453 replies to this topic

[MSwiss]

Hi Rick,

 

Yes, there is a visible difference between the 6 volt and 3 volt armature windings.  I didn't notice before.

 

I'm new to running these cars in general and racing them at different voltages in particular.

 

As far as when or if I would or will run the 3 volt armature, I guess that depends on what my local track Owner -- Mike Swiss -- is planning to do.

 

At this point I'm just trying to build at least two of these classics -- Gene Husting's and Manuel Maldonado's dragsters -- before Mike finishes building his dragstrip and the all clear is sounded.

Super-awesome job on the main rails.

 

You can run on any voltage you want, from .01- 30.0V.

 

And getting up to 36V, should be easy enough.

 

You just have to turn the knob on the fully adjustable power supply.

 

I'm guessing I'll have to figure out a way to limit access to the adjustment (some sort of clear faced, locked box?) for when I turn a scouting group, loose on it, but adults with their own cars, can do what they want.

 

I should have the wiring done , possibly yet tonight, and will most likely be running cars, hard down it, this weekend.

 

My advice, since the the 3V arms are rare, start with the 6V.

[Alan Draht]

Thanks, Mike!  

 

I'll save the 3 volt Ram armature.  It won't be installed in this car.  This car's motor will use a 6 volt armature.

[Alan Draht]

Having completed the main rails, it was time to try putting the car together in rough form to see how components fit with each other.

 

The first order of business was to fabricate the drop arm.

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[Alan Draht]

Putting the car together is like building a Swiss watch.  Everything fits together with precision.

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[Alan Draht]

I have work to do on the motor.

 

The armature in here now is temporary, installed to see how parts fit together.  The field laminations need to be ground to their final shape to optimize timing and tailor magnetic strength.

 

The car sits squarely on the test block.  Ride height is perfect and level with 1-5/16" diameter rear wheels/ tires.

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[Regis4446]

 great job Alan, thanks for sharing

[Uncle Fred]

Looking good!   Are you going to grind down the laminations? Looks like Gene ground and tapered the screwhole on the top lamination right off.

[Alan Draht]

Thanks guys!  

 

Yes, I am going to grind/ shape the field laminations to look like what Gene did to his motor.  I'm replicating Gene's car as it appears in the Rod & Custom articles as closely as possible.

 

I installed the pinion and spur gears today and the armature's spacing between bearings is tight, even by Swiss watch standards.  

[Alan Draht]

In terms of building this dragster, the day was spent dealing with small but important details.

 

One was the fact that this Ram 857 motor's field laminations and armature were harvested from a kit-built dragster built by another owner before I purchased it on eBay some years ago.

 

There was an unequal number of laminations on the top set of the motor compared with the bottom.  That may have worked with the Russkit kit frame using a series of tiny spacers, but not with this new one.

 

It was necessary to count the laminations on the top and on the bottom of this motor and compare those numbers with a stock Ram 857 motor.

 

The stock Ram 857 motor has 34 thin laminations top and bottom.

 

This project's salvaged motor had 33 laminations on the top and 32 on the bottom.  

[Alan Draht]

The unequal dimensions between the top and bottom sets of field laminations was one problem.

 

The other was the fact that there was no space or play in the armature's bearing-to-bearing width between endplates.

 

The two problems were intertwined.

 

The chassis build couldn't be considered complete until both issues were resolved.

[Alan Draht]

The first problem was solved by taking a spare thin lamination from the Pittman/Ram motor junk pile and adding it to the bottom set to even out the numbers.

 

This helped square the frame rails vertically, too, something which wasn't possible before, although the difference between the top and bottom frame widths was slight (the thickness of one thin lamination).

 

The second problem was solved by mounting the armature into the lathe's chuck and cutting about 1/64" of the core "spindle" thickness to match the 1/8" shaft diameter on the pinion gear end of the arm.  The cut was the width of the cut-off blade pictured, about 3/64" of the shaft's length.

 

These Ram armatures do not have 1/8" shafts running straight through the core laminations from end to end.

 

Hidden under the central fiber shaft insulator tube there is a 5/32" diameter "spindle" or raised section of the steel shaft that runs the length of the core laminations and wire windings.

 

This lathe work on the gear end increased space between the commutator and the bearing at the other end of the armature.

 

This provided enough space for a 0.020" spacer plus additional play for machine tolerance.  

[Alan Draht]

...

 

 

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[Alan Draht]

Once these two issues were worked out, the car's construction precision was made consistent on all levels.

 

I re-installed the motor's magnet so that its poles are aligned to correspond with a stock Ram 857 magnet's orientation when that motor is mounted in the same position as it is in this chassis. 

 

I wanted to make sure that I end up with a motor whose armature spins counter-clockwise on the pinion gear side of the chassis when the power is on.

 

In this case that means the magnet's negative pole is up, the positive pole is down.

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[Alan Draht]

The next  step is to set up a rotary table on the mill table and fabricate a gear guard out of 0.100" thick magnesium.

 

While I'm at it I may as well fabricate a gear guard for my next project, a replica of Manuel Maldonado's dragster, and ream lightening holes for a set of Weldun aluminum spur gears.

 

After that, I will swing attention back to the motor, epoxy/ balance the armature, grind/ shape the field laminations top and bottom, set up the brushes/ springs, install power wiring.

[Howie Ursaner]

Really Great !

[Alan Draht]

Thanks, Howie!  

 

I've been working on the early stages of fabricating the Husting dragster's gear guard.

 

I've decided to mill two gear guards, one for the Husting replica, and the other for the next project, replicating Manuel Maldonado's magwinder.

 

The gear guards for both cars are identical in terms of the maximum size Weldun spur gear (70T) and pinion gear (26T) that will be used by these cars in drag racing.

 

It follows that the inside and outside circumferences of both gear guards are identical.

 

So, both guards will be milled together, similar to the Husting car's main frame rails.

[Alan Draht]

First step is planning, then drawing, and finally tracing over the drawing using yellow trace paper.

 

 

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[Alan Draht]

Same as Husting's car, the gear guards will be fabricated from 0.100" thick magnesium sheet.

 

Based on the drawing and some planning on how the milling process is going to work, I cut two blanks, 2" wide x 4.5" long from 0.100" thick magnesium sheet.

 

Then I drilled, tapped and bolted the two blanks together using 2-56 bolts, one at each corner.

 

I used the mill's existing set-up of twin vises to work on the blanks during this stage of preparing to fabricate the gear guards.

 

 

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[Alan Draht]

After the blanks were bolted together, I placed them on a round Sherline 5.5" diameter aluminum tooling plate together with the drawing/ tracing to confirm how the workpiece will be positioned for attachment.

 

The tracing was used to establish how to size the magnesium blanks.  The pair of magnesium blanks are sized to fit on the round tooling plate.

 

The stacked pair of magnesium blanks will be fastened to the tooling plate as an assembly.

 

The tooling plate will be mounted to a Sherline rotary table.  The rotary table which in turn will be mounted on the milling machine's X - Y axis table. 

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[Alan Draht]

Holes for the pinion shaft and rear axle, 0.1250" diameter, have been drilled.  The center-to-center dimension is 0.7188", based on a 64 pitch 69T/ 23T 3:1 gear ratio.

 

The maximum spur gear size is 70T.  The corresponding pinion gear size is 22T.  

 

The maximum size pinion gear is 27T.  The corresponding spur gear size is 65T.

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[Alan Draht]

Layout and scribing the pattern came next.

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[Alan Draht]

A 5.5" diameter, 1/2" thick, aluminum tooling plate was prepped and a rotary table was mounted to the mill's  X - Y table.

 

The workpiece consisting of two gear guards bolted together was fastened to the tooling plate.

 

The workpiece is ready for milling.  The first cut will be made to the inside of the gear guards' spur gear edge.

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[Alan Draht]

Milling in action...

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[Alan Draht]

Gear guard work is progressing.

 

I have left a "connection" or bridge between the cut and the rest of the workpiece.  This helps keep everything aligned/locked together while milling work continues on the rest of the gear guards.

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[Alan Draht]

The gear guards' inside edge or circumference appears to just clear a 69T spur gear. 

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