Ebay micrometers, etc

[tminer]

Are any of those cheap mics on Ebay any good? I want them for engine checking and rebuild.

They seem to have all of the features that I want: ratchet stop, locks, carbide, .0001" readings and even claims of .0001" accuracy. But $50 or so for 6 of them seems too good to be true. I'll probably only use them a few times, and at that price I could get a $50 set of gage blocks (I assume those can be used to check calibration).

tyvm,
Tom

Edited to clarify.

 

[87GN_70GS]

You also might want to try Harbor Freight Tools.
http://www.harborfreight.com/

 

[TurboDave]

I bought set MS907 from these folks, and they're really quite a good set!

http://www.pitstool.com/Tools.php?c...er=&name=&partnum=&FormResults_Page=2#Results

 

[tta583]

Try these folks as well. I have ordered form them in the past. I will be honest in that I don't have a lot of background to make comparisons of their tools but I was very satisfied with what I purchased. I have bought a dial indicator, outside mic, bore mic, plus several other tools from them.

http://www.powerhouseproducts.com/

Brent

 

[tminer]

Originally posted by TurboDave
I bought set MS907 from these folks, and they're really quite a good set!

http://www.pitstool.com/Tools.php?c...er=&name=&partnum=&FormResults_Page=2#Results

Hmmmm...
Precision = Dayton, OH
Ebay KC international = Buckeye State

Precision = MS-907
Ebay KC international = 709-SM (MS-907 backwards)

Precision = Mitutoyo # 103-907 (is MS = Mitutoyo seconds?)
Ebay KC international = "Mitutoyo like"

Both = 69.95, vitually the same feature list (1 word different)

Thanks Dave.

Tom

 

[1of1547]

You get what you pay for. Stick with Starrett, Brown and Sharpe, or Mitutoyo(I own and use all three brands everyday). I have scene the "cheaper" precision tools at Carlise. They don't have a good feel. Normally mics over one inch come with standards to verifiy the are in tolerance. MSC or Travers have good prices on sets.

 

[TurboDave]

Originally posted by 1of1547
You get what you pay for. Stick with Starrett, Brown and Sharpe, or Mitutoyo(I own and use all three brands everyday). I have scene the "cheaper" precision tools at Carlise. They don't have a good feel. Normally mics over one inch come with standards to verifiy the are in tolerance. MSC or Travers have good prices on sets.

All well and good, IF I were a machinist by trade. I'm not, and can't afford to spend over $450 for a set of 6 mic's. Most of us aren't made of money

 

[1of1547]

Why do you need 3-4, 4-5,or 5-6 mics. All you really need are 0-3 mics. You can pick up a lower end set of any of the names I mentioned earlier for a decent price. Just watch for a sale on starter sets. They are going to more expensive than what you will spend for the others. But again you get what you pay for. If you are worried about money sell them on ebay when you are done. You wouldn't scrimp on the parts that you put into your motor would you? Why scrimp on the tools you are measuring all of your tolerances? Not trying to pick a fight here. I've seen many parts scraped because of many of these cheap tools.

 

[tminer]

I'm not made of money, a good thing since I've shed 125 lbs this year and couldn't take another hit after my 401Ks went down the crapper. But I do believe in investing in the proper equipment, within reason. No offense, but not liking the feel just isn't a persuasive argument.

I figured I'd need the 3-4" for pistons and the 4+" for any possible future non-3.8 liter projects. I only considered the 0-6" with the really cheap sets since they were only $20 or less over the 0-4".

Are the starter sets .0001" reading?

From what I saw, the cheaper Starrets, etc, do not have ratchet thimbles. My understanding is that machinist's and engine builders use the friction style but for a novice the ratchet is better since we haven't developed a proper, consistant "touch".

I might consider a 2-3" high end for the crank journals and use my .001 (.0005 accuracy) caliper for everything else.

tyvm,
Tom

 

[The Radius Kid]

I would check into tool suppliers like Proto,Snapon,etc. and see if they sell sets.
I bought a set of 0-6"[separate 1" increments W/ standards] from a Proto supplier a few years back.
Came in a wooden box all for $300 Canadian.
They look like they're off shore made[maybe China],with carbide anvils,.0001" accuracy and darned easy to read[big barrels W/ratchets].
Real nice.
I like them the best out of all my mic sets.
They beat the h#ll out my Starrets and my Mit's.

 

[tminer]

I'm not really looking for sources, they are pretty easy to find. I'm mostly interested in the downsides to these cheap price but high end specs units that are out there.

tyvm,
Tom

 

[1of1547]

No offense taken. What I meant was on the cheaper ones that I looked at did the thimble did not spin freely. The internal threads did not feal properly machined. Thus the had a very "choppy" feel. Being a machinist for 13 years I have seen alot of these cheaper sets. Most of the time they are not accurate after a period of time. Now that I am in Q.A. I see the problem alot more than I did before with some of our suppliers.
Yes the starter sets do go down to .0001. But you would have to check to make sure. My first set did. Radius Kid had a good point too. Check with the local tool dealers. They normally use NSK which are not bad either. Plus the are normally better priced. There are two different thimbles on mics. You have a rachet and a friction. A rachet sticks out of the end of the mic. A friction looks like a a normal mic. It has a extra sleeve around the thimble where you normally put your fingers. It will spin when you get the right tension just like a rachet will. These are the kind that I prefer.

 

[The Radius Kid]

I haven't really seen much in the way of downsides to this stuff,however I would take someone experienced to look at these for you if you are interested.

 

[QuickWrench]

Why do you need 3-4, 4-5,or 5-6 mics. All you really need are 0-3 mics.

You'll need the 3-4" piece for checking piston diameters, if you're measuring piston-to-wall clearance. However, you'll also need a dial-bore guage.

A friction looks like a a normal mic. It has a extra sleeve around the thimble where you normally put your fingers. It will spin when you get the right tension just like a rachet will. These are the kind that I prefer.

I agree, 100%...

 

[tminer]

I ordered a set of 0-6" for $69 and a 2-6" dial bore gage for about $55 from a place that has a no questions asked return policy: toolsolutions.zoovy.com .

I'll post back when I get them.

Tom

 

[The Radius Kid]

Good point.
NEVER trust a vernier for anything closer than a couple of thousandths.
To much built in slop.

 

[The Radius Kid]

Originally posted by stevemon
obviously why I've always called them "very-nears" instead of verniers.

Good one.Who says machinists don't have a sense of humor?
I bought a set of Mits 0-12" depth mics and found them to be somewhat loosey goosey on the spindle thread adjustment.
I adjusted it to satisfactory operation,but I'd hate to think that Mits' quality is going down the toilet these days.

 

[tminer]

They are not digital.

There is a difference between gradient resolution and accuracy:

If a measurement is exactly on the .250" grad line and accuracy is .001, then the real measurement could be .249 - .251". At .0005 accuracy it could be .2495 - .2505". All the grads do is set the point at which the measurement must be eyeballed. That can lead to another tolerance, but that is due to the eyeball, not the instrument.

Tom

 

[tminer]

Got the mics and dial bore today. Cheap cases and absolutely no instructions. But they seemed to be OK. They felt solid and smooth. Didn't seem to be much slop in the mechanism. I don't have any real experience with mics, but I'm approaching geezerhood, and been around a bit of precision stuff off and on over the years.

Am I correct that the .0001 reading is the one closest to ANY .001 grad?

Tom

 

[geno]

At Boeing they wont even cert a cheap tool and make you take it home. (They call them hobby tools)You pay for what you get and if you want repeteable readings time after time you need good stuff. The most important thing about using mics is to have a good feel. Ive seen lots of off brands read .0001 but thats just a number to make you feel good about it LOL....Alway use a known standard before using any tool if you going to use the numbers for a tight tolorance. I wouldnt even think about a cheap bore gage and mike to check rod and main clearances.. Ive seen lots of good money spent on cheap tools because of the problems they have caused. But a cheap set of mikes will work for the hobby guy but not in a good machine shop that uses them everyday. There is no room for erorr if you cut a crank small..
I would buy a used set of high end mics before id buy the hobby stuff myself..

Brown and Sharp also make nice stuff.