Key seat dimensions from an odd callout.

[Bradley.linsmeye]

I have a print that calls for a 1x 1/2 standard keyseat. What is the actual keyseat depth for a callout like that, I dont see anything in the machinery handbook for keyseat called out that way.

Thanks in advanced

 

[dandrummerman21]

I have a print that calls for a 1x 1/2 standard keyseat. What is the actual keyseat depth for a callout like that, I dont see anything in the machinery handbook for keyseat called out that way.

Thanks in advanced

There isn't enough information you've given. is there a drawing? Does the drawing show the keyway?

I am *assuming* it isn't a woodruff keyway.

I am *assuming* they want a 1/2" square key, 1 inch long. But there are other ways to interpret it. The key *could* be rectangular and not square, although I don't see a 1/2 x 1 rectangular key anywhere. Seems that standard rectangular keys include 1/2 x 3/4 or 3/4 x 1". So I think you're looking at a square 1/2" key.


So, assuming it's a 1/2" square key they intend to use, you would need to know the diameter of the shaft you're putting it on.

In my 25th edition book I have handy with me here, page 2262 "Keys and keyseats, table 8, finding depth of keyseat and distance from top of key to bottom of shaft" gives you a bunch of diameters, keyway widths, and a formula to figure out how deep to go. It is worth noting that keyway depth is called from the sharp corners created by the keyway, so you'd be 1/4" deep plus the distance from the top of the shaft to the chord created by the sharp corners. This table will give you that dimension.

On the page preceding it, ansi standard fits for parallel and taper keys, it says you get +0 and -.015 tolerance on depth. meaning you can be up to .015 deeper from the top.



When in doubt, could always ask the customer what size key they are using.

 

[Mtndew]

When we do keyways, and there isn't a tolerance or specified dimension to cut it to, we always take the chord height into consideration then go 1/2" deep.

For instance, a 1" x 1/2" keyway on a 5" diameter shaft I would go .5505 deep from touch, making it 1/2" deep on the wall.

 

[Bradley.linsmeye]

There isn't enough information you've given. is there a drawing? Does the drawing show the keyway?

I am *assuming* it isn't a woodruff keyway.

I am *assuming* they want a 1/2" square key, 1 inch long. But there are other ways to interpret it. The key *could* be rectangular and not square, although I don't see a 1/2 x 1 rectangular key anywhere. Seems that standard rectangular keys include 1/2 x 3/4 or 3/4 x 1". So I think you're looking at a square 1/2" key.


So, assuming it's a 1/2" square key they intend to use, you would need to know the diameter of the shaft you're putting it on.

In my 25th edition book I have handy with me here, page 2262 "Keys and keyseats, table 8, finding depth of keyseat and distance from top of key to bottom of shaft" gives you a bunch of diameters, keyway widths, and a formula to figure out how deep to go. It is worth noting that keyway depth is called from the sharp corners created by the keyway, so you'd be 1/4" deep plus the distance from the top of the shaft to the chord created by the sharp corners. This table will give you that dimension.

On the page preceding it, ansi standard fits for parallel and taper keys, it says you get +0 and -.015 tolerance on depth. meaning you can be up to .015 deeper from the top.



When in doubt, could always ask the customer what size key they are using.

I did ask because it was 17 inches long, so I know the width is 1 inch wide and im guessing the depth is as mtndew has stated for the 1/2 depth on the wall. But it didn't call out a sled runner radius so I figured I'd just go to the source.

Thanks guys!

 

[guythatbrews]

When in doubt, could always ask the customer what size key they are using.

Always the best solution. Unfortunately the customer is not always responsive. How I value a quick and knowledgable customer response! Funny how it seems responsive customers are always the best customers.

The other not so good guys may resond with, ignorance, sloth, anger, seen it all. The worst one was an ammo plant run by the army. They were sourcing replacement parts for ammo-making machines with drawings from the 30's. Lot's of material that was no longer produced or at least no longer produced under the name on the drawing. They would not suggest a modern alternative. No way to quote that job!

 

[Winsten]

FWIW my day-gig job shop supervisor sometimes refers to key seats as width x depth… I realize this may just muddy the water for you

A “1 x 1/2 key seat” is a slot for a 1”x1” key by that terminology… this kind of mix up is why they keep me around- a decent drawing answers a dozen questions. Mine typically answer at least 6.