# Working to Tenths with Economy Tooling



## erikmannie (Jan 17, 2020)

So after spending about $2500 on Shars tools, I sat down to measure the gage blocks in my economy gage block set with my 0-1” digital electronic micrometer. This went pretty badly.

I am new to machining, so part of this could be attributed to operator error. Put simply, the micrometer and gage blocks are okay to a .001” but not to a tenth. An example of this is that the .0107” block surely measures thicker than the .0108” block.

So many people told me to buy Starrett, Mitutoyo, etc., but I was enticed by the low prices of the import tools. I am afraid that I did not spend the $2500 as wisely as I could have.

Has anybody had success working to a tenth with import metrology equipment? I can definitely work to a thou and maybe even to 3 tenths, but as far as I can see the Shars tools aren’t getting me to a tenth, if the gage blocks and 0-1” digital electronic micrometer are any indication.

I am now at the point were I will only be buying the quality brands moving forward. I plan on relegating all of the Shars equipment to the shop, and saving up for an inspection room later equipped with quality tools.


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## Technical Ted (Jan 17, 2020)

I can't really answer your questions, but want to remind you of a few points...

Measuring that closely requires an atmosphere with controlled conditions (temperature, humidity, etc.). Further, touching gage blocks and/or micrometers with your hands will through your measurements off because of temperature. Micrometers that measure tenths are best if they have friction thimbles that are used, because a machinist' "feel" can be way off when measuring that closely.

Edit: And everything needs to be PERFECTLY clean!

In my experience, measuring to within a 0.0001" repeatedly, with a basic hand held micrometer, is extremely difficult and results will vary.

So, regardless of the brand of tools you use, if not used correctly you will get inaccurate readings.

Good luck,
Ted


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## C-Bag (Jan 17, 2020)

Technical Ted said:


> I can't really answer your questions, but want to remind you of a few points...
> 
> Measuring that closely requires an atmosphere with controlled conditions (temperature, humidity, etc.). Further, touching gage blocks and/or micrometers with your hands will through your measurements off because of temperature. Micrometers that measure tenths are best if they have friction thimbles that are used, because a machinist' "feel" can be way off when measuring that closely.
> 
> ...


+1. Ted nailed it. The allure of perfection through metrology is very strong for some of us. But it takes years of experience to attain it consistently and more than that to know when it's even necessary. It's easy to go into a perfectionist loop especially when new because you don't know all the variables. Working to .0001 is getting into some pretty fussy territory and besides a temperature controlled clean room that you keep your metrology equipment in do you have a set of ground tool room stones? A set of precision ground tool room stones has become my first step down the rabbit hole of chasing tenths.


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## Bob Korves (Jan 17, 2020)

Gage blocks should be accurate to within .00005" or better, depending on the grade.  I have heard of gage blocks being mislabeled in Chinese import sets, and I also check mine each time I use them as a reality check to make sure that mistakes were not made in labeling them.  We cannot test them to their exact accuracy in our shops, as explained in the posts above.  Part of what makes the Chinese stuff so cheap, even with a boat ride across the ocean, is bypassing strict quality control and quality assurance.  It leaves us to be the final inspection techs, like it or not...


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## projectnut (Jan 17, 2020)

I would agree to the above statements.  The shop I worked in was temperature and humidity controlled.  Even then the inspection room was sealed off with it's own heating, air conditioning, and humidity control.  Critical parts were allowed to acclimate in the inspection room for 24 hours before final inspection and certification.  To insure accuracy the inspection tools were calibrated and certified on an annual basis.  In this incident the OP is "assuming" the micrometer is properly calibrated and the gauge block is in error.  It could very well be just the opposite.

In addition to the tolerance problems introduced by humidity, temperature, and handling, I doubt that most hobbyist grade machines could consistently produce parts within .0001" tolerances.  Add to that the fact that very rarely do parts need to be held to those tolerances.  In my opinion it's a waste of time and effort to machine a part to tenth tolerances, when plus or minus .001" is well within what's needed for the application.

I've said it before, and I'll say it again.  In the commercial world time is money.  There are a minimal amount of times when such tight specifications are justified.  The rule of thumb at our shop was "For every space you move the tolerance decimal point to the left, you move the cost decimal point to the right."


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## NCjeeper (Jan 17, 2020)

I have had good results with Shars stuff. How accurate are the gauge blocks you are using?


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## pontiac428 (Jan 17, 2020)

projectnut said:


> I doubt that most hobbyist grade machines could consistently produce parts within .0001" tolerances.  Add to that the fact that very rarely do parts need to be held to those tolerances.  In my opinion it's a waste of time and effort to machine a part to tenth tolerances, when plus or minus .001" is well within what's needed for the application.



I can't touch off a face on my mill or square my vise to .0001 inch, and I can't center stock in my lathe to .0001 either.  Most of the time I can't even make a part to .001 all around.  Most dimensions on a part can be fine at .005, with only the important fitted features on the part at higher tolerances as necessary.  Most of the time, unless I'm using a dial indicator or have some critical fit, I leave the tenths alone...


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## Janderso (Jan 17, 2020)

All my machines are 50+ years old. I'm happy dabbling in the .001" world..
I do have some Shars blocks, they are very accurate.


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## mikey (Jan 17, 2020)

I am guessing here but when most of us check our tools against a known standard it is to confirm that the tool is accurate enough to trust it. This has nothing at all to do with whether or not some new hobby guy can *work* to tenths or not; its about confidence in the tool. If I check a set of digital calipers with a gauge block set that is accurate to 50 millionths of an inch, that gauge block set should tell me if the calipers can read within 0.001" accurately. If it can, then it can be trusted to function within its known or stated range.

While I agree that the ideal is a temp and humidity controlled environment and the standards and the tool is left to soak for 24 hours, we are not trying to *certify* a tool in our shops; we just want to know that the tool reads accurately within the stated limits of the tool. A caliper should read within a thou, a mic should read within a tenth and so on. If it does, we trust it and if it doesn't then we don't. I don't think we need lab conditions to get that level of trust.

My gauge block set came from a German metrology lab. It is used but is supposedly accurate to 50 mil. I use it to check my tools in my air-conditioned home but I don't worry too much about the conditions beyond that. I work cleanly and those blocks are accurate enough to give me confidence in my tools, all of which are high end tools except one - a Chinese caliper I recently bought to abuse in the shop - and even that one falls within specs.

If a hobby guy's mic reads 0.1234" then he can plan his cuts to come in on size from there IF the reading is true. He may want a diameter of 0.120" but he can't get that unless he knows where he is starting. 

It's as simple as that.


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## benmychree (Jan 17, 2020)

A gage block set of 50 millionths accuracy (1/2 of a tenth of a thousandth) is quite at the low end of the totem pole so far as accuracy is concerned, truly accurate sets such as an A+ set is something like +3, -5 millionths accuracy tolerence.  In my opinion, gage blocks are nearly useless in hobby shops, except possibly for bragging rights among other like minded hobbyists.  Their only real use is to set up sine bars or fixtures.  They are not very good for setting mikes because of the difficulty of achieving a parallel fit, plus the stacking error inherent in cheap block sets; half a tenth here, half a tenth there; it adds up or subtracts down the more blocks used in a stack.


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## projectnut (Jan 17, 2020)

I go back to the last 2 sentences in my previous post.   "In this incident the OP is "assuming" the micrometer is properly calibrated and the gauge block is in error.  It could very well be just the opposite."  Without a controlled atmosphere how can the OP be certain which component is causing the difference from the measurement stated on the block.  Simply handling the block long enough to raise the temperature a few degrees can cause the dimensions to change.  Given a micron is .000039" and tool steel expands at a rate of 12.8 microns per degree, it would take less than a 5* change (from the standard of 68*) in temperature for a block to expand .0001".  Any lint or even a finger print on either on the micrometer or the gauge block could account for the difference in measurement.

I agree with John York's assessment of the use of gauge blocks in a hobby shop.  Mine were originally purchased to setup a sine bar.  I must admit however I have been known to use them to check the accuracy of a micrometer.  I have a number of micrometers in the shop.  The newest were purchased in the 1980's.  The oldest date back to WWII.  Even the oldest ones are good to within a tenth.  That's close enough for anything I do.


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## middle.road (Jan 17, 2020)

File to size, Hammer to fit.


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## erikmannie (Jan 17, 2020)

I bought the gage block set at the same time as a 6” sine bar. I only have 30/60/90 and 45/45/90 angle blocks, and I don’t plan to buy an angle block set, thus the sine bar. I am new to machining so I am probably getting a lot of things wrong.

The truth is that I will probably try to achieve a few tenths tolerance and be happy with a .001” tolerance. When I took machining classes, a thou was the goal (except for cutting threads).

Using the economy micrometer to measure the economy gage blocks led me to question whether or not I have handicapped myself by buying cheaper import tools. Generally speaking, the Shars equipment seems to hover very close to the “is it good enough?” standard. Yesterday I organized all of the Shars tools into two large tool chests, and it looked like I had purchased inferior quality equipment.

Personally, I would advise new machinists such as myself to adopt a policy of only purchasing higher quality equipment. If this were happening with a Mitutoyo micrometer and a Starrett gage block set, it would probably be a different conversation.


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## benmychree (Jan 17, 2020)

projectnut said:


> I go back to the last 2 sentences in my previous post.   "In this incident the OP is "assuming" the micrometer is properly calibrated and the gauge block is in error.  It could very well be just the opposite."  Without a controlled atmosphere how can the OP be certain which component is causing the difference from the measurement stated on the block.  Simply handling the block long enough to raise the temperature a few degrees can cause the dimensions to change.  Given a micron is .000039" and tool steel expands at a rate of 12.8 microns per degree, it would take less than a 5* change (from the standard of 68*) in temperature for a block to expand .0001".  Any lint or even a finger print on either on the micrometer or the gauge block could account for the difference in measurement.
> 
> I agree with John York's assessment of the use of gauge blocks in a hobby shop.  Mine were originally purchased to setup a sine bar.  I must admit however I have been known to use them to check the accuracy of a micrometer.  I have a number of micrometers in the shop.  The newest were purchased in the 1980's.  The oldest date back to WWII.  Even the oldest ones are good to within a tenth.  That's close enough for anything I do.


My mikes date (for the most part) to the 1960s, when I bought them new, all Starrett, and are still accurate enough for anything that I do, I have checked them with "mike checks", and there is no visable deviation, some have 60 years of use on a daily basis and are still accurate.


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## erikmannie (Jan 17, 2020)

Point taken regarding clean hands and materials, temperature and humidity.

When I set out to buy welding equipment, I was advised to buy Miller. I did, and things worked out very nicely. I don’t know why I cheaped out when it came to machinist tools.

Like I said, I will use the Shars equipment while I am learning and saving up for Starrett, Mitutoyo, etc. and then keep the good stuff in the inspection room.


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## Technical Ted (Jan 17, 2020)

I always suggest that newer people buy good used tools. If you watch Craigslist, Facebook Marketplace or whatever you can usually find a retired machinist or tool maker selling their collection. You might end up spending a grand + or so, but end up with machinist boxes as well as some nice tools. eBay's prices are too high IMO. 

To help set your mind at ease, or to really make you disappointed, you can always send one of the tools you question to a calibration service and see if it passes. Good or bad you will find out the truth.

Ted


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## mikey (Jan 17, 2020)

benmychree said:


> A gage block set of 50 millionths accuracy (1/2 of a tenth of a thousandth) is quite at the low end of the totem pole so far as accuracy is concerned ...



True. To really test a tenths reading mic, you need gauge blocks that adhere to the 4:1 Rule so I would need blocks certified to 0.000025" to certify the mic. However, I am not certifying it; I'm just checking to see if it reads close enough for my shop and a 50 mil block will do that. I do adhere to the 5-point recommendation to be sure the mic is reliably reading at the level of my blocks so I'm okay with it at this level of accuracy. 

The problem for hobby guys is the "chicken or the egg" situation. Is the block off or is the mic off or is it both, or is it your technique, ratcheting/friction force, speed, etc. The best way to know is to send your blocks to a lab and have it certified, with the true reading noted for each block. Personally, I cannot afford to do that so I take the cheap way out. I put my mic in a stand, wipe and then hold each block with a microfiber towel and run through the 5-point process and if it passes, then good. I run several mics through the same process with the same blocks and if all of them read the same then I assume the blocks are pretty accurate. No, not perfect but it works well enough to give me confidence to use the tools, which is really all I want.

Working to the level of the mic, now that is another thing ...


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## chips&more (Jan 17, 2020)

I guess some of the folks here on the HM are making parts for NASA LOL.


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## mmcmdl (Jan 17, 2020)

Back in the day , our tools had to be inspected and calibrated every 6 months per the DoD contracts . Calibration was performed by inspectors on site who didn't have the nimblest of hands and feel . When we received our tools back , we all put them back into spec where they started out . I never liked lending tools out or having less qualified personnel messing with any of my tools .


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## erikmannie (Jan 17, 2020)

Technical Ted said:


> I always suggest that newer people buy good used tools...



Having learned the hard way, now I know! If you buy quality, you get quality.

I wonder if anybody is able to consistently work to the nearest tenth using an import mill and "econo-tools".


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## mmcmdl (Jan 17, 2020)

Not on any mill . Maybe jig bores or grinders .


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## erikmannie (Jan 17, 2020)

chips&more said:


> I guess some of the folks here on the HM are making parts for NASA LOL.


I just do this as a hobby. For me, the journey is the destination. I am at my happiest when I am in over my head. Much of what I have learned is from frustrating, time consuming and  wastefully expensive tribulation. The more difficult the project, the more I seem to learn.


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## ACHiPo (Jan 17, 2020)

middle.road said:


> File to size, Hammer to fit.


Paint to match.


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## mmcmdl (Jan 17, 2020)

That's how we all learn and it's what makes being a machinist fun and interesting . ( Unless you are only pushing a cycle start button on a cnc machine ) . Prototype , R & D , breakdown work …………….it's all fun . 

1 part = prototype
2 parts = a matched pair 
3 parts = production .


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## mmcmdl (Jan 17, 2020)

erikmannie said:


> .0107” block surely measures thicker than the .0108”



Erik , I assume you mean .1007 and .1008 ?


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## erikmannie (Jan 17, 2020)

mmcmdl said:


> Erik , I assume you mean .1007 and .1008 ?


Absolutely. My mistake.


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## mmcmdl (Jan 17, 2020)

I figured that , never seen blocks that small .


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## erikmannie (Jan 17, 2020)

So am I the only one kicking myself for buying inferior tools? I made a terrible mistake! Live and learn.


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## mmcmdl (Jan 17, 2020)

What makes the tools inferior ? Are they a tenth off or what ? I would say that unless you're setting up a metrology department you'll be fine . I sold all my block sets years ago . Didn't need them . If I need to set sine bars or plates , I now use adjustable parallels or a planer gage . Close enough for gubmint work .


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## westerner (Jan 17, 2020)

chips&more said:


> I guess some of the folks here on the HM are making parts for NASA LOL.


I bid a couple of them jobs. Sent in my "as-builts" and everything. Still ain't heard back.....


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## mikey (Jan 17, 2020)

erikmannie said:


> So am I the only one kicking myself for buying inferior tools? I made a terrible mistake! Live and learn.



Erik, please be a little more gentle with yourself. There are a lot of new guys in our hobby today that wouldn't be were it not for import tools. If your tools allow you to do what you want to do then who cares if it doesn't read dead on with a NIST-traceable gauge block? As long as it is consistent then that's what matters. 

Years ago, I made a pin to slip fit into a block that I bored. I was going for a slip fit but I actually wanted to have an air bearing fit, just to see if I could do it. I got that fit and I was really happy! Turned out that the mic I used to read the OD of the pin and the telescoping gauge used in the bore was off calibration and I had to adjust the collar on the mic but _the pin still fit in that bore_. This was many years ago and it was an old Helios mic; still have it, still use it. 

So sure, buy better tools as you are able to afford them but don't beat yourself up for buying those tools. Use them.


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## erikmannie (Jan 17, 2020)

mmcmdl said:


> What makes the tools inferior?...



Inferior to Starrett, Mitutoyo, Brown & Sharpe, etc. I just wish that I had spent the $2,500 on a smaller number of the proven winners, if for no other reason than not having to second guess the equipment.

Rather than bashing any particular country for importing what is often junk, I just want to say that we had Starrett, Mitutoyo, etc. at school, and the tools were a pleasure to work with.

Of course, I will be moving full speed ahead with the equipment that I bought & I will report how it is going on the forum.


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## mmcmdl (Jan 17, 2020)

Years ago , we didn't have many choices as to which brands were available , and they were all expensive . Making $3.11 an hour starting out as an apprentice , half the $$$ I made went back to the company . We had a tool loan program set up for the young guys starting out . It was Starrett , B &S , Mits , Fowler , Lufkin maybe a few more . The " oldtimers " steered you in the right direction as to what quality meant .

There are plenty of used tools out there though of top quality as many machinists are retiring or expiring these days . Hit the yard sales and flea markets when you become dis-satisfied with the tools you own . You'll probably find that nice sets of Starretts go for less than the new imported stuff .


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## ttabbal (Jan 17, 2020)

Having used import and Mitutoyo and Starrett... They have their place. The big names have a nicer fit and finish, smoother action, better feel.. And yeah, more accurate from what I can tell. I think it's more that the feel is more consistent, so it's ME that is more accurate at least some of the time. 

Out of curiosity, I calibrated 3 mics to the same standard, being as careful as possible. New mitutoyo digital, tenths reading mechanical Starrett, and a Harbor Freight digital. I measured a few things around the shop with each a few times. Got more consistent readings with the big names, drifted a couple of tenths with the HF. That's more accurate than I am on the tools, plenty good enough. I use the HF for times I think I might drop it and to get within 10 thou or so. Switch to one of the others for final size and inspection. Or when the HF eats the battery I swear and grab a mechanical.  The Mitutoyo has never left me hanging like that, I don't know how the HF manages to eat batteries so fast. 

Keep in mind that most of what you do in a home shop is +/-0.005 or more. Even HF calipers can measure that tolerance.


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## erikmannie (Jan 17, 2020)

ttabbal said:


> ...Keep in mind that most of what you do in a home shop is +/-0.005 or more...



I can definitely hit +/-.005”!


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## erikmannie (Jan 17, 2020)

I do have the option of listing my Shars tools on eBay while I use them, and then using the net proceeds to get good stuff.

This wouldn’t cost me anything except my time. If they never sold, I could just keep them.


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## DavidR8 (Jan 17, 2020)

Well do let us know if you list them. 
I’m still building up my inventory of metrology gear. 

Sent from my iPhone using Tapatalk


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## erikmannie (Jan 17, 2020)

DavidR8 said:


> Well do let us know if you list them.
> I’m still building up my inventory of metrology gear.
> 
> Sent from my iPhone using Tapatalk



I will get them up Sunday & Monday. What is the forum friendly way to do this? I saw a subforum where members who have contributed to this fine forum can sell stuff. I should give the people here first dibs, including trades for what I consider higher quality equipment.

I definitely don’t want to tick off the powers that be.


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## mmcmdl (Jan 17, 2020)

erikmannie said:


> members who have contributed to this fine forum can sell stuff.



I believe this as a correct statement .


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## middle.road (Jan 18, 2020)

erikmannie said:


> I will get them up Sunday & Monday. What is the forum friendly way to do this? I saw a subforum where members who have contributed to this fine forum can sell stuff. I should give the people here first dibs, including trades for what I consider higher quality equipment.
> 
> I definitely don’t want to tick off the powers that be.


Give this a try before giving eBay your $$$$, Subscribe to H-M and try to sell them here in the classified area.
We'd all benefit from that.


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## Chewy (Jan 18, 2020)

*erikmannie, *I have been wondering since this thread started, what is it that you are machining down to a couple of tenths? You state that you are new to machining. You just joined the forum.  You bought all this inferior equipment and now want to sell it. In your first post you state that you can machine down to 3 tenths. What kind of machines do you have?  Do you have some really good machines tricked out by Richard King?
I think all of us would like to know the details of your shop, equipment and projects. Why do you need such great accuracy?  I can see if you are maybe making some assemblies for a 787 or maybe a U2.  I have some grownup Boy Scouts who do machine down to 1-2 tenths all day.  Or should I say that they babysit some machines north of a half mill $ making highly critical aerospace parts.

I have B&S, Starrett, Mitutoyo, Igaging & Shars..  Just got a brand new $33 Shars digital mic today. My Starrett gauge block set was used when I got it 30 years ago.  When I pull out all the different mics and check a block, they all seem to read the same.  This is the second Shars digital. The main thing is that the readings are repeatable.  When I do ten readings over ten minutes at 68 degrees and then get the B&S to read the same, than to me that is good. I will admit that I have never sent any of my stuff to NIST to be rechecked.

Please let us know what you are machining.  Charles


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## Technical Ted (Jan 18, 2020)

Here's one way to think about it. When craftsmen of years passed used calipers and a steel rule, do you think they were concerned about tenths??? The mating of parts and the fits are what is important, regardless of how you measure them. Measurements come to be more important when making something to a drawing for someone else. Geez, I don't even think I can consistently hold a tenth on my surface grinder!   

Sounds like you are a perfectionist, and a lot of us are, but as you gain experience you will learn a hobby machine shop is not a perfect place. The closest we come is figuring out ways to alter things, to make parts we've made mistakes on while machining, work with mating parts as designed, rather than throwing them in the scrap pile! 

Ted


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## erikmannie (Jan 18, 2020)

Chewy said:


> ...Please let us know what you are machining...



I am trying to develop plate armor for the inside of tires for an electric bike.

The material for the plates is .045” Grade 5 Ti. The prototypes and fixtures are mild steel.

These bikes can travel up to highway speeds, so it can be a matter of life and death if the wheel assembly is out of kinetic balance. Safety always comes first.


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## erikmannie (Jan 18, 2020)

Technical Ted said:


> Here's one way to think about it. When craftsmen of years passed used calipers and a steel rule, do you think they were concerned about tenths??? The mating of parts and the fits are what is important, regardless of how you measure them. Measurements come to be more important when making something to a drawing for someone else. Geez, I don't even think I can consistently hold a tenth on my surface grinder!
> 
> Sounds like you are a perfectionist, and a lot of us are, but as you gain experience you will learn a hobby machine shop is not a perfect place. The closest we come is figuring out ways to alter things, to make parts we've made mistakes on while machining, work with mating parts as designed, rather than throwing them in the scrap pile!
> 
> Ted



I try for perfection, never achieve it, and hope that the results are good enough.

I have found that the imported economy products, while easy on the pocketbook, can make a difficult project more difficult than it needs to be. The Taiwanese products seem to be good enough for my purposes. China, not so much.


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## erikmannie (Jan 18, 2020)

middle.road said:


> Give this a try before giving eBay your $$$$, Subscribe to H-M and try to sell them here in the classified area.
> We'd all benefit from that.



I see that becoming a Gold Member will allow For Sale privileges. First I have to come up with $625 for more machining school tuition. I think I can have money for a gold membership in about a week.

I won’t advertise any of these Shars tools for sale anywhere else until members of this forum have had a good, long chance to get what they want.

I am shouting from the rooftops that I do not recommend cheap econo-tools. Don’t do it!


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## Liljoebrshooter (Jan 18, 2020)

If this inferior measuring equipment bothers you that much,  throw it in the dumpster and order name brand stuff from a reputable dealer.    
Obviously there is a big difference in the budgets of us hobby guys.
Joe Hynes


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## erikmannie (Jan 18, 2020)

Liljoebrshooter said:


> If this inferior measuring equipment bothers you that much,  throw it in the dumpster and order name brand stuff from a reputable dealer.
> Obviously there is a big difference in the budgets of us hobby guys.
> Joe Hynes



Only after I put my entire mill & lathe order on a credit card did I hear that “You are going to spend as much or more on the tooling that you did on the machine.” I thought, “How will I afford that?”.

When I looked at the price of Starrett and Mitutoyo products, I realized that buying those would actually put me out on the street.

Machining is an expensive and rewarding hobby!


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## projectnut (Jan 18, 2020)

As Mikey said, step back, relax a bit, and make long term plans as to what you would eventually like to have as far as metrology tools are concerned.  You don't have to start with top of the line tools.  Working to the tenths takes time and experience to achieve.  It's a steep learning curve that isn't going to be accomplished overnight, or in a few months for that matter.  The tools you have should be more than sufficient while learning, and will in all likelihood be used many years into the future.  I personally use less expensive (cheap) Harbor Freight calipers for measuring general roughing cuts.  I have more expensive Mitutoyo and Starrett brands on the shelves, but tend to use the cheapies in most situations.  They are accurate enough, and I wouldn't be crushed, or out a ton of money should I do an oops, and bang one up.

When I purchased the majority of my tools there was no such things as Shars, Travers, Penn Tool, or anyone else for that matter that dealt in imported tools.  Consequently tools were more expensive, and took far longer to accumulate what was needed given the wages were a fraction of what they are today.  While the import tools in some cases seem to be less desirable than older established brands they aren't necessarily so much less accurate they aren't acceptable.  

I do believe there is some level of snobbery that goes along with the brand(s) of tools people want to have in their inventory.  To that point I've seen people who call themselves machinists have thousands, if not tens of thousands of dollars of high end tools that they have no idea how to use.  In some cases the lack of skill was so bad a top shelf machinist could do a better job with a 6" scale than some could do with a micrometer that measures down to the tenth.  Don't let the brand name alone discourage you.  With time and effort your skills may develop to the point you could be one of those that only need the 6" scale.  If you do develop to that point you'll have a toolbox full of expensive dust collectors.

Assuming in this incident it is your micrometer that's actually off by a tenth or so.  In the real world it's such a minor difference it won't effect 99+% of the work you do.  At this point on the learning curve you at least have tools that will allow you to measure within reasonable parameters.

As a point of  reference our local technical college has switched to using mainly Shars brand metrology tools.  They find the tools to be accurate enough for learning purposes, and far less expensive to replace should they be lost or damaged.  Keep in mind these tools are being used by students that aspire to become professional machinists, or tool and die makers.

The truth be known I have a number of Shars tools in my shop.  They include gauge blocks, a broach set, 123 blocks, several sets of parallels, some 5C collets, lathe tool holders, milling saw arbors, and others.  I could have purchased more expensive tooling, but didn't find it necessary.  If I feel the need to have high end name brands on all my tools I can always use a magic marker, or Sharpie.


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## Chewy (Jan 18, 2020)

*erikmannie,* If you are at all serious about what you want to do, let's analyze the process. 

1.  The tools and equipment that you have may already be sufficient to make a prototype.  Think Wilbur & Orville in a bicycle shop.  Your "inferior" tools are light years ahead of what was available at the time.
2. Make a good CAD drawing.
3. Hire a lawyer.  You need to check for existing patents and also what DOT requires to be allowed on the road.
4. Get an engineer to certify your material properties.  Flexibility being very important.  Tires are only round off the vehicle. He should also be able to advise thickness and maching tolorences.
5. You can start machining the prototype.  You will need to work within the limitations of your machine.  To prove the feasibility of the idea, machining to a thousand or 1/2 thousand may be fine. Other option is to find a company that has the capability to make the prototype for you.  The next option is to spend some really serious money to get machines with the tolerances you want.  At the least you will need a good surface plate and dial indicators to check the machined item. Or one of them fancy digital touch probe measuring machines.
6. Find a really, really rich investor or business to partner with. A business
7. Home-brew test the tire to see if it works at all.  Riding down the street isn't a good idea.  If the prototype fails you may need an engineer to determine why and suggest alternatives. If the tire lives, make a couple for destructive testing.
8. Have a lab test and certify the results. DOT may require this.
9. Get a ton of insurance and farm out the manufacturing to a reputable company or buy the equipment and start your own.  Better still, partner with a company and just get a royalty.

Can you do? Absolutely! A lot of work and headache.  The reward is that you may become a millionaire if your idea takes off.  Who knows,we might be bloging with the next Elon Musk! However, if the machines you have can't handle the material you specified down to say, one hundred thousands of an inch, then buying all the micrometers and gauge blocks to measure one ten thousands won't really get you any where.  You might really need one ten thousand accuracy for public use, but I would end up there, not start there.

Good Luck and keep us posted!  Charles


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## Winegrower (Jan 18, 2020)

A few months ago I purchased two Kennedy boxes full of machinist tools (there is a thread on this) which included micrometers covering 0 to 4”, 0 to 6” depth micrometers, 0 to maybe 8” inside micrometers, etc.   I had a Mitutoyo digital caliper and Mitutoyo 1” digital micrometer reading to 50 millionths, and a couple of HF $15 digital calipers.

There were a couple of 1” calibration standards, so I checked everything against everything...oh, including about a half dozen 1-2-3 blocks.   I was very surprised to see that each tool met what I, at least, would expect its accuracy level to be, for digital plus or minus a count, and analog same, plus or minus one of the smallest readable unit.   So cheaper stuff i would believe to about +/- .001 level stuff, some analog are the same, and the best digital would be +/- a tenth.   I found more variability in my ability to make repeatable measurements than in the instruments, I’m embarrassed to say.

So my practice now is to use the cheapest tool with the required accuracy.   Those HF units get a lot of use.


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## erikmannie (Jan 18, 2020)

Chewy said:


> *erikmannie,* If you are at all serious about what you want to do, let's analyze the process.
> 
> 1.  The tools and equipment that you have may already be sufficient to make a prototype.  Think Wilbur & Orville in a bicycle shop.  Your "inferior" tools are light years ahead of what was available at the time.
> 2. Make a good CAD drawing.
> ...


I am 53 years old and all I like to do is go to school and work in my shop. I have a good union job (I work for UPS at the Oakland Airport) that will allow me to pay my bills, go to school and work in my shop for the rest of my life.

I have never had any interest in sales, marketing or becoming wealthy. If I were wealthy, I would still work at the same job, go to school and work in my shop.

My tire armor idea is very much open source. I hope that somebody does bring it to market, but it won't be me because that could take me away from my classes or shop.

My prototype steel plates do the job for my purposes; I only need to find a more elegant way than duct tape to attach the plates to (the inside of) the tires. The plates move independently in all axes. I don't mind fabricating the plates (in fact I enjoy it), but mass production of the plates would call for a streamlining of the production process. 

I will start a thread on this when I have time; until I do, here are some important considerations:
(1) Great fitup makes the welding go a lot faster and easier,
(2) .050" Grade 5 Ti in precut 5" X 5" squares is not expensive because you can buy second hand drops. The ERTi-5 is expensive, and of course a lot of Argon is used.
(3) I use a hydraulic press to bend the material,
(4) I have only tested these at 19-20 psi tire pressure, and
(5) There are many simple ways (e.g. powder coating) to protect the material from cutting the tube (if using a tube) or tire.

Here are the CAD drawings for a single plate for a 26" X 5.05" tire. If anybody is interested, you may adopt the idea as your own.


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## erikmannie (Jan 28, 2020)

I did additional testing, this time inside my 70 degree F home with Starrett 0-1” and 1-2” micrometers in addition to the Shars digital electronic mikes mentioned in the OP. This time, the Shars gauge blocks tested fine in relation to the Starrett mikes. 

I think the Shars digital electronic mikes were the source of the confusion. So now I use the Shars mikes for roughing cuts.


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## Nogoingback (Jan 28, 2020)

I think there's another reason for having quality tools besides the fact that they are more accurate or do the job better.
A good tool is a pleasure to use, and makes the task more enjoyable, which, after all, is why we have hobbies.  I imagine all of us have tools that we particularly enjoy using:  perhaps passed down from a relative, because they just feel "right"
in the hand or because we've used them for years and enjoyed making things with them.  In my experience, poor quality
tools rarely fall in that category.

If you aren't happy with the Shars mics, for whatever reason, get rid of them and buy something that you'll enjoy.
There are lots of quality tools in good condition out there at good prices.  You don't need to buy new or spend a huge sum of money.


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## erikmannie (Jan 28, 2020)

Nogoingback said:


> I think there's another reason for having quality tools besides the fact that they are more accurate or do the job better.
> A good tool is a pleasure to use, and makes the task more enjoyable, which, after all, is why we have hobbies.  I imagine all of us have tools that we particularly enjoy using:  perhaps passed down from a relative, because they just feel "right"
> in the hand or because we've used them for years and enjoyed making things with them.  In my experience, poor quality
> tools rarely fall in that category.
> ...


Great points. After I posted that, I sat down again with the same materials and played with them for a few hours. My tentative conclusion was that these Shars mikes would be able to get me to a thou at best, and the gauge blocks seem to be accurate to about 5 tenths. This is just my experience.


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## mattthemuppet2 (Jan 28, 2020)

erikmannie said:


> I am trying to develop plate armor for the inside of tires for an electric bike.
> 
> The material for the plates is .045” Grade 5 Ti. The prototypes and fixtures are mild steel.
> 
> These bikes can travel up to highway speeds, so it can be a matter of life and death if the wheel assembly is out of kinetic balance. Safety always comes first.



I wouldn't sweat the metrology stuff too much to start with. In my experience you find out as you go along which aspects of metrology you're deficient in and fix those as they come up. If you're struggling to get repeatable bore measurements and bearing press fits, you get better telescoping gauges or step up to bore mikes. If you're working to tenths on shaft diameters, you get a machinist level, lathe test bar and maybe a tool post grinder. It just depends.

As for the project, that sounds like something for the Department of Defense, like for a Mine Resistant Armoured Personnel Carrier! I can't see motorcyclists (or ebike cyclists) being all that keen on the extra weight of Ti plates for what is likely to be a marginal improvement in puncture resistance over steel or aramid belted tires. Just by rough calculation those plates come out to around 900g per tire. That will have a significant effect not just on acceleration/ deceleration but also on the gyroscopic effect in corners. I ride an ebike around 9000 miles a year, every working day, and I get perhaps a puncture every 3000 miles. On really crappy rarely cleaned roads. It's a neat engineering project for sure, just can't see much of an application for it.


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## erikmannie (Jan 28, 2020)

mattthemuppet2 said:


> I wouldn't sweat the metrology stuff too much to start with. In my experience you find out as you go along which aspects of metrology you're deficient in and fix those as they come up. If you're struggling to get repeatable bore measurements and bearing press fits, you get better telescoping gauges or step up to bore mikes. If you're working to tenths on shaft diameters, you get a machinist level, lathe test bar and maybe a tool post grinder. It just depends.
> 
> As for the project, that sounds like something for the Department of Defense, like for a Mine Resistant Armoured Personnel Carrier! I can't see motorcyclists (or ebike cyclists) being all that keen on the extra weight of Ti plates for what is likely to be a marginal improvement in puncture resistance over steel or aramid belted tires. Just by rough calculation those plates come out to around 900g per tire. That will have a significant effect not just on acceleration/ deceleration but also on the gyroscopic effect in corners. I ride an ebike around 9000 miles a year, every working day, and I get perhaps a puncture every 3000 miles. On really crappy rarely cleaned roads. It's a neat engineering project for sure, just can't see much of an application for it.


Recently, when I taking 3+ hours to install 28 prototype plates in a fat tire, I was thinking "*I would so much rather be working on my lathe right now*". Today, I spent most of the afternoon on the lathe (so fun!), and I was thinking "This is so much better than installing plates in a tire".

So there ya go. I am going to put the bicycle tire plate armor project on the back burner indefinitely and do what I like which is working on machine tools and welding. At some point, a guy just wants to have fun.

I'll bet that most people here like to spend time making stuff in their shop.


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## pontiac428 (Jan 28, 2020)

When I first started out, I needed some measuring tools to keep at the bench while running parts.  I bought a set of 0-6" individually boxed Chinese micrometers with the odometer digits that read thousandths, and a vernier barrel for tenths.  The tools were smooth and worked pretty well.  I verified calibration with a span of gauge blocks to within .0001-.0002 using the torque clutch on the thumb wheel.  I did the same for my Chinese dial calipers.  The tools tested good.  Now, twenty something years later, I'm replacing those mics with Suhl, Jena, and Helios pieces (there's a theme there).  I am under no misconceptions that they will _measure_ better, they just feel better.  So I've spent more on good used German calipers than I did on my new, perfectly good Chinese ones, and all I really have gained is a better, seemingly more consistent feel, and in some cases (Suhl) the calipers have big, easy to read heads.  

Now, I've never used Shars' measuring tools, but I have a pile of Shars stuff that I've been very happy with across the board.  Shars was great before the tariffs, now it's pretty good even at a higher price.  I don't think they have much more headroom to charge for imported, tariffed steel before people find other, more equitable ways to buy what they need.  But at the end of the day, Shars stuff is definitely useable, and we're their market.  I think the stuff you've already bought will serve you well if you can find confidence in it.


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## westerner (Jan 28, 2020)

pontiac428 said:


> But at the end of the day, Shars stuff is definitely useable, and we're their market. I think the stuff you've already bought will serve you well if you can find confidence in it.


This is, after all, the HOBBY machinist site. If you are being browbeaten to produce parts to NASA spec in production level quantity, this is probably NOT your site. 
I love the atmosphere here. "Practical Machinist", not so much. Mostly due to the fact I AM A HOBBY MACHINIST.


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## erikmannie (Jan 29, 2020)

westerner said:


> This is, after all, the HOBBY machinist site. If you are being browbeaten to produce parts to NASA spec in production level quantity, this is probably NOT your site.
> I love the atmosphere here. "Practical Machinist", not so much. Mostly due to the fact I AM A HOBBY MACHINIST.


This forum is indeed very helpful and friendly. I understand that Practical Machinist doesn’t even allow people to discuss Asian machines (my machines are Precision Matthews).


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