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- Nov 23, 2014
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- 2,606
Yeah, still reproducing old Erector set parts . . . This one is pretty esoteric, the part number GN airplane swivel. First the obligatory history lesson . . .
Gilbert introduced an Erector set in 1928 that built a number of different airplanes. The set came with a fuselage, two wings, horizontal/vertical stabilizers, propellers, a 110V motor and other parts to build up different styled airplanes. The components were sheet metal and NO, the plane models did not actually fly. The child could simulate flight by hanging their model from the ceiling and power the motor through the part number GN swivel unit. The swivel base was wired to ground, a hot wire tied to a brass disk and a rotating wiper to carry power to the motor on the bottom of the swivel. I chuckle at the original design of 1928 where the model was suspended directly by the 110V power wires to the motor. I’ll have to goggle when UL became an entity. The design was changed by 1930 to suspend the model by a cord, so no more house fires playing with the airplane at that point.
The swivel unit was made from common Erector set parts and a few “no part number” pieces. The main working components were CI brass segments (see another post of mine for the construction of these), CM fiber disks and a npn brass wiper.
First step was making the CM fiber disks. These are 1 ¼” diameter and made from a non-conductive insulating material. I made a punch and die for these years ago which cut a lot of time from my previous method of punching a center hole, stacking a number of rough band sawed disks on a bolt arbor and turning to diameter on the lathe. Invariably the cutting tool would catch on a disk which stopped it while the rest of the stack on the bolt arbor were spinning. That method required a lot of slow pecking to get the disks to diameter. Knocking them out on the Roper Whitney #218 press goes much quicker.
I use a RW No. 5 Junior to punch out a center 9/32” hole. I made a transfer punch guide a while back from an aluminum round with a tapped hole and a steel arbor. The CM disk has 8 holes on 1” spacing across the circle. The fixture goes pretty quickly, slip a disk on the arbor which is screwed into the aluminum punch guide. Set the assembly on a bench block and transfer punch the holes. The eight holes are then punched with an 11/64” punch in a RW No. 5.
The CM disks get a 5/16” OD brass hub for attaching to an axle. I make heavy use of hardened drill bushings when making these parts. The hub has an 11/64” hole up the center which I do with a drill bushing that fits over the 5/16” brass and guides the 11/64” drill bit with a central hole. This allows me to skip the center drilling step.
After center drilling, a shoulder is cut to 9/32” OD. This fits into the fiber disk. The hole is countersunk to aid in peening the brass hub onto the disk. A second drill bushing is used to locate a 6-32 tap drill hole which is done on the lathe with a hand drill. Then the hole is power tapped with a cordless drill. Next step is to part the hub off. The tap hole bushing is the same width as the length of the hub, so it does double duty by indicating the length of the hub. I hold the hubs in a little fixture with a center knock out pin for cleaning up the ends from parting on the belt sander and grinder with a Scotchbrite disk.
The hubs are peened onto the disk using a Delrin block with a pin for holding the hub in place. The hub is set on the pin, disk set on top and the hub peened over using a large ball bearing and a whack with a hammer.
Next component is the brass wiper. These have a raised area for a point contact with the disk made from Erector part# CI’s. I made a simple die from a couple of pieces of CRS which were pinned together with ¼” dowels. One of the plates was drilled and reamed to 0.249, other to 0.251 so the dowels locked to one plate and slipped on the other.
Looks like I forgot to shoot a picture of it, but the two plates were set in the mill with a piece of paper between the two and a 1/16” hole was drilled through both at the center. My plan was to set a piece of 1/16” drill rod on one half, set a brass strip between the two plates and give it a whack with a hammer to form an embossed area in the middle of the brass strip. After drilled, I used a die filer to open up one side of the die for clearance between the brass and die side opposite the 1/16” drill rod. The set up works pretty well though in retrospect I could have put some pins in the dies to locate the edge of the brass strip for quicker alignment than just eyeballing it. On the other hand, the world wide need for this part is probably 10 in the next 5 years, so eyeballing a few should be fine.
Next step was punching an 11/64” hole for attaching to a CM disk, and a 90 deg. fold with a Pexto 793 flange tool.
The GM uses a 5/16” brass spacer bushing 0.200” long with an 11/64” hole. Used a drill bushing to knock in the center hole, then parted to length. Used the same holding tool for cleaning up the parted ends as with the hubs.
Rest of the work was just screwing together the rest of the common Erector set parts to make up the swivel assembly. Not a huge money maker as they sell for $30 - $50 when listed on eBay, plus not a huge market as the Gilbert Airplane sets are few and far between. But adds to my list of stuff for sale at toy shows.
Thanks for looking.
Bruce
Gilbert introduced an Erector set in 1928 that built a number of different airplanes. The set came with a fuselage, two wings, horizontal/vertical stabilizers, propellers, a 110V motor and other parts to build up different styled airplanes. The components were sheet metal and NO, the plane models did not actually fly. The child could simulate flight by hanging their model from the ceiling and power the motor through the part number GN swivel unit. The swivel base was wired to ground, a hot wire tied to a brass disk and a rotating wiper to carry power to the motor on the bottom of the swivel. I chuckle at the original design of 1928 where the model was suspended directly by the 110V power wires to the motor. I’ll have to goggle when UL became an entity. The design was changed by 1930 to suspend the model by a cord, so no more house fires playing with the airplane at that point.
The swivel unit was made from common Erector set parts and a few “no part number” pieces. The main working components were CI brass segments (see another post of mine for the construction of these), CM fiber disks and a npn brass wiper.
First step was making the CM fiber disks. These are 1 ¼” diameter and made from a non-conductive insulating material. I made a punch and die for these years ago which cut a lot of time from my previous method of punching a center hole, stacking a number of rough band sawed disks on a bolt arbor and turning to diameter on the lathe. Invariably the cutting tool would catch on a disk which stopped it while the rest of the stack on the bolt arbor were spinning. That method required a lot of slow pecking to get the disks to diameter. Knocking them out on the Roper Whitney #218 press goes much quicker.
I use a RW No. 5 Junior to punch out a center 9/32” hole. I made a transfer punch guide a while back from an aluminum round with a tapped hole and a steel arbor. The CM disk has 8 holes on 1” spacing across the circle. The fixture goes pretty quickly, slip a disk on the arbor which is screwed into the aluminum punch guide. Set the assembly on a bench block and transfer punch the holes. The eight holes are then punched with an 11/64” punch in a RW No. 5.
The CM disks get a 5/16” OD brass hub for attaching to an axle. I make heavy use of hardened drill bushings when making these parts. The hub has an 11/64” hole up the center which I do with a drill bushing that fits over the 5/16” brass and guides the 11/64” drill bit with a central hole. This allows me to skip the center drilling step.
After center drilling, a shoulder is cut to 9/32” OD. This fits into the fiber disk. The hole is countersunk to aid in peening the brass hub onto the disk. A second drill bushing is used to locate a 6-32 tap drill hole which is done on the lathe with a hand drill. Then the hole is power tapped with a cordless drill. Next step is to part the hub off. The tap hole bushing is the same width as the length of the hub, so it does double duty by indicating the length of the hub. I hold the hubs in a little fixture with a center knock out pin for cleaning up the ends from parting on the belt sander and grinder with a Scotchbrite disk.
The hubs are peened onto the disk using a Delrin block with a pin for holding the hub in place. The hub is set on the pin, disk set on top and the hub peened over using a large ball bearing and a whack with a hammer.
Next component is the brass wiper. These have a raised area for a point contact with the disk made from Erector part# CI’s. I made a simple die from a couple of pieces of CRS which were pinned together with ¼” dowels. One of the plates was drilled and reamed to 0.249, other to 0.251 so the dowels locked to one plate and slipped on the other.
Looks like I forgot to shoot a picture of it, but the two plates were set in the mill with a piece of paper between the two and a 1/16” hole was drilled through both at the center. My plan was to set a piece of 1/16” drill rod on one half, set a brass strip between the two plates and give it a whack with a hammer to form an embossed area in the middle of the brass strip. After drilled, I used a die filer to open up one side of the die for clearance between the brass and die side opposite the 1/16” drill rod. The set up works pretty well though in retrospect I could have put some pins in the dies to locate the edge of the brass strip for quicker alignment than just eyeballing it. On the other hand, the world wide need for this part is probably 10 in the next 5 years, so eyeballing a few should be fine.
Next step was punching an 11/64” hole for attaching to a CM disk, and a 90 deg. fold with a Pexto 793 flange tool.
The GM uses a 5/16” brass spacer bushing 0.200” long with an 11/64” hole. Used a drill bushing to knock in the center hole, then parted to length. Used the same holding tool for cleaning up the parted ends as with the hubs.
Rest of the work was just screwing together the rest of the common Erector set parts to make up the swivel assembly. Not a huge money maker as they sell for $30 - $50 when listed on eBay, plus not a huge market as the Gilbert Airplane sets are few and far between. But adds to my list of stuff for sale at toy shows.
Thanks for looking.
Bruce