What's this tool/fixture?

Could this have been some sort of bearing plate and the cross hatches are for oil passages?

David

Thought you might find the attached interesting.
Especially page 16 of Lapp Tech.
Or Chapter 2 the older Modern Tool Making text.

I was blessed with a flat lap plate several years ago. Some guy pulls into my driveway and knocks on my garage overhead door. Says he heard I did some machine type stuff and they were throwing this away at work. He wasn't real sure what it was. It's maybe 16x20. She is fun to use, that is unless you expect to see chips fly as a metric for progress.

David S might be correct.
It'd be interesting to identify how this prints.
Do you have any way to blue this up and identify flatness?

Daryl
MN

Wow. Thanks Daryl. I really liked the linked PDF. I really enjoy old shop articles and info. I looked high and low online for a pic of the lapping plate with the v. I think that must be what it is. It's cast iron. It has some deep scratches that need to be de burred befor it will blue up at all. It is definitely ground. Can a lapping plate be scraped flat? Or am I missing some part of the difference.
Thanks

Daryl,

Thank you for sharing these two publications, they are great reference materials.
Especially the one on lapping, I have not seen this kind of detail on the plate wear in other publications before.

I have two cast iron laps, one coarse and one fine grooves for small items, think like barber clipper head size.

Dean Z.