In this e-mail from Don Yost (below), I became aware of homemade dynamics ramps that Malcolm Wells had his Modeling Workshop participants make, in his six-week summer workshop at Arizona State University in summer 1991. Don Yost was there. He gave me a sketch and the specs (on accompanying jpg).
From: Don Yost, Sacramento, CA
Date: Wed, 15 Mar 2000
Subject: board
To:
Éif you were doing "explosions", acceleration, and force experiments, you could get by easier with the ramp plans used in 1991, using plastic laminate instead of bare pressed board. They were light, they nested, they were flat, and they had very low friction.
Feb. 13, 2002
From: Brian Bingham, Deer Valley High School, Deer Valley AZ.
At Jane Jackson's urging, I'm adding this post to describe my
experience building tracks for dynamics carts. Jane supplied me
with some plans that Malcolm Wells had worked up some time ago,
and I basically went on from there.
First, realize that although I have a garage and a few basic power
tools, I am not Norm Abrams. Building 8 tracks (6 are 60" long, 2
are 48" long) took me about 40 hours of inefficient carpentry and
cost just under $100 in materials. The tracks have worked very well.
I did modify Dr. Wells' plans in some details. I added furniture feet
at one end, and at the other end I installed threaded inserts that
accept common 1/4" bolts that my students swap out to use as
leveling feet or elevating feet as required. I also added a pair of
rubber furniture tips screwed in to the surface to act as bumper
stops at one end of the track.
I've sent Jane some photographs of the tracks which she has
promised to put up on the modeling web site. I do plan one more
modification - something down the center to serve as a guide for the
carts to facilitate collisions. I'm contemplating gluing on some
Formica.
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Date: Wed, 13 Feb 2002
From: John Barrer <>
Another alternative is to buy extruded vinyl gasketing for the sides of garage doors. You'll need two; they have a series of semicircular grooves. You need to inspect closely, as some grooves have bumps and other imperfections. Put them side-by-side with a large paper clip in between for proper spacing. They work well and are only about $5 each. John Barrere
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Date: Thu, 14 Feb 2002
From:
I built some of the "Malcolm" tracks in 1991, and they have held up over the last 11 years. I used the school shop after hours, and it didn't take very
long because they are set up for cutting long materials. I don't know if I
noted when I dug up the plans for Jane that I used particle board that was coated with white plastic on one side. It provided a much smoother surface, wore better, and was far cleaner. If that comment is not on the plans, it should be.
I used thread and eye bolts screwed into the carts for the two-cart collision to keep them on target.
Sounds like you had a positive experience with them. I found there was less friction on these tracks than with the Pasco tracks. Something about the
grooves seems to scrub some speed.
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Feb. 13, 2002
From: Brian Bingham:
Here's some more of the "nuts and bolts." This information could accompany the pictures on the web site.
1. The coated particle board is VERY HEAVY. All of the major home improvement stores will cut these materials for you for a nominal fee if you're willing to stand around waiting and be humble enough. I mentioned that I was a teacher and was building equipment for the lab and the Home Depot employee only charged me for two cuts instead of 9 cuts required. The board actually yields 6 - 60" x 8" and 4 - 49" x 8" pieces that can be made into 10 tracks, but I only built 8 and used the remaining material for another purpose. The 4 smaller boards are 49", not 48", because this material comes in a 96" x 49" size for some reason.
2. As in Malcolm Wells' plans, the boards along the sides have to be rabbeted. I did this on a primitive table saw without any special blades, and managed all right, but it took some calculations and I wasted some wood. I used 1 x 4 pine, rabbeted two edges, and then ripped them up the middle. I attached them to the particle board with screws AND glue. Whether you use screws or nails, be sure and drill pilot holes to avoid splintering off huge chunks of your tracks.
3. I did not paint or otherwise finish any of the wood, since it won't be exposed to water or weather. I did lightly sand the pine side rails to eliminate splinters and to round off the sharp corners.
4. I added the following hardware:
At one end, I added swivel feet (nailed into the pine rails). I used:
Shepherd Hardware Products # 89098, 1" nail-on swivel guides (Home Depot)
On the same end but at the top (2" from the end and 2 1/4" in from the side rails) I attached two rubber furniture tips (open end up) using wood screws to act as bumpers.
Shepherd Hardware Products # 89125, 5/8" rubber tips (Home Depot)
Finally, I installed threaded inserts at the opposite end, 1 1/8" from the end and 7/8" in from the side rails, to accommodate 1/4" bolts that enter from the bottom and can either level the track or elevate that end. I purchased a pile of inexpensive bolts ranging from 2" to 6". If you buy carriage bolts, they are threaded all the way up. I used:
Crown Bolt Company, DR #552, threaded insert wood thread hex, 1/4" x .295-.343"
(those weird numbers and description come right off the package).
For the inserts, you drill a hole and thread the insert in using an Allen wrench. Then you have metal threads that won't wear out.
Once you have the basic tracks, use your imagination to attach or position photogates, motion detectors, pulleys, and so on. I've used them for all the mechanics labs requiring the dynamics carts, and have had good results. Enjoy!
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Feb. 21, 2002
From: Jeff Simpson, formerly of North Canyon HS in Phoenix, AZ:
I took pictures of Brian Bingham's home-made tracks É
[JaneÕs note: the six pictures are included here.]