Model Building Tips

Tom Washeck writes

These notes are reminders for me if I ever decide to build the Merry-Go-Round Model again.

Erector Set Used

  • A restored (Per Greenberg’s Guide, 1959 Contents List) “No. 10083 Amusement Park Set”

Instruction Manual Used

  • A 1959 Master Builder Manual, Section A, M3974, 58

Finished Size

  • Base = 18 3/4-inch x 19-inch (Without 5 1/2-inch x 5 1/2-inch Sound Effects)
  • Outside Diameter = 18 3/4-inch
  • Height = 22 3/4-inch (23-inch With Flag)
  • Wood Platform Needed
  • With Sound Effects, a 24-inch x 30-inch looks symmetrical and centered, especially with the additional set of steps I built. (see note 18)
  • Approximate Completion Time, including base and sound effects – 35 hours

In the notes below, ** indicate missing parts or inaccuracies in the instructions.

General Notes

Base and Mounting of Model

1. When building the Base, the use of the two MB-18 1/2-inch angle girders instead of overlapping DP 12-inch angle girders with BE 6-inch angle girders to mount the motor provides more stability.

2. Using four CH right angles to attach the MN 12-inch base plates to the MD 2 1/2-inch x 5-inch base plates at the perimeters provides greater stability BUT you will not have enough CH right angles to complete the project as instructed. (See note 8). Using M small double angles for this purpose will work.

3. For modification of the base, see note 6

Center Section Assembly

4. Motor and Drive Train – The Merry-Go-Round must rotate counterclockwise when viewed from the top. Remember this when setting up the drive gears. Grease/oil the motor and gears before mounting the T boiler because it is very difficult to do afterwards.

5. Attaching BN Turret plates with CH right angles to the inside of both ends of the T boiler is no mean feat. One end can be done easily with a long screwdriver. Using internal toothed lock washers (not supplied) under the screw heads with a nut holding the screw to the “to be” Turret side of the internal CH right angles allows the placement of the second turret plate over the screws and the subsequent ability to add and tighten a second nut onto them from the outside.

6. The arrangement of the four C 10-inch girders, as shown in Figure 2, is lop-sided and does not provide a good rigid support to keep the Boiler, and therefore the drive axle, from wanting to wobble. The addition of an MF 1-inch x 5-inch base plate across the upper left end (compare Figure 2 in the manual with Photo 1) between the angle girder and the 12-inch base plate will allow the four brace girders to be attached at 90 deg. from each other, providing much greater stability. There will be one MF base plate left over from making the upper outer ring, see note 7

Top of Model

7. ** The outer top ring only requires 12 MF 1′ x 5-inch base plates instead of the 13 noted in the instructions. See note 6. The construction of the outer top ring and the inner bottom ring, done by overlapping, is a trial and error process to balance the overlaps for weight distribution and getting the best relationship between the four rings for subsequent connections between the four rings. Note: The outer top ring ended up with 116 holes around the circumference and the inner bottom ring had 78 holes around the circumference. There will be 8 square girders attached. Therefore, they cannot be evenly spaced around the rings. It is trial and error to arrange these so the columns do not lean too badly. Note the center right hand girder in Figure 1 of the manual and also see note 15.

8. I assembled the top cone, made from E 5-inch curved girders, a BN turret plate and a pierced disc, as instructed. I found that it was difficult to arrange the 8 CH right angles around the pierced disc and that I would still need the four CH right angles I had used to stiffen up the base plate, see note 2, to attach the cone to the outer top ring. Not wanting to take the base apart, which had now been screwed down to the wood platform, to retrieve the right angles, I used four M small double angles to attach the 5-inch curved girders to the turret plate. These double angles had to be slightly twisted to evenly space the girders but I believe I will be able to straighten them out when I take them apart. I also decided not to attach the cone section to the outer top ring at this time as it would be a nuisance to work around while assembling the main body of the carousel.

Driving Mechanism

9. ** When it came time to assemble the driving mechanism, I only had one pierced disc instead of the two required. Four BT pierced discs come with this set. One was used on top of the boiler, one was used at the top of the “cone of curved girders” and one was used in the center of the four B 5-inch girders bracing the inner top ring. Two possible solutions arose. The first was to disassemble the top cone and use that pierced disc, replacing the pierced disc and turret plate with a CR Special turret plate with hub. Using this turret plate with the small center hub would make it easier to properly mount and orient the CH right angles but I would still be short by four. I didn’t want to take the base apart to retrieve the remaining four angles, see notes 2 & 8, and besides, I had already mangled four double angles. A second reason was that the small hub of the special turret plate is only pressed/crimped into the center of the turret plate. I was not sure whether this connection would be sturdy enough to withstand the starting and stopping force of the rotating carousel and whether the turret plate, supported only in the very center, would hold the entire weight of the carousel as it would do by design. (See note 16) I took the cowards way out and stole a pierced disc from another erector set that I fortunately had.

10. Upon assembly of the driving mechanism and its installation, I found that the design’s reliance upon the set screws of the pierced disks for weight support, rotational motion and spacing of the components, could use some improvement. While support of the weight is essential, the spacing of the driving mechanism and the inner top ring is critical as it effects both the meshing of the pinion gears with the crown gear and the free rotation of the axles that lift and lower the horses. These axles must pass under the inner top ring of CS wheel segments and through a partially covered slot in the C 10-inch girders and there is very little clearance. I picked up some nylon spacers at my local hardware store from those little drawers of specialty parts. The use of 3/4-inch long nylon spacers (3/8-inch O.D. x 0.171-inch I.D; the axles are 0.154-inch O.D, or just under 5/32-inch diameter) between the crown gear and the driving mechanism and between the driving mechanism and the brace for the inner top ring, hold the relationship between the pinion gears, the crown gear and the top inner ring at a fixed distance without relying on the set screws to hold the weight. These spacers, along with two others (see note 16), transfer the weight through the boiler, motor side plates and angle girders directly to the wood platform, removing the weight of the rotating carousel from the P48 Mitre Gears in the motor drive train. The set screws now only have to transfer the rotational motion from the 12-inch drive axle.

Assembly of Horses

11. ** The use of an H 11 hole strip instead of a G 7 hole strip provided full support and proper height for the stationary horses.

12. ** The instructions call for the use of four 8-inch axles for the guides of the horse’s vertical movement. Only two 8-inch axles are part of this set and one is used for the main drive. This set does contain four CZ 7-inch axles and these work well.

13. **The instructions and picture for the installation of the seats is not correct. An MC 1-inch x 2 ½-inch base plate is too long to fit between the C girders and allow the P79 car truck to be screwed directly to the outer bottom ring. I found that the use of a G 7 hole strip was necessary to secure the seat bottom to the outer ring.

14. At this point, I attached the top cone section to the outer top ring of the carousel, and set the main body of the carousel onto the 12-inch drive axle. Adding an 8-inch axle to the top of the existing 12-inch drive axle with a P15 coupling now completed the rotating carousel. I also used a P15 coupling above the top of the U-boiler top to keep the plastic top from rattling. The remaining 5/8-inch of the 8-inch axle allowed just enough room for the Erector flag.

15. The horses just barely fit between the square girders and when they move sideways as part of their motion, the rear feet may hang up on one of the protruding 7/8-inch screws holding the square girders together. This explained to me why one of my original horses had a “broken” leg. I gently rolled the horses across the edge of the table to make them curve slightly inwards. This small amount of curve kept the rear feet well behind the square girders, avoiding further damage. As noted in note 7, one of the spaces for the moving horses may be even narrower than the others and a deeper curve to this horse may be required.

Final adjustments

16. I decided to continue my idea of using nylon spacers for supporting the weight of the carousel. I used a 5/8-inch long nylon spacer to fit between the brace of the inner top ring and the P15 coupling, and 4 5/8-inch of spacers to fit between the top of the coupler and the bottom of the top hub. This arrangement now allows the entire weight of the carousel to be transferred to the base. I even removed the set screw from the pierced disc at the top of the cone section so that all of the rotational motion is transferred by the main 12-inch drive axle. The use of a CR special turret plate with hub in place of a non-existent fifth pierced disc, (see note 9) would work but these spacers are themselves an addition to the contents of the Amusement Park set. The only resistance to the rotational motion provided by the drive axle is the points of contact with the lowest spacer as the other spacers move with the carousel. I put a little grease on both ends of all the spacers anyway.

17. The carousel revolved easily but there was a great deal of jerky motion of the horses. Two causes were found. The first was that the axles for the pinion gears had quite a lot of lateral motion due to the sloppy fit of the axles in the holes of the 21 hole strips of the driving mechanism. This allowed the pinion gears to be pulled sideways and bind on the crown gear. The second cause was the rotation of the collars on these same axles at the point where they passed through the 10-inch girders at the edge of the raised grooves, causing the collars to hesitate as they try to move out and over these grooves on every rotation. I removed the collars from the axles at the girders and attached them to the outer holes of the OG formed 21 hole strips with additional washers under the screw heads to keep the screw from contacting and freezing the axle. Passing the axles through these collars almost eliminated any lateral movement. The addition of 1/4-inch nylon spacers between the pinion gears and the inside edge of the drive mechanism’s 21 hole formed strips and pushing the axles inwards to just make contact with the nylon spacer around the drive axle now held the axles from moving in or out, keeping the pinion gears centered on the crown gear. (See photo 2) These two “modifications” eliminated the need for the collars at the girders and resulted in a fairly smooth rotational movement of the carousel and of the vertical movement of the horses.

18. **I assembled the sound effects kit and attached it to the motor. I had to steal a P15 coupling from another set as I had used the second, of the two supplied, at the top of the cone (see note 14). This coupling was necessary to add a short axle from the P-13A566B rubber coupler to reach, and attach to the motor. From left over parts I built a set of steps from three MC 1-inch x 2 1/2-inch base plates, two ME 1-inch x 4-inch base plates and the MD 2 1/2-inch x 5-inch base plate which works out well at the corner of the model base. I decided not to use the MX house because it is out of proportion and could almost be used as a hat for one of the horses.

19. ** At completion of the Merry-Go-Round only, I had 7 extra 1/4-inch x 8-32 screws and was short by three N21 nuts. 32 nuts were used on the 7/8-inch screws holding the square girders together and approximately 12 more were used as lock nuts on the moving horses and boiler. Taking into account some of my own modifications requiring additional nuts and screws and using paper brads instead of nuts and screws to mount the horses, the number of screws and nuts supplied with this set would be insufficient to have built the Merry-Go-Round and the sound effects simultaneously. Fortunately, I was able to use the additional screws and nuts needed from another set.

Jeff Schredder writes

When I was a kid building with my Erector set I didn’t like the sharp corners on the N21 nuts — I thought they were painful to work with. After I bought my 10 1/2 set from Marion Designs I discovered I didn’t like them any better as an adult. So one of the first things I did when I got interested in Erector again was to go to the hardware store and buy several boxes of 8-32 hex nuts and an 11/32-inch nut driver to tighten them with. I still use the N21s where a hex nut won’t fit, such as assembling CS wheel segments, but for general assembling I use the hex nuts.

Appropos of screws and nuts, keep in mind that 8-32 machine screws are available in many lengths besides those which Gilbert provided. Particularly useful is the 3/8-inch length, useful for putting together 3 or 4 girders.

Finally (for now anyway), many of you are aware of this but some may not be: the MB 18 1/2-inch angle girder is just the Meccano part 7A. Gilbert added this to the Erector lineup when he bought out American Meccano. So, if you need these, you can get them brand new from Meccano parts dealers such as Joel Perlin ( Also, Meccano part 7 is the same thing but longer: 24 1/2-inch, which can be used to make a super Parachute Jump or Hammerhead Crane.

Gary Higgins writes

I have a suggestion for running Erector motors using the small stub axle at the rear of the motors. This axle can be driven by a modern, 6 or 12 volt motor thus enabling the 110 volt motors to be driven at low voltage for public displays etc. It may even bring a new lease of life to worn out motors of run those safely where the mains lead is frayed or worn and saves the cost or replacing it. These small; motors are about $12.00 NZ and would be even cheaper in $US. Details of my trials with erector motors to date are online at my flickr site should your members wish to view it

Tom Myers writes

.001-.002 brass foil can be used to reduce the slop between an axle and its bearing. In may cases I have found axle wobble to be a real problem, especially when say a single BT is used and two CJ’s must mesh and track well.

Gale Wollenberg writes

Here are some of the things that I have found to enhance erector sets.

Ladder chain and sprockets can be found in obsolete copy machines–check with a copy machine repairman. Also sprocket chain and sprockets that are about half the size of bicycle chain can also found in them as well as miniature ball bearings etc.

These miniature ball bearings would be of help if you build a working model that will need to operate in a display for a number of hours. Sometimes you will find those small ball bearing stamped housings to be compatable with hole spacings on erector set parts etc. Clear scotch tape or pop can aluminum can be used to “bush up” a shaft to fit the bearing for the above. This way you will prevent hole elongation in the erector parts themselves.

Also to be found in junked copy machines are proper size cable drums, several feet of very miniature cable which works quite well on the erector pulleys, and 110 volt miniature fan motors. The shaft of the motor usually has an easily removed plastic fan blade and if the shaft isn’t quite the right diameter, a good hobby machinist can machine a small pulley wheel for it. Someone with good sheet metal cutting and filing abilities can easily make the end frames to somewhat resemble the original 1916 batery powered D.C. motor.

There is a hand punch holder at harbor freight with various sizes of punches that work quite well for punching holes in replica erector parts.

I have also found that the spray paint cans from Wal-mart make nice looking boilers when the bottom is carefully cut out and the nozzle is carefully taken out of the top. The label is cleaned off, one coat then of gray primer and then a coat of shiny black.

The more squat cans of shaving cream make nice boilers for an erector horse drawn fire engine–preferably using the 1916 stamped spoke wheels with o-rings for tires.

Dave Ware writes

To keep a string drive belt from slipping, tie the loop with it only around one pulley and around the axle of the other pulley. Put a drop of Elmers on the knot. When it is dry, trim the ends of the knot and stretch it over the pulley.

For heavier loads, use pulleys made from 2 BN Turret Plates and a BT Pierced Disk. Tie the loop slightly smaller than needed and glue the knot. Put rubber bands in the slot of the pulleys. If done right, the motor will stall before the string slips. Slightly looser will allow the drive to slip a little at the start up and shut down and serve as a sort of clutch for high inertia models.

MV Flat Car Trucks can be made by flattening P29 Car Trucks. Go easy or you will end up with 2 pieces.

NM 10-inch by 2-inch Flange Plates can be made from MN 12-inch Base Plates. This requires hack sawing them to length and clamping them between 2 pieces of wood to make the bend.

Do what Gilbert did: Make O Pawls by bending F 5 Hole Strips. (Some O Pawls have a hole at the bend and some don’t) Make NL Bolster Brackets from H 11 Hole Strips. Make NN 1-inch by 2-inch Flange Plates from ME 1-inch by 4-inch base plates (or cheaper shortened MF 1-inch by 5-inch base plates). Of course, P20 5 Hole Strip Formed, OG 21 Hole Strip Formed and NS 41 Hole Strip Formed can be made from their namesakes.

A small rubber band wrapped around an axle with a washer next to it can substitute for a P37 collar.

Washers can be used on axles to keep gears or collars from rubbing on the sides of gear boxes or other axle supports. Several of them can be used to keep a gear or pulley in place when there isn’t room for a collar.

If holes in overlapping plates don’t line up well enough to get a screw through, use an awl to align them.