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April 2010 Group Picture
There are hobby machinist groups scattered around the USA including a small HSM group in Connecticut. Our CTHSM group is congenial and freewheeling:
no rules, no dues, just people getting together to learn new techniques plus share thoughts on machining and other topics that arise. Meetings are held in member shops, nominally on the second Sunday of the month at 2pm. Anyone interested in attending a meeting please contact me
(via the link below on this page)for more info and travel directions.
The May 15th 2022 meeting was at Ralph's shop in New Hartford, CT.
Ralph showed his setup for investment casting of bronze and described the overall operation.
At far right is the 3D printer used to produce a plastic image of the item to be cast. This printer uses a liquid plastic that hardens when exposed to UV light; each exposure hardens a thin layer of plastic in a little tub in the bottom of the printer, the platform is raised a few thou and the next layer exposed, etc. to produce the complete image.
The small white table holds the material for the mold. The drill is used to mix the molding material prior to pouring it into the container surrounding the plastic image of the part to be cast.
At left, the Kaya Cast machine contains a vacuum pump used to remove the air bubbles within the casting material. The container is then placed in the programmable oven at far left and the temperature is raised in stages to slowly dry the casting material; rapid drying would cause cracking of the mold. Once the mold is dry, the temperature is raised to burn (or evaporate) the plasic image - which takes about 12 hours.
The bronze is then melted using a graphite crucible in the oven. The mold in its container (warmed to avoid cracking) is placed in the Kaya Cast, the bronze is poured into the mold, and the vacuum is used to remove any air bubbles - the mold material is sufficiently porous to allow this. Once the bronze solidifies the result is placed in a bucket of water while still hot which causes the mold to crack and fall off.
Ralph displayed example plastic images and some bronze valve handles which he cast. Overall a great presentation where we learned a lot about investment casting.
Eric demonstrated the 4 piston model steam engine shown at right, operating on low pressure air. This unusual design has a cross-link scheme to operate the opposing pistons.
Unfortunately, I botched my camera settings so most of the pictures from this meeting are blurry.
Fortunately the following picture of Ralph's locomotive is quite clear. He hopes to complete this project next year. Investment castings are just one more supporting step in the build of this locomotive. Note the rivets on the tender - there are over 2000 !!!
Here's an interesting variation on using the Kant Twist clamp parts available to CTHSM members.
See: Kant Twist Knurler at HSM
The June 12, 2022 meeting will be at Roger's shop in Huntington (?), CT.
Per the COVID guidance, all attendees should be vaccinated. Parts for Kant Twist clamps will be available at this meeting.
As usual, bring items for demonstration and/or discussion. Plus items for the sale/swap/free table.
Home shop machining is often a solitary hobby, as are most hobbies now according to "Bowling Alone".
The CTHSM group is an attempt to get area HSM's to know one another and thus make our hobby a little less solitary.
The much larger NEMES HSM group is 2-3 hours away so we share some members and occasionally have visitors from that group.
The CTHSM group has been meeting since November 2008, mostly on the 2nd Sunday of the month at 2pm, but we deviate from this with some regularity. The January meeting is not held since Cabin Fever conflicts, February has seen a couple meetings cancelled due to weather, the May meeting is on the 3rd Sunday to avoid a conflict with Mother's Day, and we don't meet in July because many members are on vacation. Over time our meeting schedule has become predictably irregular...
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Pictures from our unusual "Music Machine Meetings"
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