2002 9:05 AM To: Multiple recipients of sslivesteam Subject: Re: Boxpok driver model preview I would definitely spring the drivers. Even in gauge 1 the engine will run much happier with springing. Equalizing is something else again. It's complex and fiddly (especially if you equalize across the chassis as well as on each side) and won't get you much for your trouble compared to the gains from simple springing. Also, you cannot get the exact prototypical look using leaf springs. If you copy the full size exactly, the springs are too stiff. To correct that you can go undersize with the leaves and pack the stack. But then you've lost the look. Dummy leaf springs with concealed coils doing the actual work are a pretty good compromise. If you want something good for beginners, I would not use SS for the drivers. It can be too frustrating to machine. Also, if I hadn't done quite a bit of casting I would stay with aluminum and zinc (or other low temp white metals). These, however, need a tire shrunken on and so another job. Only if I wanted a really big project would I try brass and cast iron rather than have them commercially done. Victor Lacy - Original Message - From: XXYZ [EMAIL PROTECTED] To: Multiple recipients of sslivesteam [EMAIL PROTECTED] Sent: Sunday, October 27, 2002 6:11 PM Subject: Boxpok driver model preview snip I am debating on if it would be worth it (or to difficult for the advanced beginner) to spring and equalize the main drivers. This would mean machining axle boxes instead of round bushings and some other parts. I am currently thinking (keep it simple, like with the Dee). snip My intention is to produce a set of 74 dia. (2.3125) wheels for myself and for others that may be interested (it's going to be a while before I get that far as I need to do a lot of research on casting, I may have these cast professionally in stainless). Ken Vogel
RE: Boxpok driver model preview other questions
At 12:22 PM 10/28/02 -0700, you wrote: I would like to know what track standard is generally used in the states, especially club layouts and steam-up meet display layouts. Do U.S. modelers use G1MRA or is there another (NMRA) standard? The aftermarket wheel makers in the U.S. have developed profiles with superb operating charateristics. If I were doing it I would emulate one of those. Regards, Harry
Suspension [was; Re: Boxpok driver model preview]
This is something I've been curious about for a while now. Why are real springs too strong? Are our locos not heavy enough or is it a problem with the volume of metal used in the springs? Could real leaves be made with hollow sections? I know it'd be a lot of work but this is just for the sake of understanding... Is there not some lighter metal that could be used, or do they get too malleable at the 'correct' flex range so that they'd be easily bent? Curious foxes want to know! Trot, the fox who's not a rivit counter, really..! On Mon, 28 Oct 2002, Jeanne Baer wrote: I would definitely spring the drivers. Even in gauge 1 the engine will run much happier with springing. Equalizing is something else again. It's complex and fiddly (especially if you equalize across the chassis as well as on each side) and won't get you much for your trouble compared to the gains from simple springing. Also, you cannot get the exact prototypical look using leaf springs. If you copy the full size exactly, the springs are too stiff. To correct that you can go undersize with the leaves and pack the stack. But then you've lost the look. Dummy leaf springs with concealed coils doing the actual work are a pretty good compromise. If you want something good for beginners, I would not use SS for the drivers. It can be too frustrating to machine. Also, if I hadn't done quite a bit of casting I would stay with aluminum and zinc (or other low temp white metals). These, however, need a tire shrunken on and so another job. Only if I wanted a really big project would I try brass and cast iron rather than have them commercially done. Victor Lacy /\_/\TrotFox\ Always remember, ( o o ) AKA Landon Solomon \ There is a \./ [EMAIL PROTECTED] \ third alternative.
Re: Boxpok driver model preview other questions
- Original Message - From: Harry Wade [EMAIL PROTECTED] To: Multiple recipients of sslivesteam [EMAIL PROTECTED] Sent: Monday, October 28, 2002 7:55 PM Subject: RE: Boxpok driver model preview other questions The aftermarket wheel makers in the U.S. have developed profiles with superb operating charateristics. If I were doing it I would emulate one of those. Good suggestion, Harry. Impressed by their appearance, I shoehorned Gary Raymond 1/32 wheel sets into a couple of Accucraft trucks fitted them to the tender of my 1/32 US Mogul. Over the last couple of years this has run over a fair number of UK layouts, in Holland at DH with ne'er a problem. Now these wheels look good. Some rather casual work with my faithful Mitutoyo caliper suggests a thickness of 5.2mm (0.205) a back to back of 40.25mm(1.585)The face of the flange has a curve at perhaps a final angle of 20 degrees, the back a slight rounding, contrasting with the GIMRA Standard 10degree angle both face back. Difficult to measure flange thickness with this profile but not far off the standard 1.5mm. So feel like risking a Raymond type profile on your drivers, Ken? Stewart Hine a number of years ago, to his satisfaction mine, showed that you could get away with a 5mm wheel if the flange face angle was increased to 20 degrees the b2b to 41mm. 'Rounding' the flange was also recommended. Despite all that I confess to using basically GIMRA std specs but with more flange 'rounding' to give a nicer profile. Richard Donovan, GIMRA Technical Secretary, is hosting a debate on stds tolerances in the current GIMRA Newsletter Journal. The aim is more to devise a set of acceptable tolerances (eg. do I /do I not, bin this expensive wheel casting I have just turned up!) for wheel track rather than to obtain a better profile wheel. Art Walker, Guildford, England
RE: Suspension [was; Re: Boxpok driver model preview]
There is a great article in this quarters G1MRA newsletter about model leaf springs. The author is making working model leaf springs from a stack of thin plastic sheet (transparency film?) and also another style from a music wire encased in a flexible silicone casting. It seems that the modulus of elasticity is the problem and most metals are too stiff when scaled properly. Both of these solutions are really creative but are more appropriate for rolling stock that isn't subject to the heat and flammable surroundings of live steam locos. Last month the newsletter feature an article about the construction of an electric tank locomotive that had working coil springs hidden inside of the cosmetic leaf spring castings, Cool! In a nutshell: making the leaves hollow wouldn't change the flex of the spring much as the amount of flex (deflection of a beam) is determined greatly by the outside dimensions (I'm simplifying greatly) of the cross section. Removing material from the center reduces weight but doesn't have as great of an effect on flexibility as does removing the material from the outside. This is shown very nicely in I-beams. (think of an I-beam as a square section with one side removed and the other moved to center to balance) Ken This is something I've been curious about for a while now. Why are real springs too strong? Are our locos not heavy enough or is it a problem with the volume of metal used in the springs? Could real leaves be made with hollow sections? I know it'd be a lot of work but this is just for the sake of understanding... Is there not some lighter metal that could be used, or do they get too malleable at the 'correct' flex range so that they'd be easily bent? Curious foxes want to know! Trot, the fox who's not a rivit counter, really..! On Mon, 28 Oct 2002, Jeanne Baer wrote: I would definitely spring the drivers. Even in gauge 1 the engine will run much happier with springing. Equalizing is something else again. It's complex and fiddly (especially if you equalize across the chassis as well as on each side) and won't get you much for your trouble compared to the gains from simple springing. Also, you cannot get the exact prototypical look using leaf springs. If you copy the full size exactly, the springs are too stiff. To correct that you can go undersize with the leaves and pack the stack. But then you've lost the look. Dummy leaf springs with concealed coils doing the actual work are a pretty good compromise. If you want something good for beginners, I would not use SS for the drivers. It can be too frustrating to machine. Also, if I hadn't done quite a bit of casting I would stay with aluminum and zinc (or other low temp white metals). These, however, need a tire shrunken on and so another job. Only if I wanted a really big project would I try brass and cast iron rather than have them commercially done. Victor Lacy /\_/\TrotFox\ Always remember, ( o o ) AKA Landon Solomon \ There is a \./ [EMAIL PROTECTED] \ third alternative.
Re: Suspension [was; Re: Boxpok driver model preview]
Hi Trot. One of the dodges used in the smaller ride on scales is to make the spring leaves out of Tufnol - the resin bonded paper or fibreglass cloth insulating material (SRBP or SRBC) as used for the backing of printed ciruit boards. This is available as quite thin (down to1/32 or less) sheet. This is cut into strips the width of the spring leaves, and bent round a suitable curved former (aka coffe can!) and heated until it discolours. This gives a permanent curved set to the leaves. These Tufnol leaves can be interleaved with steel ones if needed to get the spring rate right. The problem is that the weight of a model of a loco varies as the cube of the scale, so a 1:10 scale model of a 100 ton model has a scale weight of 1:1000 of the original weight, ie 1/10 of a ton = 224 pounds. The spring rate does not scale at the same rate, so the springs end up too stiff. We complicate the issue because since models do not duplicate the construction of the prototype, their actual weight is wrong anyway! Jim Gregg. At 03:44 PM 10/28/02 -0500, you wrote: This is something I've been curious about for a while now. Why are real springs too strong? Are our locos not heavy enough or is it a problem with the volume of metal used in the springs? Could real leaves be made with hollow sections? I know it'd be a lot of work but this is just for the sake of understanding... Is there not some lighter metal that could be used, or do they get too malleable at the 'correct' flex range so that they'd be easily bent? Curious foxes want to know! Trot, the fox who's not a rivit counter, really..! On Mon, 28 Oct 2002, Jeanne Baer wrote: I would definitely spring the drivers. Even in gauge 1 the engine will run much happier with springing. Equalizing is something else again. It's complex and fiddly (especially if you equalize across the chassis as well as on each side) and won't get you much for your trouble compared to the gains from simple springing. Also, you cannot get the exact prototypical look using leaf springs. If you copy the full size exactly, the springs are too stiff. To correct that you can go undersize with the leaves and pack the stack. But then you've lost the look. Dummy leaf springs with concealed coils doing the actual work are a pretty good compromise. If you want something good for beginners, I would not use SS for the drivers. It can be too frustrating to machine. Also, if I hadn't done quite a bit of casting I would stay with aluminum and zinc (or other low temp white metals). These, however, need a tire shrunken on and so another job. Only if I wanted a really big project would I try brass and cast iron rather than have them commercially done. Victor Lacy /\_/\TrotFox\ Always remember, ( o o ) AKA Landon Solomon \ There is a \./ [EMAIL PROTECTED] \ third alternative.
Re: Suspension [was; Re: Boxpok driver model preview]
All those drawbacks of scaling springs is why a lot of modelers prefer equalization without springing. This is done in scales as small as H0 and it's not really that difficult from what I've seen (I haven't done it myself yet). regards, -vance- Vance Bass Albuquerque, New Mexico, USA Small-scale live steam resources: http://www.nmia.com/~vrbass
