Dear all,

I will try to use dial caliper for replacement digital caliper.
Does anyone know which is better? (Investment Cost, Preventive Cost, and Life Time)..

Thank's
JHonie

Does anyone know which is better? I suppose that depends on how and for what you intend to use it...

Personally, I prefer the digitals but that is mainly due to poor eyesight. Their main disadvantage used to be that they gobbled up batteries very fast, but I don't think that is an issue these days.

Durability? Who knows... There are fewer moving parts in the digitals, of course.

/Claes

Digital caliper is more visible comparing the dial caliper, and the main advantage of it, is that discrimination of digital calipes is higher. It depends on the tolerances of the dimension whether digital or dial caliper is preferrable. If the discrimination of the gage is sufficient for the tolerance thant it would be an unnecesarry investment to use the digital. Generally cost of the digitals are higher.

Dear all,

I will try to use dial caliper for replacement digital caliper.
Does anyone know which is better? (Investment Cost, Preventive Cost, and Life Time)..

Thank's
JHonie


I have come to prefer digitals over dials for several reasons.
1) Easier to read: Less chance of a reading error
2) Durability: There are virtually no moving parts. No gears for dust and dirt to fill and damage
3) Flexability: Most switch from inch to mm easily plus you can set zero at any point which can be very convenient for measuring c'line distance between holes.

I don't feel that the discrimination of dial vs digital calipers is sufficient in most uses to to matter.
Also, most new calipers use 1 small (SR44) battery that is inexpensive and last quite a while.
Cost can be a factor, however there is a company we have bought quite few calipers from called "Harbor Freight". They have 6" digitals for under $20 US. They are on the internet.

Hope this helps

James

My one complaint about most digital tools is the 'set zero wherever you like' feature. While very helpful if you know what you are doing, I've worked in far too many shops when a mis-zero'ed digital caliper or micrometer ran a lot of scrap parts. Micrometers(larger the 1 inch/25mm) are especially epidemic for this problem.

My previous employer only used traditional tools for just that reason. We had to let a digital from engineering out in the floor, within a week that problem came up.

If you go digital, be sure to errorproof that issue as best you can.

Dear all,

I will try to use dial caliper for replacement digital caliper.
Does anyone know which is better? (Investment Cost, Preventive Cost, and Life Time)..

Thank's
JHonie

One of the machinists at our facility has an old digital that he's been using for over 15 years now so longevity probably isn't an issue, but cost would be a bit of a difference. Some of the name-brand digital units can be somewhat more costly, but an advantage to digital is its ability to give you direct SPC information. I don't consider batteries a maintenance cost. We supply batteries and replace worn personal measuring instruments at company expense since accuracy has a direct impact on product quality. I do find more accuracy/repair problems with chips/fines getting into the dial caliper rack and dial system than I see with the digital caliper's smooth beam.

I personally like Dial Calipers over Digital, I don't know for what reason.

One of the drawbacks of digitals is they read out to 4 decimal places. Calipers have too much inherent operator error to be this accurate. On the other hand, there is no error in reading a digital. Digitals are usually more expensive, although sounds like James found some reasonably priced units.

I haven't used any measuring tools from Harbor Freight, so have no experience with them. On the other hand, from a tool viewpoint HF is not known for the robustness/quality of the tools they sell - primarily inexpensive tools manufactured in the Far East. I'd hesitate to use a fine measuring instrument purchased from them until I had done an MSA with the instrument in question. One purchase Starret, Mitotuyo, Fowler, etc. measuring instruments for a reason.

From a digital versus dial stand point, I'd prefer digital. I beleive they provid better operator discrimination of the readings.

Another aspect which may need to be considered is the effect of apparently higher "accuracy" of digital instrumentation on the overall manufacturing process capability.

I have seen considerable improvements in manufacturing process capability when we switched from calipers to digital micrometers without any actual change in the process by simplyly improving GR&R from 10% to 3%

So if your current process was borderline using digital you run the risk of dropping under capability limit if the accuracy of instrument is degraded.

Another aspect which may need to be considered is the effect of apparently higher "accuracy" of digital instrumentation on the overall manufacturing process capability.

I have seen considerable improvements in manufacturing process capability when we switched from calipers to digital micrometers without any actual change in the process by simplyly improving GR&R from 10% to 3%

So if your current process was borderline using digital you run the risk of dropping under capability limit if the accuracy of instrument is degraded.

I understand what you're saying (that's why MSA is important) but just to clarify, the process capability didn't change; your ability to accurately evaluate it did.

Most digital instruments can be hooked up directly with computers using RS232 for on-line data capture...just something to consider, in case you need this capability.

I haven't used any measuring tools from Harbor Freight, so have no experience with them. On the other hand, from a tool viewpoint HF is not known for the robustness/quality of the tools they sell - primarily inexpensive tools manufactured in the Far East. I'd hesitate to use a fine measuring instrument purchased from them until I had done an MSA with the instrument in question. One purchase Starret, Mitotuyo, Fowler, etc. measuring instruments for a reason.

From a digital versus dial stand point, I'd prefer digital. I beleive they provid better operator discrimination of the readings.

You are right. Harbor freight is not known for the finest products around, though I must admit to using a number of their tools and being pleased with them. We have two outlets in the Cincinnati Area so I don't have buy sight unseen.
As for the calipers, they are of good quality, especially for the price. I was quite pleased. Quite a few folks on the shop floor have used them and I do the calibrations/verifications on them. As with most things, the durability of them is largely dependent on the owner. Those who care for their tools have better "luck". The one thing I have noticed with both the digitals from harbor freight and similar ones from Mitutoyo is a tendency for the Battery cover to come loose over time.

anyway that has been our experience.

James

The basic considerations include, but may not be limited to:

Resolution. Digitals usually have better resolution. That does not necessarily mean accuracy.

Ease of reading. Digitals are easier to read generally, but someone well used to a dial is often equally good.

Actual use. If the dial caliper is fine for the intended use, then will a digital increase the ability, or will the increased resolution not really help?

Uncertainty. Your uncertainty for calibration is not likely to change a lot, but there will be some change. If the digital goes to four places, and the uncertainty is 670 microinches let's say, will that affect your measurement the same way as a dial that goes to three places?

Put another way, a simple answer depends on what you need to do with it.

Hope this helps.

Hershal

I understand what you're saying (that's why MSA is important) but just to clarify, the process capability didn't change; your ability to accurately evaluate it did.

Yes Jim you are right and the point I was trying to make poorly :o was the "apparent" process capability in ongoing SPC might appear to degrade even though it really has not.

I may be English but Yorkshire Tyke is my first language:rolleyes:

Dear folks,

you're absolutely right, stating that it is much easier to read a digital caliper - as, like me, some might claim for a vast improvement in glasses technology... :cool: - however from my experience there are at least two disadvantages inhered in digital technology:

- men trend to trust in digitals more than to themselfes, so my experience is, that often due to missing zero point settings, etc. digital measurements can have additional failure modes

- sometimes, due to internal failures (algorithms in the chip, low battery, number calculations and stuff like that) in certain conditions you can get basic measurement failures

So, in any case I recommend to perform a measurement system evaluation it its strict meaning AND in the intended measuring area (if feasible even at the desired measure and tolerance area)!

Then there is another point of view to be considered: Most of the calipers show two digits after the decimal point, however how is this feasible? Sure, the electronic parts and the scale allow an even much higher resolution, but keep in mind: Its a caliper! So, dust, wrong alignment, measuring force, etc. have a much higher influence to the measurement than the electronic ingredients.

In conclusion here I would state: I would not want to trust on a pocket calculator - nor on a two digit digital measurement from a caliper :notme:

Best regards
Markus

Hi. New here, but what about buying / borrowing one of each and conducting two equal gage R&R, compare the result, ask your operators what they think, and select which one works best for your system.

As for setting the zero improperly, you will need to make this part of your procedure, and maybe audit and train people to follow it. If the operators take pride in there work and are aware of that weakness they will keep an eye out for it and prevent it.

edit: woops did read the last post date.

Hi. New here, but what about buying / borrowing one of each and conducting two equal gage R&R, compare the result, ask your operators what they think, and select which one works best for your system.

As for setting the zero improperly, you will need to make this part of your procedure, and maybe audit and train people to follow it. If the operators take pride in there work and are aware of that weakness they will keep an eye out for it and prevent it.

edit: woops did read the last post date.

First of all Welcome and thanks for the input. I wouldn't worry too much about the last post date, Old threads are resurected from time to time and that is a good thing.

You are right about the training issues you raise. Any tool regardless of it's readout, cost, durability, precision etc. is only as good as the person using it. If the operator does not know how to properly use an instrument disaster will likely follow. - - - Been there - Seen that:frust:

Where I worked I handled the calibrations and verifications as well as some training. The scale and scope of misreading and mishandling measuring instruments can boggle the mind. It reenforces the old adage about foolproofing: The problem with foolproofing is that they keep making new and improved fools.:bonk:

James