Micrometer to check engine specs

[Lagersolut 723]

I'm looking to add a Mic to the toolbox , Amazon has them form anywhere in the 20-80 dollar range, are these accurate enough, trust worthy enough etc .

Broad range of prices and I imagine quality as some tool houses are getting 150-300 .

Recommendations or bewares  ?

I only go over an engine once in a while but it's something I'd like to purchase .

[MikesRJ 555]

If it's cheap, it's probably not a good one. The cost of machinist tools is truly states as, "You get what you pay for." Only good recommendation I can make is; Buy Starrett and you can't go wrong.

Edited August 19, 2015 by MikesRJ

[JAinVA 4,629]

I agree with the adage that you get what you pay for.With that said ,as a journeyman machinist with over thirty years in the trade,I don't own any Starrett tools.It depends on what you need and what you want to spend.If you buy an inexpensive set of micrometers that come with standards you can check a  mike at both ends of it's range.If you are a careful casual user I doubt that paying for the Starrett name is necessary.You might want to look at what companies like Travers Tool have to offer.They offer you a choice
of name brand USA made tools and inexpensive imports.Unless you are building HiPo racing engines you probably don't need a micrometer that costs $150.00.I try to buy
American made tools when I can  but my first mike was Mitutoyo 1" which lasted me over twenty years making parts for NASA.JMHO,Luck,JAinVA

[Aldon 4,828]

Seconded - Mitutoyo are very good.

 

[pacer 3,176]

I have both, Brown  Sharpe, Starrett, etc and I also have Chinese. I bought the Chinese thinking to use one on just run of the mill projects and keep the good stuff for the good projects. I quickly discovered the the import products were very nice and in comparison measurements of the two types - they measure the same. I think for the occasional use a mic would see in the typical home shop the Chinese tools are quite acceptable. Most of the tool suppliers have a 3 mic set for under $50 and would cover most anything you would typically use one for.

[Lagersolut 723]

Would a caliper style like this be OK  for checking the tolerances ?

[JAinVA 4,629]

In my opinion no.You really need standards to check the accuracy of the caliper.Most micrometer sets have standards(precision length metal rods) to ensure that the micrometer is giving you an accurate reading.Most calipers don't come with standards to check accuracy.I'm sure that the tool shown is a well crafted accurate caliper
but if I could not check against a standard or a Johanson block I would not use it to measure engine parts.Again unless you are building HiPo engines you might get by with this, just don't  use the it to measure the bore unless you have a telescope gage.The internal measurement will be off if there is a ridge in the block and you need to measure
the block at several points through out the stroke length.Hope this makes sense.Luck,JAinVA

[Lagersolut 723]

In my opinion no.You really need standards to check the accuracy of the caliper.Most micrometer sets have standards(precision length metal rods) to ensure that the micrometer is giving you an accurate reading.Most calipers don't come with standards to check accuracy.I'm sure that the tool shown is a well crafted accurate caliper
but if I could not check against a standard or a Johanson block I would not use it to measure engine parts.Again unless you are building HiPo engines you might get by with this, just don't  use the it to measure the bore unless you have a telescope gage.The internal measurement will be off if there is a ridge in the block and you need to measure
the block at several points through out the stroke length.Hope this makes sense.Luck,JAinVA

My purpose for it would be stock small engines ....example :  to check the crank for wear/round  to determine if it does or doesn't need machine shop work for .010 under rod etc.

But yes, everything you're saying makes sense .  I'm trying to educate myself a little and get as far into getting readings to determine if a trip/call  to the machine shop is necessary or not. The numbers/mathematics portion are no problem, but I want to know I'm getting the correct ones . ( numbers/measurements  ).  The amount of engine work I get into is minimal , so going "all in "  hundreds of dollars in tools to do an engine or two ( Briggs- Kohler )  really wouldn't be worth it to me.

Edited August 21, 2015 by Lagersolut

[pacer 3,176]

Would a caliper style like this be OK  for checking the tolerances ?
 

In a word --- no, tolerances are best done with more precision devices --- but... a caliper is a truly handy tool to have in the shop. I am constantly using one of my 3 that I keep scattered around the shop, from checking the diameter/length of a bolt to measure the thickness of a piece of scrap steel, to etc, etc. Here again I have both quality and cheapo. I have Brown & Sharpe for quality and HF for general duty.

[JAinVA 4,629]

The calipers shown will let you know if you have a crank that is not round.I would not be concerned with that use of it.The bore could be checked to see if it is standard
or bored as well.The problem comes when you are trying to come up with true sizes.I have the tools to do my measurements because I work on all kinds of projects that justify the expense.If you are just going to do an occasional rebuild I would suggest you look at a 0 to 6 inch mike set and some telescope gages.There are many sources
such as Travers Tools and others to find these items at a price that you can afford.I hope this helps.Luck,JAinVA. Jim

[clem 28]

Precision measuring tools are very handy to have around for all of the reasons mentioned here, no matter if they're low buck or high dollar. If your need for them is going to be rare, you might consider taking your engine parts to a machine shop of your choice and let them measure things for you. This may help save from investing in tools that may not really get used much. I do agree that well kept calipers, mics, and a few other items are quite handy though.

[Coadster32 793]

Calipers are regarded as "for reference only", in the world of machining. China mics are just that. The good news for you is that machinist tools don't hold their value well. So...for the price of some new china junk, you can get some really nice used quality micrometers. Mitutoyo, Brown and Sharpe, or Starret have been the top brands for decades strong. As stated, you'll want some telescoping gages for checking the cylinder bore sizes accurately. Calipers are handy to have, but not for precise work..(have I said that already?)

[Lagersolut 723]

Thanks for the info guys - I think for the cost I'll just continue to do what I've been doing - if I think/know  there's a problem getting things tore down and just take the stuff to the machine shop.

The more I think about it the more I trust a guy that does it for a living and knows his tools are giving him the right numbers .