Hi Guy
Since I have neither a surface plate, nor a machine shop, mills , lathes or a drill press. I don't have much need of the accuracy that can be had from a lab quality plate and Johnson blocks.
A good straight edge would be enough to tell me if a head was warped. I don't have a good straight edge either. I do know how to make one if the need comes up.
We are talking about how to do things in the "How to" section?
If you want a short course on how to make a straight edge or a flat plate I can oblige.
Some of us don't have the $ to purchase the best tools for our shops. I thought to suggest a small $ alternative for those of us who would like to do a job without spending a lot of $$$$#!
Thanks
Dennis
"Lab quality"? nope.
The point of a surface plate is that it gives you a datum. (
http://www.m-w.com/dictionary/datum)
Once you have a datum you can measure, and measuring tools are cheap, especially second hand.
Before you go anywhere near a machine shop, mill or lathe you need a reason to go there, and that reason will either be because something is not as it should be, or because you want to modify something, either way you need to measure first.
Don't make this an argument / discussion about cheap tools, because it isn't.
By definition you CANNOT make a surface plate or straight edge, without using something known to be straight or flat as a reference.
You can make a pretty good flat surface or straight edge sure enough, but there is something you MUST understand about engineering.
"very small inaccuracy" might be used to describe something, such as the flatnesss and uniformity of a home made surface plate.
the non-engineer will interpret "very small inaccuracy" as a good thing, eg closely approaching accuracy.
the engineer will interpret "very small inaccuracy" correctly, as small but significant and unknown level of inaccuracy GUARANTEED IN EVERY MEASUREMENT"
eg GUARANTEED INACCURATE
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There is a thread elsewhere about rocker wear and geometry.
Rocker are levers, and levers multiply errors.
Without a PROPER surface plate and a PROPER engineers right angle, you, BY DEFINITION, have no way of ascertaining if either your valves or your rockers are operating in a vertical plane, and until and unless you can guarantee this, and rectify it if required, you have precisely ZERO chance of setting them up in the vertical plane correctly.
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wherever you are in the states, keep you eyes open and for 200 bucks you can pick up a good used surface plate, same again will get you a set of good used vee blocks, mic, dial, vernier and a couple of angles.
if you don't buy these tools and learn to use them, your machinist will have no option but to use his, and all he will be able to measure are the bits you hand him and your drawings, not the bits you keep at home, and he will charge you his hourly rate for this measuring.
want to know if your piston is of uniform height and if the ring grooves are cut square, want to know if your rods are straight, want to know if your valves are the right length and straight, want to know if your rocker geometry is right, want to know if your barrel is the correct length, etc etc etc etc? then you need a *proper* surface plate, or, like me, access to one in your local machine shop