Tolerance indications

Quick question regarding machining tolerances...

I need to indicate dimensional tolerance on a drawing. A fork with 1.130 inside dim.

the tolerance is -0, +(what)?

Non critical precision.

.005? .010?

Reply to
CaveLamb
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The larger the tolerance, the cheaper it would cost to make, but really depends on the application & how much slop would cause problems.

Can you describe in more detail? .010 thou may not be enough if whatever metal (?) it is made from has a high expansion rate, or may be too much for some parts, noise, hammering effects, etc...

MikeB

Reply to
BQ340

If I remember correctly , unless otherwise indicated tolerances on Aerospace dwg are +/- .030. Since one side is -0, reasonable tolerance would be + .060.

Dan

Reply to
dcaster

Well Don Foreman was talking about needing some direction in his life. And he has posted pictures of things he has made that looked nice to me.

What is the gooseneck fitting made of? Could a bushing be made that would restore the hole to the right size?

Dan

Reply to
dcaster

Lamb

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That's way beyond my chop saw and file technology, of course.

It's 304 stainless. There is no room inside the fork for anything, and there are sometimes pretty hard bump loads, but basically it's a pin in fork.

The wear is strangely asymmetrical. The top hole is still nearly round, although worn a bit larger, the bottom hole is nearly slotted forward (toward the mast).

We have 55 boats in the association. A few of the other southern boats have turned up a similar condition. Northern boats spend more time out on the hard with the rig down, so they see less wear. We may find enough demand in a few months to have a reasonable run made. But for now, it's just mine I'm concerned aout.

I drew it up this morning to show the local machine shop. But they close about the time I crawl out of bed... :( I'll have to rise and shine a bit earlier.

The bushing idea, though... The fingers are about .080 thick with a 1/4" hole.

I wonder how long JB Weld would last.

Reply to
CaveLamb

Quick question regarding machining tolerances...

I need to indicate dimensional tolerance on a drawing. A fork with 1.130 inside dim.

the tolerance is -0, +(what)?

Non critical precision.

.005? .010?

Reply to
Tom Gardner

Really??? That seems awfully sloppy to me.

On submarines, for anything less than 6", a three place decimal is +/- .005" Two place decimal is +/- .010" Fractional dimensions are +/- 1/64"

For dimensions 6" to 24" three place decimal is +/- .010" two place decimal is +/- .015" (or .020" ?) fraction is +/- 1/32"

Don't recall standard tolerances for dimensions over 24".

On aircraft, I mostly worked landing gear, which was generally a total tolerance of .0011" to .0015" for bearing journals in the range of 1-1/2" to 3-1/2". Barrels in the 4 to 10" range had a total tolerance of around .003"

I didn't work much to "standard" tolerances there so have NO recollection what they might have been. I *think* they were comparable to the subs.

Reply to
Steve Ackman

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When I was a paper & pencil draftsman the title block tolerance was

0.005" for three places, 0.020 for two, unless otherwise specified. I think they applied for aerospace parts at MITRE, though there I usually drew my own title blocks on the CAD system and negotiated tolerances with the vendor, to get as much as I could without paying extra.

jsw

Reply to
Jim Wilkins

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