Working to Tenths with Economy Tooling

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
 
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
 
Chewy said:
...Please let us know what you are machining...
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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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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
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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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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.
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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!
 
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
 
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
Click to expand...

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!
 
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.
 
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
 
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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