FiendFX
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Can someone recommend me one? Im thinking of getting the one from harbor freight since its only like $10. Are they accurate? This is for brake job.
Digital Calipers
- Thread starter FiendFX
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They used to be decent but have gone downhill. Just get Mitutoyo Digimatics and don't look back.
helterskelter
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Mitutoyo's are pricey. Mind you I own multiple pairs of mits and my favorite pair is a set of digimatics with carbide tips.
If you just want to get in the ball-park, then cheap calipers are fine. If all you ever use them for is the thickness of a brake caliper then there's no need to dump 150$ into mitutoyos.
I use my calipers (and micrometers) to measure parts where accuracy is important. Thus I own nice ones.
If you just want to get in the ball-park, then cheap calipers are fine. If all you ever use them for is the thickness of a brake caliper then there's no need to dump 150$ into mitutoyos.
I use my calipers (and micrometers) to measure parts where accuracy is important. Thus I own nice ones.
helterskelter
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I'll send you a pair of dial mitutoyo's that failed calibration for one reason or another (generally .001'' wear on the ID tips) for the price of postage.
Dang! Jump on that one, OP!
helterskelter
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Bull - I'll send you a set too if you need them and will use them.
4xdog
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This is true. I have a couple of the HF plastic ones to make no-scratch measurements and I have to keep the batteries out of them or else they'll be dead in a month or less. Their low price shows up in stuff like this.
Ironically, I also have been looking at cheap digital calipers, specifically the Titan brand. I picked up an old micrometer once, but they were 2-3" range and I never found anything that large that I actually had to measure. I do encounter smaller things that I'd like to measure, though.
And actually, as I write this, I question whether I know the difference between the job a micrometer does and that a dial caliper does...
helterskelter
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Bull - A nice set of calipers in well trained hands is good for maybe +/- .001'' accuracy (maybe less at the extremes). A nice micrometer will measure in the .0001'' range. You use a micrometer for precision measurements.
A caliper is much more versatile because of the shape, the ID measurements and the depth measurements. For 99% of the stuff you'll do, a caliper is probably the correct instrument. If you *need* a micrometer, then you might want to take it to someone with some experience using one. I use a caliper for the majority of the measurements I take, but there are times I need to know down to the .0001'' and a micrometer is one tool that will do it.
A caliper is much more versatile because of the shape, the ID measurements and the depth measurements. For 99% of the stuff you'll do, a caliper is probably the correct instrument. If you *need* a micrometer, then you might want to take it to someone with some experience using one. I use a caliper for the majority of the measurements I take, but there are times I need to know down to the .0001'' and a micrometer is one tool that will do it.
And actually, as I write this, I question whether I know the difference between the job a micrometer does and that a dial caliper does...
They both do the same thing, but micrometers measure in a shorter range like 0-1'', 1-2'', 2-3'' etc.
It must have been a caliper that I had, then. Shaped like a question mark, basically?
I'm the equivalent of a slightly evolved caveman when I work on stuff, so I will certainly not be needing anything in the .0001 range! I've wanted to measure shafts, rotors, bolts etc. plenty of times, though.
Stooge
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We mostly use mitutoyo calipers in our lab and what we send out to our field guys, seem to last awhile and stay within tolerance. For most of our field calibration kits, we use fowler calipers. They have quite a few different levels from $30ish to a few hundred. Seem to be a pretty good quality but not quite mitutoyo level, more than enough to check rotors without getting too spendy
helterskelter
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A question mark is a micrometer. They're usually 1-2'', 2-3'', 3-4'', all the way up to very large ones. A caliper is usually 0-6'' 0-8'' 0-12'' all the way up to the large ones. For your needs, a set of calipers is plenty. A 6'' scale is probably good enough for most things.
helterskelter
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Send me a PM and I'll send you a pair of carbide tipped mitutoyos with a dinked ID jaw (small dink, easily worked around). They could use a new bezel, the plastic is scratched on this one. Same goes with OP.
bczygan
Well-known member
helterskelter is right.
I work in a one and a half man machine shop (I'm the 1/2), and when I am cutting metal on the horizontal band-saw I measure with an accurate scale, and after cutting the first one (Set against a stop), I check it with a caliper. Usually I am cutting 30-50 over to allow for milling, so the caliper lets me know if I'm in the range so I can tap on the stop to adjust it.
When I am working on the Bridgeport and milling the part to exact size, the micrometer will let me know if I'm within a couple thou, which is usually more than good enough.
I work in a one and a half man machine shop (I'm the 1/2), and when I am cutting metal on the horizontal band-saw I measure with an accurate scale, and after cutting the first one (Set against a stop), I check it with a caliper. Usually I am cutting 30-50 over to allow for milling, so the caliper lets me know if I'm in the range so I can tap on the stop to adjust it.
When I am working on the Bridgeport and milling the part to exact size, the micrometer will let me know if I'm within a couple thou, which is usually more than good enough.
OccupantRJ
Well-known member
A decent dial or digital caliper will measure in 4 modes. Inside, outside, depth, and step. Seems a lot of people are not familiar with the step measuring technique. Here's a link to measuring with calipers.
http://littlemachineshop.com/Instructions/UsingCalipers.pdf
http://littlemachineshop.com/Instructions/UsingCalipers.pdf
Charles (in GA)
Well-known member
You generally cannot use a caliper to measure a brake rotor, except for a new one. After they have been run, the rotor has a raised edge on it where the pads don't contact, and this edge prevents the caliper from seating down on the polished/worn portion of the rotor.
A micrometer has tips that allow it to fully contact the worn portion of the rotor, and they do make calipers with special tips that also are intended just for brake rotor measuring.
Charles
A micrometer has tips that allow it to fully contact the worn portion of the rotor, and they do make calipers with special tips that also are intended just for brake rotor measuring.
Charles
bczygan
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helterskelter
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Another option if all you have is a regular set of calipers is to use some gage blocks as stand-offs. There's plenty of ways to do it and get 'close enough'. I agree though, I'd rather use a micrometer to measure a caliper because of the shape of it (never actually measured one before, just toss them when they look spent).
928'er
Well-known member
Charles is right.
However, I think a cheap set of HF calipers could be easily modified to clear the raised edge. A few minutes with a die grinder (or Dremel tool) should do it. At 10 bucks a pop not much to lose and it should be more than adequate to measure the thickness of a brake rotor with reasonable accuracy. It's a brake rotor after all, not exactly rocket science.
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98TJ
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I have a pair of Starrett digital calipers that have done me well over the years.
I think only for initial production/manufacturing like setting CNC machines, accuration and perfectly calibrated meters (calipers, gauge, micro, etc) absolutely needed. But down to end users or repairman those pricey accuration is not that so important, usually there is no need to have dead on measurement but only to know allowable tolerances. Of course anyone at end user level or repairmans will love to have that high end meter or calipers with carbide tipped.
As just a suggestion for a digital vernier type caliper, AZ house brand seems to be decent.
I can't say for accuracy to any level but the AutoTEC branded one has served me well a few years now. I get about 2 years battery life with infrequent use.
I have only used them in general shop uses checking tolerances and such, I'm not a machinist at all.
I can't say for accuracy to any level but the AutoTEC branded one has served me well a few years now. I get about 2 years battery life with infrequent use.
I have only used them in general shop uses checking tolerances and such, I'm not a machinist at all.
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Skandsen
Active member
I bought a cheap digi caliper from McMaster and it's great! How accurate I dont really know.
As for measuring rotors, visual/feel checks is all I need to do (street or race). Then it's either still good or replace. But I dont have any fancy floating rotors or anything, just regular $100 per axle vented Brembos (the US made Brembos last longer on the racecar).
How accurate I dont really know.As for measuring rotors, visual/feel checks is all I need to do (street or race). Then it's either still good or replace. But I dont have any fancy floating rotors or anything, just regular $100 per axle vented Brembos (the US made Brembos last longer on the racecar).
Ign
Well-known member
This. The cheap ones **** on the battery even when the display is off. Otherwise ok, but this is one reason I keep rack 'n pinion calipers in the truck - no battery to ever die. But in the shop dust and chips kills the rack so digital is the way to go.
Ign
Well-known member
You can also pick up a cheap set of Jo Blocks and use them as "stepovers" to get over the edge. Just subtract the thickness of your blocks and bam, rotor thickness. Truthfully you could do this with any stock of known thickness, just measure it with the same calipers before using it.
SMKS
Well-known member
I have the HF digital calipers and they're worked fine for me for several years. I've definitely got my money's worth.
If I was measuring critical things perhaps I would buy a better brand. But the most critical thing I use it for is measuring bike seat posts, so it has served me well.
If I was measuring critical things perhaps I would buy a better brand. But the most critical thing I use it for is measuring bike seat posts, so it has served me well.
Steinmetz
Well-known member
You need a brake disc micrometer. Not digital (or any other variety) calipers.
You guys approve this?
http://www.amazon.com/dp/B006Y1OWKS/?tag=atomicindus08-20
Autozone also has one for $50 from OEM.
http://www.amazon.com/dp/B006Y1OWKS/?tag=atomicindus08-20
Autozone also has one for $50 from OEM.
basspro
Well-known member
We used to purchase Mitutoyo Digimatics for the production workers at our facility, since the majority wouldnt take care of them, we have gone to SPI digitals, around $30, and they are fine at that price. I myself have Fowler dial in metric and Starrett dial in SAE, both are very nice as I prefer dial over digital myself, just what I learned with.
my Grandfather's Starrett micrometers
the inch/mm Tesa vernier caliper from '71 on my desk
the Tesa dial calipers, inch and mm ones in my tool box
and my TesaMaster micrometers with ball bearing spindles for measuring cranks and pistons etc to 0.001mm, yes, 39 millionths
no batteries
or Mickyoyos at my house
the inch/mm Tesa vernier caliper from '71 on my desk
the Tesa dial calipers, inch and mm ones in my tool box
and my TesaMaster micrometers with ball bearing spindles for measuring cranks and pistons etc to 0.001mm, yes, 39 millionths
no batteries
or Mickyoyos at my house
RCStocker
Well-known member
Chinese machinist tools are all **** and I mean ****. They work but they are such poor metal and so full of slop that they don't last and I would not trust them at all. I was a tool and die maker in my former life. Starrett or Mitioyo are the only 2 brands I would buy. You can find them for $30 or $40 used on Flee bay all the time. Pox on JF Shame on you for even thinking about one. They would laugh you out of any machine shop or good garage. I know you would not bring them into one of my shops and use them. If you did you would get fired.
If that is all your doing then they will be fine. Be careful measuring a hot rotor though
Sadly, the place I use to work would purchase those by the case. Send them through the in house calibration lab and pick out the best ones. Amazingly a very high percentage of them were dead on. They were not as impervious to coolant and chips like the higher end ones though. My personal favorite digital calipers are the Mitutoyo Absolutes, but there is a slight price difference between those and the HF specials.