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Discussion Starter · #1 ·
I just restored an old Craftsman benchtop jointer. This is no lightweight jointer with a plastic case and aluminum tables and fence. On this Craftsman jointer, the case, tables, and fence are all solid cast iron. It weighs close to 70 pounds. That's too heavy and awkward for me to store on the floor and lift onto a workbench by myself day after day. It needs to go on a stand.

My original plans followed the outline of the case - 11 x 19 inches. I would like the jointer bed to be 34-1/2 inches high, to match the table saw. That means the stand must be 26-3/4 inches tall.

The problem is that 70 pounds up that high on a narrow 11 x 19 inch stand seems too tippy. I am concerned that the jointer would get knocked over too easily. Obviously I need a wider stand. That said, I need the stand to be as narrow as possible to fit in our already tight storage space, but the highest priority is that it must be stable.

-> Here are my questions:
Is there a designers' rule of thumb for computing the bottom width of a base based on the height and weight (mass) of the center of gravity to achieve reasonable stability? Do they design with a minimum angle from the center of gravity to the edge of the base?


Related: How do industrial designers define "stable enough"? Do they look at the force (torque) required to knock something over? - How much force? ... or Do they look at the angles only?


Additional info (can be ignored):
The current paper design is very simple and boxy. It has four posts with upper aprons and lower stretchers. My intent was to extend the lower stretchers beyond the posts to attach two fixed casters on that end. The stand would rest solidly on the posts, but when you lift up, the casters touch and it rolls like a wheelbarrow. That is on hold until I can figure out the width of the stand's base.
 

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where's my table saw?
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where's my table saw?
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What are the dimensions (L, W, H) of your stand? I am especially interested in width and height.
I donno? I gave the whole setup to a buddy of mine. He gave it to his brother. It's now gone.
None of the dimension were critical, I winged it.
The width was a bit excessive, probably around 15 "- 16".
The height would be user dependent. I think my shop machines are 34" to 35" tall.
The two cabinets on the ends were identical with open ends and provide tons of storage. The section in the middle was wide enough for the motor and tall enough to be practical. The belt just slips on and off if need be. You hang the motor by the belt leaving 3/4" space or so and make the shelf at that height. When you tighten down the motor, it also tightens down the belt.
 

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Discussion Starter · #5 ·
Thanks for the info and the photos.

What I really need to know is:
Is there a designers' rule of thumb for the angle between the center of gravity and the closest edge of the bottom base for "stability"?
 

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where's my table saw?
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Thanks for the info and the photos.

What I really need to know is:
Is there a designers' rule of thumb for the angle between the center of gravity and the closest edge of the bottom base for "stability"?
Yes, tall skinny things "fall over" shovels, brooms etc.
Narrow, top heavy machines "tip over" jointers, bandsaws, etc.
Murphy's law and Gravity are forces to consider.
Do not put "trip hazard" legs sticking out out from the base. Your base is better flush down to the floor.
 

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i had a smaller delta rockwell homecraft jointer for a long time
i actually anchored it to the concrete floor next to my table saw
it never moved or got tippy again
 

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mike44
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I just restored an old Craftsman benchtop jointer. This is no lightweight jointer with a plastic case and aluminum tables and fence. On this Craftsman jointer, the case, tables, and fence are all solid cast iron. It weighs close to 70 pounds. That's too heavy and awkward for me to store on the floor and lift onto a workbench by myself day after day. It needs to go on a stand.

My original plans followed the outline of the case - 11 x 19 inches. I would like the jointer bed to be 34-1/2 inches high, to match the table saw. That means the stand must be 26-3/4 inches tall.

The problem is that 70 pounds up that high on a narrow 11 x 19 inch stand seems too tippy. I am concerned that the jointer would get knocked over too easily. Obviously I need a wider stand. That said, I need the stand to be as narrow as possible to fit in our already tight storage space, but the highest priority is that it must be stable.

-> Here are my questions:
Is there a designers' rule of thumb for computing the bottom width of a base based on the height and weight (mass) of the center of gravity to achieve reasonable stability? Do they design with a minimum angle from the center of gravity to the edge of the base?


Related: How do industrial designers define "stable enough"? Do they look at the force (torque) required to knock something over? - How much force? ... or Do they look at the angles only?


Additional info (can be ignored):
The current paper design is very simple and boxy. It has four posts with upper aprons and lower stretchers. My intent was to extend the lower stretchers beyond the posts to attach two fixed casters on that end. The stand would rest solidly on the posts, but when you lift up, the casters touch and it rolls like a wheelbarrow. That is on hold until I can figure out the width of the stand's base.
The 11" is the width . Make the bench top 11" or so and taper the sides so it measures about 18" at the bottom. The 19" length can be straight down or also tapered if you want. Then the total length of the bottom will be 28".
This designed to be about 1-1/2 times each dimension.
Each long side will be 19" at the top , 28" at the bottom. The short sides will be 11" at the top and 18" at the bottom.
I did not figure in the panel thickness, really does not make much of a difference. If you use 3/4" stock then if you want change the 19" to 17-1/2" and the 28" to 26-1/2".
mike
 

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My belt/disc sander and drum sander both have stands with splayed legs.

It doesn't take that much splay to add a lot of stability. Something to consider. :)
 
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