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Old March 31st, 2017, 11:22 PM   #41
fierocious1
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Let me take a look at them.

Side not: I'm skating Saturday, so I can't meet this weekend.

I thought the best plate to modify would be the magnums. However I don't think there is enough meat in the plate once I mill out space for the second cushion.


Update on project: I was worried that I modeled parts correctly so I compared it to my Royals. In the model I set my kingpin angle at 60 deg. and updated the pivot position to match the actual hardware. I then held up the plate to my monitor to see if the profiles matched. (This is the super-scientific way of doing things) But it looks really close.

The most I can rotate the truck assembly is 5 degree. At that position the axle is directly under the pivot pin. That gives me an angle of rotation of 50 degrees. I wanted a little more. So I am considering the Advantage truck.
I cut enough out that I was able to use stacked cones with no issues. Skated those for about a year or so. Also drilled through the plate for mounting the boot on the front. Used a spacer on the back. Ill take a look at the tonight to see just how I did the rear mount.
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Old March 31st, 2017, 11:23 PM   #42
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Why longer cushions?:

I have noticed the standard cushions bottom out at the end of the stroke. Some may like this behavior as it can feel stable, especially at high speed. However I want a linear relationship in force/displacement throughout the stroke. Going to longer spring will allow more travel before experiencing the bottoming-out effect.
That was my goal!
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Old April 1st, 2017, 03:06 AM   #43
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Option using Snyder Advantage trucks.

I have to decrease the length of the bottom cushion. Showing SG cone.

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Old April 1st, 2017, 03:18 AM   #44
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Option using Snyder Advantage trucks.

I have to decrease the length of the bottom cushion. Showing SG cone.

I forgot to mention, I don't use locknuts on the KPs. I use red locktite. This allows me to keep strength in the plate by leaving a thicker area between KP and the pivot cup. Looks steep on the caster, but you never know til you skate them.
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Old April 1st, 2017, 04:00 AM   #45
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I forgot to mention, I don't use locknuts on the KPs. I use red locktite. This allows me to keep strength in the plate by leaving a thicker area between KP and the pivot cup. Looks steep on the caster, but you never know til you skate them.
I did the same thing on my current skate setup. Only way I could fit 2 cushions. It works well, but to remove the kingpin I need to clamp down on it with vice grips. This leaves unfavorable indentions in the steel.

Actually, reducing the nut height is a good way to reduce deck height. I'll work on it.
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Old April 1st, 2017, 06:34 AM   #46
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I did the same thing on my current skate setup. Only way I could fit 2 cushions. It works well, but to remove the kingpin I need to clamp down on it with vice grips. This leaves unfavorable indentions in the steel.

Actually, reducing the nut height is a good way to reduce deck height. I'll work on it.
For future use, red Loctite eases its grip with a little bit of heat. And, you could use two nuts on the threads (tightened against each other) to spin out the kingpin without marring it with Vise Grips.
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Old April 1st, 2017, 10:21 PM   #47
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Originally Posted by amohrfeld View Post
I did the same thing on my current skate setup. Only way I could fit 2 cushions. It works well, but to remove the kingpin I need to clamp down on it with vice grips. This leaves unfavorable indentions in the steel.

Actually, reducing the nut height is a good way to reduce deck height. I'll work on it.
I know you are rotating the entire assy to change you caster. I did not on my setup, I just played with the cushion height only. It takes only a small amount on a shorter frame and more on a longer frame... just fyi.
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Old April 2nd, 2017, 04:22 PM   #48
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I was having issues with the geometry and thought my truck dimension were not correct. So I set up the probe and pulled dimensions for cushion center to axle. the model was off be about .035". This actually changed the angle of rotation. I'm trying to duplicate the Royal truck geometry for a good start point. I assumed the rotation angle on the Royal is close to 45 degrees. So that needs to be sorted out next.

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Old April 2nd, 2017, 04:25 PM   #49
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I know you are rotating the entire assy to change you caster. I did not on my setup, I just played with the cushion height only. It takes only a small amount on a shorter frame and more on a longer frame... just fyi.
Testing with shims is inevitable. But I'm trying to avoid shimming as much ad possible. I would like to get an evenly distributed load on the cushions during pre-compression.
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Old April 2nd, 2017, 05:42 PM   #50
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For future use, red Loctite eases its grip with a little bit of heat. And, you could use two nuts on the threads (tightened against each other) to spin out the kingpin without marring it with Vise Grips.
Thanks. I have not tried the heat gun.
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Old April 2nd, 2017, 06:49 PM   #51
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Thanks. I have not tried the heat gun.
If you have a bolt that is red locktited, usually we heat the bolt up with a small torch, but not enough to color it. The locktite will melt and the bolt will come out without heating the aluminum. Had to take some parts apart at work Thursday the same way.
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Old April 2nd, 2017, 06:55 PM   #52
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Testing with shims is inevitable. But I'm trying to avoid shimming as much ad possible. I would like to get an evenly distributed load on the cushions during pre-compression.
With the cool machinery and your background, you won't need any shims...
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Old April 3rd, 2017, 02:45 AM   #53
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With the cool machinery and your background, you won't need any shims...
Assuming I get the dimensions right to start with.

Looks like there are two reasons the dimensions were not adding up:
1. The roll angle is actually 42 degree. Its not a true 45 degree like I originally thought.
2. I grabbed a new rubber cushion to do the measurements. Big mistake. The urethane is .065" thicker.

At this point I think the model is within .015" of the real thing. But the true test is after machining.

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Old April 3rd, 2017, 12:24 PM   #54
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Assuming I get the dimensions right to start with.

Looks like there are two reasons the dimensions were not adding up:
1. The roll angle is actually 42 degree. Its not a true 45 degree like I originally thought.
2. I grabbed a new rubber cushion to do the measurements. Big mistake. The urethane is .065" thicker.

At this point I think the model is within .015" of the real thing. But the true test is after machining.

I have found most cushions will eventually return almost to original size and shape after removal and resting. It IMO also depends on how much they were crushed while in use. I don't think the used cushion would perform the same as a new one if reinstalled as it most likely has taken a permanent "set". I usually replace softer cushions every year.
When I used the test skates the "finished" dimensions could be measured after a couple of months of skating to get all the components to their final settings and dimensions. Then I could machine to a shim less frame dimension.
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Old April 5th, 2017, 12:51 AM   #55
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Interesting project. I'm wondering if there is an outside the box method to build skates that give maximum maneuverability, but without a traditional kingpin with cushions, and pivot. I mean, something radical, that allows you to lean, and the two axles pivot, but not relying on soft cushions. Maybe gears, or whatever a 4 wheel steering car uses. What can most efficiently generate an axle pivot, when a lean is actuated near it? I bet there is something that has never been tried.
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Old April 5th, 2017, 01:29 AM   #56
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Interesting project. I'm wondering if there is an outside the box method to build skates that give maximum maneuverability, but without a traditional kingpin with cushions, and pivot. I mean, something radical, that allows you to lean, and the two axles pivot, but not relying on soft cushions. Maybe gears, or whatever a 4 wheel steering car uses. What can most efficiently generate an axle pivot, when a lean is actuated near it? I bet there is something that has never been tried.
Keeping it simple is also key to keeping it light weight. Surely there is something that hasn't been tried but figuring out what that is, is what everyone is looking for.
Input/output is what makes the quads special. Being able to make them do what you want them to do is where tuning comes into play. Thats where the cat and mouse game is at, chasing the sweet spot until your skates move as you do.
Quads are special that way.
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Old April 5th, 2017, 01:31 AM   #57
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Interesting project. I'm wondering if there is an outside the box method to build skates that give maximum maneuverability, but without a traditional kingpin with cushions, and pivot. I mean, something radical, that allows you to lean, and the two axles pivot, but not relying on soft cushions. Maybe gears, or whatever a 4 wheel steering car uses. What can most efficiently generate an axle pivot, when a lean is actuated near it? I bet there is something that has never been tried.
Way back in the day I remember a plate called Microstar which had a unique action to it. I don't think it relied on cushions at all. Maybe DocSk8 has heard of it and knows more about it.
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Old April 5th, 2017, 03:26 AM   #58
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So after doing a little math and some more pondering I determined it's a bad idea to rotate the truck from the original geometry (Remember I was trying to rotate it to get a steeper angle of rotation. But doing so puts the pivot pin perpendicular to the plate.).:

The problem involves energy transfer when landing a jump.
As long as the pivot pin is at an angle to the vertical, when a force is applied at the wheels, the truck will rotate about the pivot ball and compress the cushion. If I move the pivot pin to vertical; all the force is transferred into the rigid plate. The cushions will take none of the load. This sounds like a sure way to bend an axle.

I'm going to increase the rotation angle another way:
1. extend the pivot pin. Looks like I need to make the pivot pin .200" to .250" longer. So it's going to be a custom part. - There goes my low cost goal.
2. Add a washer(s) to shim between the truck and the bottom cushion.
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Old April 5th, 2017, 03:52 AM   #59
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Way back in the day I remember a plate called Microstar which had a unique action to it. I don't think it relied on cushions at all. Maybe DocSk8 has heard of it and knows more about it.
Funny, I was thinking about that plate yesterday.

I've seen it mentioned a few times. It did use cushions on the side for steering. But they don't support the skater's weight like the conventional geometry.

http://www.skatelogforum.com/forums/...ead.php?t=3101

Best I can tell, The functionality is similar to the modern Arius.

It has some advantages and some disadvantages, but it still uses a rotation angle similar to the conventional skate. So I can't imagine huge performance gains.
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Old April 5th, 2017, 04:04 AM   #60
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Interesting project. I'm wondering if there is an outside the box method to build skates that give maximum maneuverability, but without a traditional kingpin with cushions, and pivot. I mean, something radical, that allows you to lean, and the two axles pivot, but not relying on soft cushions. Maybe gears, or whatever a 4 wheel steering car uses. What can most efficiently generate an axle pivot, when a lean is actuated near it? I bet there is something that has never been tried.
To be honest, I think it's impossible. Which makes the idea even more fun to think about. My latest thought is a conventional truck for the rear wheels and crossing tie rods from rear axle to front axle. This will allow use of a vertical pivot for front wheel steering. The major advantage is the elimination of the caster issue in the front wheels. Of course if you skate backwards you might be even worse off.

But I do have some other thoughts I want to lay out in the cad system sometime. Unfortunately work and life has me really busy these days.
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