Precision Straight Edge

[Grogan14]

I'm wanting to buy a straight edge, for checking cylinder heads and such. One of 24" would meet my current needs, but I probably will own a inline-6 or something other that might require something longer at some point down the road. Should I just get a longer one now, or are there times when the longer one would be disadvantageous?

Also, is .001 accuracy on it good enough for home use? Advance Auto has Central Tools brand ones on sale right now, plus there's the coupon codes...

Thanks

 

[tube_guy]

I've never had trouble with a longer straight edge and I opted to buy the longest that I could afford. 0.001" across the entire length of a 36" straight edge is quite good. I've never seen one that's really bad myself, but I've heard quite a few stories about people having trouble with straight edges that are not very straight, even though their specs say they are. Particularly the "straight" edges coming from China. I've had great luck with the Veritas 36" steel straight edge that's available from Lee Valley at:

http://www.leevalley.com/US/wood/page.aspx?p=56676&cat=1,240,45313,56676

 

[ihredo4]

I bought a piece of precision ground stock instead of the "automotive straight edge" that they sell for $100+. Check with Grainger, McMaster Carr or something like that. Price was 1/4 of some of the ones I saw.

 

[Packard V8]

Yes, I've got a straight edge, but almost never use it. We automatically resurface every head. With the time it would take to really check it carefully with a straight edge, it can be on the mill and half done. Plus, it just looks a lot better.

jack vines

 

[williaty]

0.001" flatness is not good enough for many engines, sadly.

 

[Travis E.]

If that's all the flatness you need you could also purchase some precision ground flat stock for much less. It obviosly would not have the marking a ruler would.

 

[A_Pmech]

FYI: Precision ground flat stock is not specified by the manufacturer to be straight to any degree of accuracy. The only things the manufacturer will assure is that the dimensions of the flat stock meet a given tolerance on size, squareness of perpendicular edges, parallelism of opposing faces and surface finish. It could look like a bananna and pass QC and, in fact, I have received bananna shaped flat stock from reputable US manufacturers.

 

[Travis E.]

Maybe I am lucky and have not seen a piece like that. I check them on our Comparator or OGP when needed.