Measuring the alignment of a slide dovetail with the adjacent face.

If you want to measure the parallelism of a dovetail with the adjacent face of a slide, how do you do it?

I've got an idea for how, but I'd like to hear what others do. I'm interested in tenths level accuracy.

I'd use the search function of this site.

Actually not a bad search function, but it didn't find what I wanted to know which is aligning a female surface. Some got close, but didn't shwo enough detail to be clear. I'll try some other searches.

A dovetail is formed by two surfaces (i.e. two planes intersecting at an angle). Since it is practically impossible to use directly the line of intersection, the best method is to use a cylinder tangent to the two planes (e.g. a ground pin resting between the two surfaces of a "female dovetail" or resting between a flat surface prolonging the horizontal plane of the "male dovetail" and the inclined plane).

Paolo

i usually measure dovetail using pins or plug gages and a micrometer. a angle block and indicator sometimes used if just measuring parallel and not size
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by unscrewing rods on a magnetic base you can attach to a block or a angle piece and indicate many things. usually its 1/4-20 or M8 thread. also use a granite square and or straight edge on a surface plate. anything can be curved, wavy and or twisted. and many parts sag from their own weight. usually got to think about how it sits on a granite surface plate.
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curved and twisted parts often do that cause just clamping for machining the clamping forces can distort a part AND after machining when unclamped many parts will go bong or thunk and distort when free again. hard to describe but have seen many times.
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localized hardness variations in castings sometimes cause bumps or waves too when machining. again hard to describe but have seen many times. ductile iron although its stronger its higher strength and hardness and consistency makes machining it harder to do too. hard to describe. can easily spend more time getting things under .0004" per 40" when lightly clamped than to rough machine the part

Question needs more context to answer.

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Problem Measuring Dovetail Parallel on Compound -- Scraping in the Compound



Dovetail measuring info

matra said:

http://www.neme-s.org/Model_Engineer_Files/Gauging Dovetail Slides.pdf

Click to expand...

Matra...thanks you for this. Very valuable info.

There was another pdf about this on calculating. It disappeared. ?? Put it back on or Send that to me if you can revive it...