Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Model & Toy Steam Engines – Stirling Cycle – Flame Lickers – Small Antique Originals => Topic started by: Jim on February 10, 2021, 04:46:49 pm
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Thanks Dennis, yes I can imagine how 3D printing would be a huge help.
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Thanks Dennis, what is the former usually made out of?
I do remember now some of the flywheels that you have cast.
For die cast, can the graphite blocks be used more than once?
Formers used to most always wood but can be other things
now quite a few now use 3D printed plastic ?
Yes graphite blocks can be used repeatedly
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Those machine tool castings are pretty smooth for a mold. You can see the sprue from the seams of the mold.
Some times castings get tumbled to clean them up. Now companies use lost wax castings.
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Thanks for the anecdote Bruce, always nice to read about some Jensen back story and a little bit more history.
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Dick H. ( a long time Jensen dealer) told me he had the workshop #100 molds at one time @ found one guy who had the old type of machine that could still accept these dies and had a few NOS parts made from them , there was some kind of issue (I think he kept them to long) @ made Jensen a little nervous and they demanded them back. I assumed they were metal molds , Anyway he sold me nearly all his stock of workshop #100 drive pulleys and I have them to this day. These pulleys are not strong enough in they're own right to turn as is (the spokes break) I had to make a jig that would clamp down on the outside rim and machine them that way , there are 4 different size #100 drive pulleys.
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Thanks Daniel.
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Jim, the pattern piece could be made of many different materials. Wood is perhaps the most common, but metal and clay are also used. Do realize that several impressions can be made into one sand casting frame, so that when you pour, you can get more than one piece out of the process each time.
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Thanks Dennis, what is the former usually made out of?
I do remember now some of the flywheels that you have cast.
For die cast, can the graphite blocks be used more than once?
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Having done some casting i know a little bit
My Jensen engine with cast base certainly looks like sand casting . And yes Jim a former is used and the sand packed around it then the former removed .
The workshop tools look very smooth so either die cast or sand cast then finished ( ie sand paper or file )
Die cast could be a simple as solid graphite blocks ( two halves )
I have played with this and you get a smooth finish and better detail than sand
Cheers
Dennis
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The workshop tools are certainly molded, as seen in the photo above, but the steam engine frames sure look to be sand castings to me.
From my very limited knowledge on the subject, does that generally mean the moulds are wood (or metal?) and the two halves of the mould are made out of green sand, pressed together and then the cast iron is poured in. So it needs a new green sand mould made for each casting?
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I've been to Jensen mfg. There has never been a foundry there, as stated prior , they're not now & never have been set up for that. As Steve Tyner told me a few yrs ago they're one man foundry supplier died & they were behind until they could find another. At 15-20 units of the #20 & #55 each a year...foundries aren't exactly knocking at their door. Also the occasional #50.
Thanks Bruce.
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The workshop tools are certainly molded, as seen in the photo above, but the steam engine frames sure look to be sand castings to me.
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I've been to Jensen mfg. There has never been a foundry there, as stated prior , they're not now & never have been set up for that. As Steve Tyner told me a few yrs ago they're one man foundry supplier died & they were behind until they could find another. At 15-20 units of the #20 & #55 each a year...foundries aren't exactly knocking at their door. Also the occasional #50.
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Nick reminded me of this wonderful casting of a Jensen #100 work shop that Gil bought many years ago at an estate sale -
[attachimg=1]
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Daniel what do you think they would have used for moulds? Would they have been green sand moulds and needed to be formed for each pour or some type of permanent/reusable mould?
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I'd be very surprised if they were Jim, as the size of their shop is such that having an iron foundry in it too would be about impossible, if what I've seen and heard is any indication. There are perhaps still, but were certainly back in the day, a fair number of smaller dedicated foundries around that would likely be glad to run batches from Jensen's patterns from time to time.
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Does anyone know if Jensen's cast iron castings are/were done in house?