# Sled Weights - weight variations

I like to re-use things if at all possible. I have two salvaged bricks that are similar in size but no exactly the same weight. Is this a problem?

Hi there, I see no reason why that should be an issue. I like re-use as well.
A far as I see it we have different brick weights all over the world and perhaps even within US.
You can safely go ahead. A certain weight for bricks has not been published from my knowledge.

The approximate sled weight should not be over 40lbs with the Router.

We donāt have a standard ābrickā . , Iām not sure there is a brick standard due to the fact production predates publishing Iām pretty sure, originally would have been stones with no uniform weight or size.

Thank you

I agree with @Gero. The triangular linkages should be pretty forgiving about imbalance.

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Oh, I miss read the question. With 2 angled bricks of different weight you still can balance by pushing the heavier more in and the lighter more out.

https://www.astm.org/Standards/C62.htm

You could always chip a bit off of the larger brick to get them closer in weight.

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Well, the great thing about standards is that there are so many to choose from . And stocking of each seems to be iffy (and where they are located in Home Depot makes no sense):
Firebrick - Light weight, not in stock at HD, several weights/insulations
Red Brick, no holes - Located in Lawn and garden.
Red Brick, holes - Located in construction supplies
Concrete brick - Location determined by how āfancyā it is. Lots of different sizesā¦

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A chip off the old brick? Ducks

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All of that goes on your permanent recordā¦

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Itās so long nobodyāll notice

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Quack !..

Thank you

Just to confirm, in the triangular kinematics math does one even need to find the CoG of the sled? I believe that is the case meaning that it should be very forgiving, as you said.

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I donāt see the CoG value used in the triangular Kinematics calculations, so I think itās not needed with the triangular linkages. I havenāt updated it for the recent triangular linkage sleds Iāve made, and I donāt think it has mattered.

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This is correct, the sled CoG is not used in the triangular kinematics as it is assumed the linkage kit can correct for changes in orientation of the sled.

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no, you do not need to find the CG of the sled as it was asked for previously

you should figure out where the CG of the sled along the Z axis is, and position
things so that the chains are at, or just above this leve.

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With a triangular linkage the chains should be above this level to help keep the linkage from rotating to its limits. The triangular linkages work best when they are not āagainst the stopsā.

I am talking about in the Z direction, you are talking about in the x/y
direction. This gets confusing because Y is far more towards the sky than Z is.

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So if a person had some lead weight laying around and no bricks, would it be better to center the weight directly below the router? Or split it in two and spread it out like the bricks?

Some routers offer a dust collection port, if yours does then splitting the weight to leave access to the dust port makes sense.