UNIMATS ARE NEAT BUT???

[Ulma Doctor]

need or want to brag about how many decimal places we work to???
temperature fluctuations would surely affect anything made to sub-tenth tolerances.
unless you're producing, and the metrology is in a temperature constant environment , you are performing superfluous gymnastics.
with all due respect, i agree with precision, but what is attainable by mortals is often like fishing stories.

my SL1000 has .002" resolution on the dials, kinda hard to turn to .0001" like that without help from an indicator

 

[Pylonracer]

need or want to brag about how many decimal places we work to???
temperature fluctuations would surely affect anything made to sub-tenth tolerances.
unless you're producing, and the metrology is in a temperature constant environment , you are performing superfluous gymnastics.
with all due respect, i agree with precision, but what is attainable by mortals is often like fishing stories.

Not bragging at all, I am just trying to show what is possible with a little care and some equipment bought off of Ebay.

The problem for guys like you is that you always talk of temp differences etc. but if you are turning to fit some other part and that is along side and in the same environment then that is what matters. Like wise with the metrology equipment.

My workshops do not see extremes of temp, it would be unwise to try and do precision work in a freezing cold or very hot workshop but also keep in mind these components are very small so the differences in sizes by thermal expansion are just a few microns.

Like I said not bragging just trying to enlighten what is possible for way less than a $1000.00.

Yes 0,002" dials, no problem to take tiny cuts, back to machining school for you Sir.

Quick to jump to conclusions, did you read what I said about winding on the cut using the topslide at 1 degree.

It is absolutely critical to have super-sharp tools though.

Of course, the other thing when talking about CTE is the massive difference in expansion with different materials.

 

[Pylonracer]

That is 0.000,078"
Most modern lathes only 0.000,1"
I have own a Tool makers lathe {Mori Seike} the was under 0.0.000,05" .
How close do you want.

Dave

FYI
It would be hard to find someone that owns the equipment to measure that close too.

Probably the other way around with the imperial to metric conversions.

0.0001" equals 0.0025mm

So my 0.002mm out of round is two tenths of a thou, that is not crazy accurate, a imperial 0.001" micrometer will easily measure to half thou and better with care, just look at how far it is in between the graduation lines.

When I was in engineering training school (16 years old) the instructors said to us one day, what did we think the most accurate that we could measure with a rule, we all said 1/64" as that was the finest that our rules went to, they said do you think that you can see half way between the 1/64" graduations? we said yes for sure, they said well you are measuring down to less than 8 thou in that case, they had a point. We had eyes like hawks in those days, no exposure to computer screens and the likes.

Your tool makers lathe figure is way better than what I am talking about.

1 micron Tesa micrometer bought off of Ebay for around $100, beautiful.

 

[Ulma Doctor]

Not bragging at all, I am just trying to show what is possible with a little care and some equipment bought off of Ebay.

The problem for guys like you is that you always talk of temp differences etc. but if you are turning to fit some other part and that is along side and in the same environment then that is what matters. Like wise with the metrology equipment.

My workshops do not see extremes of temp, it would be unwise to try and do precision work in a freezing cold or very hot workshop but also keep in mind these components are very small so the differences in sizes by thermal expansion are just a few microns.

Like I said not bragging just trying to enlighten what is possible for way less than a $1000.00.

Yes 0,002" dials, no problem to take tiny cuts, back to machining school for you Sir.

Quick to jump to conclusions, did you read what I said about winding on the cut using the topslide at 1 degree.

It is absolutely critical to have super-sharp tools though.

Of course, the other thing when talking about CTE is the massive difference in expansion with different materials.

View attachment 482854

I’m sorry if I offended you or anyone else. I’m not trying to convey that you were bragging.
I made a general statement about machinists in regards to their self-worth being tied to how many zeros they can place between a decimal point and a 1 or a 5.
I applaud your acquisition of a worthy machine for less than 1k.
I hope you enjoy the hunt!

 

[Pylonracer]

I’m sorry if I offended you or anyone else. I’m not trying to convey that you were bragging.
I made a general statement about machinists in regards to their self-worth being tied to how many zeros they can place between a decimal point and a 1 or a 5.
I applaud your acquisition of a worthy machine for less than 1k.
I hope you enjoy the hunt!

Thanks, the hunt for the tenths is great fun.

 

[ShagDog]

Thanks, the hunt for the tenths is great fun.

I agree. I don't need to do so for the kind of stuff I make; however, I make it my goal.

 

[Smithdoor]

A lot of model engines need accuracies better than 0.0005" in certain areas.

I mentioned 0.002mm which is right about a tenth of a thou but that was out of round of finished components.

Having said that I could turn down to tenth of a thou on a Unimat 3, cant the top slide around at about one degree off the spindle axis and wind your cut on with that angled top slide, also needs super sharp tools, diamond tools are best.

This photo is of a piston in an EMCO Compact 5, you can see that the yop slide is angled over by 1 degree. Works well.

View attachment 482823

Accuracies depends on the part of part you are working.
It like press fitting a ball bearing.
A small one may need less than 0.000,1 and a very large one is 0.001" . On other parts of same part can be ±0.002".
If very large ±0.050" working ships some parts can be greater.

Try this for size milling columns have to very tite or the building could till. This why NASA has tight tolerances no one wants a curve in rocket.

On some ag equipment you need very loose tolerance so sand does jam up everything.

Now most that has gone to college has had very little or no time on what tolerance to use.

Dave

 

[Smithdoor]

I’m sorry if I offended you or anyone else. I’m not trying to convey that you were bragging.
I made a general statement about machinists in regards to their self-worth being tied to how many zeros they can place between a decimal point and a 1 or a 5.
I applaud your acquisition of a worthy machine for less than 1k.
I hope you enjoy the hunt!

Trying to blame the machine again.
There is no hunt it just do the job right. A operator may time to get uses to lathe but he can maintain ±0.000,2" on most work.
If using a turret lathe this can be even closer.
Do not wast time on making ever part ±0.000,1" unless you are doing for fun.

Dave

 

[Smithdoor]

need or want to brag about how many decimal places we work to???
temperature fluctuations would surely affect anything made to sub-tenth tolerances.
unless you're producing, and the metrology is in a temperature constant environment , you are performing superfluous gymnastics.
with all due respect, i agree with precision, but what is attainable by mortals is often like fishing stories.

my SL1000 has .002" resolution on the dials, kinda hard to turn to .0001" like that without help from an indicator

Note to cut to 0.000,1" use compound for feed can turn to 11°
This give a finner feed
Lock cross slide so does drift

Dave

 

[skogkatt007]

It's amusing to view such a comversation.

I started out by saying in essence with extra work (and tricks) tolerances greater then the lathe specs are obtainable. The skill of the operator also comes into play. I severely doubt someone can hold a toleramce of .0001 on a Unimat (any model). Judging by the U3 I had, I doubt anyone could hold .0001 repeatedly.

But not all lathes are equal. The typical engine lathe is not made to the same specifications as say a Hardinge HLV-H. Or a Levin. Much more is capable repeatedly. The old Rivetts were reknowned for their accuracy. There was an article on the net over 20 years ago describing how a guy modified a Rivett 608 to cut 100,000 threads per inch. Creating what was called a diffrection grating. I imagine you can still look that up.

Is stuff like that doable on a Chinese 7 x 12? Go ahead and try. I remember a guy saying years ago it's nice when you can make 2 "identical" parts on a lathe. But with those you couldn't make 1!!!. I am not knocking people's machines. It's just that there is a wide variation in quality. And that's just the way it is. A very well made machine is capable of higher tolerances - repeatedly. The cheaper machines require more work/tricks/skill to achieve better results.