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Gould Crane
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robertb@smartchat.net.au
Ken, The easy way to get one of these kits without the worn dies issue is to buy the Gould version. Here are some new unopened kits currently on ebay. Prices from $33 to $45:- Robert Bogie
On 7/01/2023 11:02 am, Ken Adams wrote:
I've had the Gould/Tichy 120 ton crane kit on my to eventually buy and build for decades but I got a wiff in this discussion that that they dies are worn and that I should be looking for an old kit made up maybe 10 or more years ago. |
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If the tooling, molds are worn, that is partially good news, indicating that they likely have been used a lot… therefore lots of sales… yes?
-- Ted Larson trainweb.org/mhrr/ -------- NASG.org -------- https://www.nasg.org/Clubs/RegionsMinnesota.php GN in 1965 |
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Looks like the scarcity sensitive dealers have caught on...
-- Ken Adams Covid Variants may come and go but I choose to still live mostly in splendid Shelter In Place solitude Location: About half way up Walnut Creek Owner PlasticFreightCarBuilders@groups.io |
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I have heard that aluminum molds don't last nearly as long as steel molds. Maybe Dennis can comment? Dick Schweiger (C&BT) proudly told me once that his molds were made of steel. The Branchline box cars mold that I saw was made from aluminum. With CAD files, I guess molds can be recut once they wear out? On 1/7/2023 5:58 PM, Ted Larson via groups.io wrote: If the tooling, molds are worn, that is partially good news, indicating that they likely have been used a lot… therefore lots of sales… yes? --
Tim O'Connor Sterling, Massachusetts |
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Philip Dove
From what l have heard an aluminium mould is shorter lived than a steel mould. Iirc l think an aluminium mould will has a life of about 3,000 mouldings. |
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Dennis Storzek
On Sat, Jan 7, 2023 at 04:58 PM, Ted Larson wrote:
If the tooling, molds are worn, that is partially good news, indicating that they likely have been used a lot… therefore lots of sales… yes?Back at this now that the traffic has subsided. The problem with the above statement is most of those sales came 5, 10, or 20 years too late to convince the manufacturer to remain in, and keep investing in the business. On Sun, Jan 8, 2023 at 09:37 AM, Tim O'Connor wrote: I have heard that aluminum molds don't last nearly as long as steel molds. Maybe Dennis can comment?Fred Becker of Front Range Products made that very same statement to me years ago and you see how that worked out for him. Cutting a new mold cavity is not trivial as far as machining time is concerned. Granted, the design work does not have to be redone, but that's only 10-15% of the total. If the product is past the initial sales "hump", one has to think long and hard whether one wants to commit those resources to a product that's past its prime, earnings wise, or just commit those resources to something new. The best course, to my way of thinking, is to pay a little more up front to get years of trouble free operation to capture years of continuing sales. There are two things that can take a tool out of operation; accumulated wear, and a 'crash', where something gets caught in the mold and closed on. Hard steel tooling combats the first, but is not immune from the second. Years ago Accurail lost a boxcar body tool on the second shot; the setup techs hanging the tool made the first shot, didn't notice that the ejector stroke was not long enough to push the part entirely off the core, and let the press close again on the part, mangling the blades that make the Z bar eaves. Luckily it was a quality molder with a good reputation to uphold, and they paid for the repair. There are lots of materials that injection molds have been made of. Some are cast bronze alloy against plaster masters; the tooling for the intricate City Classics buildings were made this way. The casting process picks up the detail, but holding dimensions is a problem. Firms that had a background in engraving liked to use brass because it cuts well with the traditional form ground cutters engravers use, but it's not very hard. Grandt Line did most of their work in brass, as did Heljan, the Danish building kit manufacturer. Walthers even had them do some car kits in brass tooling, remember the 50 single sheathed automobile car and "beercan" tankcar? Brass tooling. Aluminum was the choice for the early CNC artists because it cuts fast and rarely breaks cutters. Front Range, Intermountain, and Tichy were big users. It's harder than brass and as long as you don't crush it, it's adequate for our industry's run sizes. Years ago many model kit tools were made of P-20 "prehard" steel, steel that was heat treated to a mid-range hardness that could still be cut with common High Speed Steel milling cutters, but the advent of EDM (Electro Discharge Machining, basically spark erosion) pretty much ended that, because now cavities can be sunk in fully hardened tool steel. I'm most comfortable with this process, although we have some aluminum tooling also. The most recent development is "hard milling" coated carbide cutters and toolpath strategies that allow fully hard tool steel to be worked on a CNC milling machine. I understand Brian of Tahoe Model Works is a big fan of this. In conclusion, all these methods can yield serviceable tools for our industry if they're taken care of. Dennis Storzek |
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Tony Thompson
Thanks for the comments, Dennis. I remember when I worked at the Vernon plant of Alcoa during college, helping out in the metallurgical lab, I was told that the most skilled and valued people in the plant were the die sinkers, making both extrusion and forging dies. All steel tooling, and though I don’t remember specific numbers, it was mentioned that tools were rated in how many extrusions or forgings could be made before replacement. Some of the more complex dies had distinctly shorter lives.
Tony Thompson |
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