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In this question I asked about tolerances for straight edges. For this I have a followup question about length.

If I want to purchase a straight edge, I only want to purchase one straight edge which would cover most use cases (hopefully 90+% of all use cases). This should be able to cover deck surfaces and heads for most I4, H4, V6, H6, & V8 engines (I'm excluding I5, I6, I8, V10, exotics, & larger). With this in mind, what length should I be looking at getting which would cover these engines and why? (Please qualify and quantify your answer.)

Things to consider:

  • I don't want one which is too short, because then I'd not be able to handle the larger jobs.
  • I don't want to buy one too long, because then there would be added expense (ie: increased length causes cost to go up astronomically).
  • While a straight edge which is DIN 874 Grade 00 would be awesome, a Grade 1 or Grade 2 should work for my purposes.

NOTE: Please be mindful, I'm not asking which brand or which straight edge to purchase here. I'm looking for a way to understand what I should be looking at as far as length of the straight edge and why I should be going for it and not something longer or shorter.

Pᴀᴜʟsᴛᴇʀ2
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1 Answers1

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I would consider getting two. A straight edge flat steel square (machinist square) and a 36" straight edge should cover most standard applications.

The steel square will be great for smaller applications like small component mating surfaces. It has two shorter surfaces for easy handling. Even being able to check squareness could be helpful.

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The 36" should cover the larger areas like block and head surfaces. I found a place to get both for about $100 USD.

CharlieRB
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