Building a Berkshire

[gcarsen]

Yes a tumbler can leave that finish!

The one I have works great for smaller parts. the bowl is about 16 inches across. it works good on parts that are long up to about 8 inches, square parts 3 to 4 inches. the next one I get may be the box style so I can run longer parts.
typical run time is about 1 hour, sits over in the corner working by itself!

I use the resin "pellets". they come in all sizes, shapes and base material. one thing to keep in mind, If you have allergies to resins, or fiberglass, get the ceramic pieces.

several things to keep in mind, you do not need to use there "special" polishing compound! the first time I was around these I took a real good sniff of it straight from the container, and I knew the smell, took me a bit to remember where I smell it all the time, its shampoo! I typically use Simple Green, does a good job, acts as a good wetting agent and lube, keeps the parts clean, and does not rust. typically about a 50/50 mix with water. start it up, slowly add your solution till the media starts tumbling good, but not enough to get standing water in the bottom. drop your parts in and let it go. check periodically till you get the finish you want.
several things, the media does wear out over time.
you need to periodically clean the bowl, and media. after a while it get too many fines and it stops working, but interestingly , if the solution has some "dirt" in it it can actually give you a nicer matte finish all over the whole part. I run aluminum, and steel parts all the time and do nothing special for either.

you just need to play with it. different shapes of media, size , and amount of solution to get what you want.

just like tumbling and cleaning cartridges brass, start with some course, and end up with walnut shells as the final. I ran some aluminum parts that way. ended with walnut shells and you could almost see your self in the finish.

you can make your own several ways, I use to have a old paint can that was about 1/3 full of media, drop in a glass or 2 of Kerosene, drop the parts in, grab in the lathe chuck and turn it on slow speed for a while, the parts tumbled and rolled around giving great results. they where trapizoidal shapes about 3/16 across. perfect for really small parts.
the comercial ones are basically a tub with an electrical motor strapped to the side slinging a weight around ofbalance to vibrate the whole thing!
Grant

[gcarsen]

Busy day getting other things done, or going! but here is todays part to add to the pile!

Bolster Retaining Bar Print 7D 4 req.

small, but something, ran the parts through the glass beader. the helper did not tell me we needed new gloves! the left one is missing all 5 fingers! explains why he is always so dirty after glass beading,,,
Grant

[gcarsen]

not much today, TGIF! but at least one more detail.

Roller Wear Plate Part7D2A ,Print 7D 2 req.

Since this is a wear plate, I started with some tool steel I had on the shelf. quick machine job, Heat treat and grind. left it thick to finish at assembly.

One suggestion or thought for use on other similar parts , this part is .125 thick, by the time you run the 10-32 threads in, you do not have a whole lot of thread engagement. that is 4 threads and by the time you add the customary chamfer, maybe 3 threads. and if you do the standard threading with a tap, you only have about 67/75% of the thread profile. I was always taught you will not get your full strength out of a threaded hole unless the thread engagement length is 1.5 times the diameter of the threads. in cases like this I usually use a form tap, you drill a little larger start hole, then run the form tap through like a standard tap. it forms the thread into the hole leaving a stronger thread (a higher percent of the thread profile is left). a couple of other advantages, the thread finish is outstanding compared to the thread cut with a standard tap. and you have no chips to deal with ( a big plus in blind holes in production work and the need to clean them out!) you have a higher percentage of thread in the hole, with charts you get up to 85% profile. and the taps are a whole lot stronger and less likely to break. you just need to make sure they have adequate lube! in alot of ways I think form taps are highly overlooked where they can have huge benifits,,,


But in this case this is just extra though as the wear plate is not in a structural load. the threaded holes just keep the plate in position. and the extra strength is not needed,,
Grant

[gcarsen]

Ok, here is some important info. You can never have enough Reference material if you want to build a very well detailed model. Jim bends over backward supplying everything he can. several other sources,
California Railroad Museum, they have the Lima archives and can supply a ton of prints and info, you can get a list of the drawings and go crazy!

One definite Book if you are building a Berkshire is
"Berkshires of the Nickel Plate Road" written by Kevin J. Holland, published by TLS Publishing.
it covers the story of them pretty well, divides it up into classes and explains the differences in them. and how they changed through there working years. tons of good clear photos!

another
"Super Power Steam Locomotives" written by "richard J. Cook, published by Golden West Books
old book, long out of print. it does a pretty good job covering the history of the "Super Power" locomotives. has a lot of good pictures. a lot of them out of lima showing them being built. shows to that you could use a lot of Jims castings to build other locomotives out of this time period. as the basic designs where pretty close and used pretty standard parts.

And then the old standby, the "1942 Locomotive Cyclopedia" pretty well covers about everything on the locomotive one way or other.

One of the University Libraries also has a large # of the prints from the NKP archives if I remember right, in there possession. they have 2 rolls of micro film full of Berkshire info and prints, if you search back on Chaski here you can find it,, just trying to find a micro film reader now days is a search of its own! everything is digital now!!

A ton of fun starting! and who knows how long this project will take!
Grant

[gcarsen]

Ok, Todays finished piece, spent time lining up material and such for other pieces and roughing some others out.

Shim , Part 8F8, Print 8F, 2 req.
as it is a shim, I left it about .120 thicker to finish at assembly once we have all the stack up.

[Fender]

Hi,
Very fine work on your berk. There is another out-of-print book on this subject by John Rehor.

[LivingLegend]

And let's not forget the Allen County Historical Society as an information source.

LL

[apm]

Just wondering when it comes to tumbling, what type of material removal rates do you actually see in the finished tumbled part? I assume there has to be some sort of material removal taking place to get such a beautiful finish is it noticeable or not?

[kvom]

Based on this thread, I'm going to order some ceramic media from mcmaster and use the can-on-a-lathe method to try it out.

Since I started machining 4 years ago the only injuries I've had have been cuts by burrs or deburring tools.

[gcarsen]

I will admit that I have never measured the parts after tumbling! the matl lost will probably most depend on your starting finish, it is just a surface finisher maybe a tenth or 2. it does more removal on corners than anywhere else. you can figure your times and media, and you can get the finish you want as well as a few thousands or so radious on the corners of your parts, you still need to debur your parts properly first though, if you leave a big hairy bur, it will still be there, maybe just smothed a bit, but it will be a nice looking burr then!!

next, an item that is probably required by most on here, or eventualy will!! up to 6 months ago, with out aid, I could count the hairs on a Flea's head, not any more!! My eye sight is still good, just not the real little fine stuff any more, I gues I am getting older. I have a real "OptiVisor" made by "OptiVisor" the real deal. it works great to get back to seeing the real fine things! not that I count many things on a Flea's head, but it helps with the model building and my tool work!
it was given to me by one of my ex employers and I never used it, as I did not need it! but lately I have had it permanently on my head! works great no problems, crystal clear, never have any problem! I took it home for use there, and I bought a cheap knock of from Mcmaster Carr. what a joke, it keeps falling apart just sitting on my head! head cushion band fell of, retaped it on, snaps holding the lense in keep falling out, then your down on the ground trying to find them, and you would probably need the darn thing to see it!, the friction knobs that hold the lenses in adjustment keep falling off! just a royal piece,,, if you need or want one, do yourself a favour and step up and pay the extra money for the good one!!
Grant

[gcarsen]

Another detail to add to finished pile
Sleave-Pedastal binder Print 7C, 2 req.
I left it about .125 longer to finish at assembly once we have the lead truck casting machined and ready for assembly.
Grant

[gcarsen]

Another detail to add to finished pile
Sleave-Tie Bar ,Print 7D, 2 req.
I left it about .125 longer to finish at assembly once we have the lead truck casting machined and ready for assembly.
and also its a good idea to get knowledgable with a print pack, then you can group like parts together to save time, matl, and set ups!
Grant