3D Printed stimpmeter

iusedtoberich said:
I'm also noticing for doing collision tests, the 3d printed ones are way too short. I guess that's why the Kohler ones are so tall.

I also ran into a lot of difficulty aligning the ramp perfectly normal to the cushion. Even with the wider back on v2, it still compressed the cushion and was easy to misalign a few degrees. I'm wondering if that's why Kohler was describing a direction box.
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I found that there was some inconsistency in how the ball left the ramp so it wouldn't even follow exactly the same path all the time. If it's released poorly, I think it rattles back and forth going down the ramp and ends with some small launch error.

iusedtoberich said:
What was your release mechanism Bob? I can't quite make it out. Is it a pin in front of the ball that you simply lifted straight up?
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I'm not sure. I think I used a pen to hold it against the adjustable block and then pulled it away horizontally. I used the fixture to do the no-rail rolling spot shot. The ramp has much better speed control than I do. (Shoot a standard spot shot slowly and don't hit any rail.)
 
I wonder if there is a small level area (or very near level, lets say 1 deg tilted) only where the ball is released from, if it would help consistency. I think the spin is caused by the ball running away quickly from the skin of the hand. If the ball instead walked away slowly, maybe much less/no spin would be imparted.

I haven't noticed any rattling on mine side to side on the way down. Mine uses a V-groove track. I can try a slow motion video another time and see if I notice any.
 
garczar said:
I remember that now. I can tell just by feel that some of the balls at my local spot are smaller than spec. Be cool to know how bad.
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The set of pool ball gauges that was being sold on Ebay (five different diameters) did not have small enough sizes to measure most of the pool balls in pool halls. My former home PH ran the balls through the ball cleaner (AKA grinding machine) every day. One guy brought in his shiny, new measles cue ball. It was about 2mm larger than the house ball. :eek: And of course larger than all the object balls.

I think I've seen a ball separator device. Two nearly parallel rails (rods?). Smallest separation is maybe two or three mm smaller than spec and the largest is just above spec. Where the balls fall through tells you how big they are. This would give you a chance to make matched sets from a bunch of mixed up sets.
 
iusedtoberich said:
Yeah, agree. I don't know that it would have any practical use:)
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It has plenty of use, if you work on or play on different tables. Once you work out a few standard measurements for a "normal" set of tables you can compare them exactly instead of "this table feels slow" or "that rails seems off a bit", you will have actual numbers. You can measure with consistency exactly how the cloth rolls, how the rails rebound, if there is a roll off without taking the stroke or spin into account of the shot, really quite good data to be gleaned from using it. Similar to the table difficulty calculations, set a standard we are comfortable with using, then compare things against it.

I do agree the slope needs to be less, more like a triangle, and we should maybe even contact the table manufacturers and cloth makers to see if they use similar tools. It won't be much good to measure a distance if one person is using a 15% slope and another one is using a 30% slope.
 
iusedtoberich said:
I designed and 3D printed a stimpmeter. This is the first one. It needs a few improvements but its a good start.

View attachment 720834



16 second video of it in action:

The second one will look like this. A wider base (first one was difficult to hold straight to the rail). More clearance for the ball in the front so it transitions smoothly onto the cloth. Pointers on the front and back if you wanted to align it to a line drawn on the cloth. A bit taller and longer than V1.
View attachment 720835

View attachment 720837

Version 3 I'll probably add some stops so so the ball can be dropped from different heights reliably. I might also change it to a straight top instead of an arched top. It was difficult to hold the ball against the end at the exact spot, I think due to the sharp upward angle. That would require a longer ramp which may not fit on my printer. I may also add a cradle to hold an iPhone from the side for slow-motion recording, and lines on the side to measure how far the ball bounces back up the ramp when placed against a cushion. A cushion testing version would also need to register the front of the ramp against the cushion nose. (the slow motion video V1 is too high).
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That's pretty cool
 
kling&allen said:
That’s a steep curve and I bet your testing will show the ball rattles and jumps as it comes down and hits the cloth. You might want to investigate a smaller slope. I think a target 10 foot roll (so you can measure bounce off the end rail) is idea for a 9 foot table. I use one with a 8 foot roll for the 7 footers I play on (8 feet being what I get on a diamond with 860 and old cloth on a winter day). My home table is like 7.5 feet.
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where did you get yours?
 
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Version 3 is on the printer. Improvements I made today: register on the front and rear shaped like a ball, so it contacts the rail the same way across different tables. (A straight wall would not with varying cushion heights/radii on different tables). Register to the rail is much wider, to help with the rocking issue it had before. Ramp is straight now, and shorter height. Holder for a phone to record in slow motion. Holder for 6" ruler to use with phone. I want to put a release mechanism and stop for the CB, but ran out of time. This is the biggest I can make it on my printer and keep it one piece. Hopefully it does not warp much in the printer.

Heading to a scratch tournament now. This will be finished when I get home. If I go play pool tomorrow, I'll take it and test it.
 
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Version 3 is off the printer. It did warp a bit on the bottom, but I don't think enough to affect function.

1720042531479.png

I tried it with a 3D printed ball against a wall (did not go to pool hall yet). This is a still from the slow motion video. It's easy to pick up the right edge of the ball at 2.5 inches in this case. There is plenty of frames per second with the iPhone to do it. I had the camera in a different position than the slot to get the height better, so I'll probably need to adjust the phone holder.
 
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I designed a release and a stop built into one today. It's on the printer now. I had to make it work with the existing ramp since the ramp was already printed. I'll integrate it better when I print the ramp again after testing the whole system and seeing what needs to be improved.


1720042945404.png

It's simple, just a pivot. Hold it down against the hard stop and it will hold the ball up.


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Let go of finger, and the ball will run it over and head down the ramp.

There might be a way to also turn this into a pointer when the ball bounces back up the ramp, eliminating the need for the camera. But that is a lot more design effort.

I'll be heading out tomorrow and will be able to test the whole system.
 
i havent read all the posts
but
cant you just put 2 shafts side by side
put them on the rail and roll the ball to see how far it rolls?
keeping where on the shafts you use so the "ramp" stays the same length
couldnt take a pic with the cue ball on the shafts alone because it wanted to roll
you guys are smart enough to get the idea....:)
stimp 1.jpg
stimp 2.jpg
 
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