Erector set part number 'ED' triple drum hoist

Flash forward a year and I need to make more of these ED triple-drum hoists. One thing I enjoy about this hobby is trying different things to improve quality and/or save time. One part that had an opportunity for improvement was the drum side plates.

I’ve made them in the past by punching out the disk, then use spray adhesive to glue the blanks to a paper template. The 4 slotted holes were then punched on my Roper Whitney 218 punch press. Fortunately the tolerances aren’t too tight, so eyeballing the punch on the paper outline is “close enough”. However, it takes time to print and glue the templates to the disks, so time for an improvement.

Idea was a fixture that locates on the OD of the disk. The fixture would have clocking marks at 90 deg. for orientation. I started by knocking a hole in a plate of aluminum on the CNC Bridgeport. I could have used a boring head and crept up on the hole for a decent fit (0.010” clearance) to a disk, but went the CNC route. Pretty simple with this machine and its ancient (1984) technology. Program takes a V18 (variable 18?) for the diameter, and a V49 for the cutter diameter. The CNC controller automatically compensates for the cutter diameter, not that it’s tough math. Then issue a G76 command which hogs a hole to the V18 specified diameter.

Before running the routine, I dry ran the program with a laser center finder in the spindle. Just eyeballed the path on a scribed line and saw it was executing as expected. Stuck in an end mill and let the CNC do the work.

I purposely put in too small of a hole so the final diameter could be crept on. Made the final pass for about 0.010” clearance. Then mounted a carbide scribe and scratched in indexing marks at 90’s.

Used a master part to align the fixture to the RW 218 table and clamped in place. Made a sheet metal tool with a hook on the end to grab and rotate the blank. The process goes pretty well, takes me about a minute to knock the 4 slots into the disk. Took me about 4 hours from start to finish to make up 140+ disks.

Thanks for looking.


Bruce

20180923_165559.jpg
20180924_163617.jpg
20180924_163634.jpg
20180929_161254.jpg
 
On to the cranks and the stop collars. Gilbert included a part# P24 crank in Erector sets. I have lots of them in my inventory of parts, so used nice originals to make the cranks. The ‘ED’ hoist has wooden knobs on the cranks which are held in place by peening over the end of the crank to capture a washer and the knob on the crank handle.

Started with the knobs. Turned a dowel down to the correct diameter. Then center drilled and drilled a hole for the crank handle. Next, a countersink was put in the end with an end mill. Used a grooving tool (MGMN 200) to cut some grooves (to match the original design) into the knob and parted.

Then to the drill press to put a countersink on the end of the crank handle. It’s a lot easier to peen the end of the crank when it’s at a knife edge. Used a drill bushing set over the crank handle to hold the drill bit on center. Then mounted the P24 crank in a jeweler’s vise, supported the back of the handle with a punch, and dropped on the knob and washer. Peened the end of the crank with a punch and hammer.

The ‘ED’ uses a number of stop collars which are Erector set part# ‘BH’. These are 5/16” diameter brass with an 11/64” hole through the middle, and a 6-32 tapped hole on the side. I used the same drill bushings that were used to make the hubs for the drums.

Last part made was the 1/16” diameter music wire friction brake. This was bent on the hoist with the drum in place. That gives a pattern for bending more using one of the brake drums as a pattern for the curved portion of the wire.

Time for the final assembly; just a matter of feeding parts on the axles, tightening set screws and adjusting the position of parts on the axles. You can see from a couple of the photos how the upper crank can move side to side to engage either just the upper drum or simultaneously engage both the upper and lower drums. Another part ready for an Erector set show in your neighborhood!

Bruce

View attachment 236487 View attachment 236488 View attachment 236489 View attachment 236490 View attachment 236491 View attachment 236492 View attachment 236493 View attachment 236494 View attachment 236495 View attachment 236496
Dear Bruce: Would you be interested in a set of 3d files of each of the erector set parts. I have been drawing each part out in Soildworks so that I can redraw the more complex models that are hard to build using the old manuels, or has some else done this type of project. Tim King
 
Back
Top