35 buck Chinese Machinist's Level overhaul and cralibation (!)

[DIYSwede]

No pause for the wicked:
Needing an accurate and repeatable Machinist's level for some time, but being a Swedish cheapskate,
I didn't particularly want to part from the 100-150ish bucks necessary to get one.

-Lo and behold: there IS actually one to be found for 35-ish USD at a Chinese web vendor site!



-Now, is this to good to be true, you may rightly ask?

-Well, this might seem simple and straightforward - but wait 'til I've explained!

First: It IS within stated specs in the pic above, confirmed relatively via a 1 m long DIY sine bar & feeler gauges:
2 hundreds of a mm (per div) in 1 meter is darned good at that price, equals 1 in 50 000 (any measurement system).
You really have to wait for the bubble to set, and even my weight shifting on the
(wood on concrete) floor below the bench influences it...

Machining of the 4 x 1 x 1" tool steel house, the paint choice & job + the fixation of the tiny, coarse vial on top is a bit sloppy,
but its foot with the V-groove is excellently ground - checked by its consistent bluing from my surface plate.
There were also some ill-fitting black rubber "butt-plugs" at the tool ends.

Todays assignment was to try out the DIY 3-point absolute leveling system I've kludged together for my surface plate,
taping up an angle to rest the level against: Check, twist the level, check and turn knobs. Rinse and repeat - Simple, right?

Started out to measure, soon to find that the calibration screws weren't even close enuff for comfort.
There's 5 of them, two horizontal pivot set screws at the tiny vial's end, and three at the other, 120 degrees apart,
for vertical (and side - if ever needed...) alignment. The latter ones didn't have the travel enuff to zero it out. Dang.
So - opening up and checking for a remedy I found all this inside:



(Yeah - I've turned the vial tube over ends...)
The vial's fitted (by something yellowish, looking like molten sulphur...) inside a 3/4" steel tube (non-stainless...)
within the house's 20,5 mm bore (also rusty where the paint haven't run), so given the two horizontal pivot points,
the 3" long vial tube should have a plentiful movement of +/- 0,7 mm at the other end, right?

NOTE: I'm NOT sniveling over the lousy turning, poor grinding or the rough hacksawing of the tube, right?

This tool, though produced with the immense possibilities of achieveing an excellent value for money, misses out a bit:



This end view of the vial tube would've been totally uncalled for, hadn't it been for the 2 grooves' horizontal positions.
I took the liberty of Sharpie-extending the grooves' angles inwards, to show their "peripheral offset from intention"...

Given the hacksawed grooves' offset downwards from center, the tube's top rests darned close to the bore,
thus eliminating the small nudge needed to zero it out, as the tube's other end jams to the bore's ceiling.

What to do?
1) Turn the entire tube clean a few thou, drill 2 tiny holes for the pivot screws at the right spots. Rustproof. Remount. or:
2) Fit entire house in 4-jaw, bore out hole with a compound taper to accomodate more travel. Rustproof inside.

Both methods having slight disadvantages: Mounting the vial tube in a collet and turning it feels kinda anxious,
but OTOH hard-turning the housing feels a bit overkill.

"Work order" as of now:
1) Turn/ clean up the vial tube, radially drill two holes for set screws at the right places lengthwise and centered. Rustproof.
2) Wrap emery round a tight-fitting wooden/ plastic dowel, run round and down the house's hole. Rustproof.
3) Remount the shooting works and cralibate it. Enamel the screws.
4) Rejoice in all the achieved cheap results, and use for intended purposes.

To be continued...

[Toolmaker51]

Excellent description of the issues and remedies. These short Chinese levels impersonationate very nice Japanese made product and appear designed same; without full comprehension of things like the calibration screws. DIYswedes reworking addresses them all.
The Japan levels were on hand during my assignment in Reno, NV. I just went ape over them, being so compact. The price of the copies hollers out "Get Two!" which really makes proper leveling go far quicker.
He also mentions sensitivity they register as he moves about.
Hint. On .0005 or finer levels, contact with hands, even drafts of air or breath will do that, via expansion/ contraction of the housing.

[DIYSwede]

-Chucked the vial tube in the 4-jaw for an assumed quick cleanup.
20 mm mystery metal tube with a sturdy 2 mm wall thickness - how hard can it be?

Clocked it in, showed that the reason for the horrendous original grinding job probably
was that it's been ground lengthwise, top and bottom to achieve better adjustment clearance.

It would then have been just really convenient if they'd cut the two pivot screw slots correctly,
(i. e. 180 deg apart & horizontally) to make full use of the 3 adjustment screw's clearance at the other end.
Now when that isn't an option, I'll eventually have to set up my (nearly finished) toolpost radial drill,
and centre drill a pair of tiny dimples/ holes for the pointed pivot screws to sit in.

Back to tonight's work: As the top and bottom parts of the tube has been ovally ground,
I offsetted the tube 0.25 mm (10 thou) in the 4-jaw, set up a shear tool and started:



Pic shows 2nd run, with the left, already finished half of it mounted in the chuck.
Took off half a mm (20 thou) total with the shear tool for best finish of the crummy steel,
which just about cleaned it up. Ran low rpms and slooow feed to avoid chatter.

Remains to rechuck and indicate it, drill the two pivot holes, add som rust primer to the vial tube,
cleanup the tool's inner bore and rustproof that as well. Mount and "cralibate".

More to come.

[DIYSwede]

Not so much going on with this since I've had a busy semester startup at my Uni job.

But to get the vial tube properly hinged on the two set screws within the tool tube,
there's a pair of tiny holes to be drilled pretty exactly: both lengthwise and peripherally.
And as I'm not yet have a proper chuck indexing system in my walk-in closet workshop,
I had to wing something Q & D together, to align my 4-jaw horizontally:



Just a piece of extruded profile from a crashed hard drive, milled to 82,21 mm height.
Then crudely cut sides and notch to allow for the bottom jaw and up to max 60 mm pieces in the chuck.
Snaps under and locks (thru the foot's springiness) the 4-jaw at 90 deg intervals:



Then, with the toolpost drill, centre drill the tube at just the right place:



Next: Mere rust prevention paint job, assembly and "cralibation".

[DIYSwede]

Title sez it all - overconfident that my proper drilling yesterday would suffice,
for finally getting the vial to zero out.
I hadn't considered the other Unknown Chinese Bozo fitting the vial in the tube.

The darned thing isn't even fitted centrally in the tube, rather just thrown in,
and covered up with the yellowish plaster or whatever that is.
Don't really want to make a full autopsy and refit in fear of breaking the darned vial...

Tonight's tryout shows I need to take the bore's bottom a further 20 thou down,
just to get in the ball park, and then some.
Though my surface plate's new Q&D adjustable feet works just great...
Just chuck the level's house in the 4-jaw, offset it 0.25 mm-ish and bore it out...



-It surely takes some persistance, methodology and ingenuity to stay cheap,
and finally get these "assembled kits" from overseas to work.

Somebody eager to post recommendations in buying well-renowned, expensive and US made brands instead -
you should really contain this urge, as no real, Cheapo DIY Machinist would ever follow your advice,
nor fold over such an interesting and rewarding challenge like this!
All the money we thus save, we immediately invest in other cheap tools-to-become-projects, see?

[Toolmaker51]

Lol DIYSwede. I'm convinced toolmakers of various experience/ different statures rework inferior tools all the time. Achieving setups for a one-off project teaches creativity and forethought. When you get down to it, that is what separates a machinist from operator.
Buying first rate has some satisfaction, but less than applying process remedies to cheapo facsimile tools. I have a good precision level, a rescue as well. Not the complications of yours though.
I like your "assembled kits" labeling. Another that really entertains me is "_________ shaped object". Insert noun of choice. First I recall, someone derided an import lathe full of faults, with coup de grace of "lathe shaped object".
Seems long ago, but tickles me still.

[mklotz]

I like your "assembled kits" labeling. Another that really entertains me is "_________ shaped object". Insert noun of choice. First I recall, someone derided an import lathe full of faults, with coup de grace of "lathe shaped object".
Seems long ago, but tickles me still.

It's a little known fact that SPAM stands for "Stuff Posing As Meat".

[DIYSwede]

Thanks Toolmaker 51 & Marv for pitching in.

Long story short:
My hindsight always has 20-20 vision, and I really should've stayed off trying to correct the vial's position within the tube...
"I'll just" was the inspired thought of the moment last night, by dissolving the fixing cement with an acetal acid solution,
carefully working the vial tube free to refit in its intended, proper place.
The flat, short end of the vial worked like a charm, (yup - you all already know what'll come...),
and the other deeply set, molten neck end showed promising results, just 'til I heard a small crack and felt a chemical smell...
-Any of you guys having tips on how to refill and seal a vial with a broken-off tip?

It really is a bit like gambling - each time you run the high risk of ruining everything in pursuit of "just fixing" that tiny fault.
Oh well, apparently at least ONE of us HMT posters can't be instantly successful each and every time, right?

I'm not sniveling (nor asking for pity or compassion), but it seems like my very first entry here:
Repeat Reading Gage - DIYSwede's "Cheap-O-Meter"
were the best (so far) - I've just gone downhill from there...

The everyday trudgery of a cheapskate machinist is a blessing in disguise, so I'll be back.

[DIYSwede]

Progress in this Bozo's repair is slow, and has (at least to me) to be, as I don't want to botch it entirely.
I have to free the vial from it's cemented position within the tube, remove its fluid content,
replace with the right amount of proper fluid and reseal the vial's broken tip. Reset in tube.

Thus some appropriate research is called for:
1) What refill fluid to use? (Mineral spirits, methyl- or isopropyl alcohol?)
2) Permanently (again!) sealing off the vial. Flame melt (risking shattering the vial) or "glass cement" (might not properly cure or seal)?
3) Properly and safely remount in tube. (Bentonite clay and water glass cement whilst holding vial true in tube...)

Some findings of mine might be of interest to other HMT:ers as Starrett themselves provided som info to a poster in this thread:
OldTools Archive

[DIYSwede]

I've returned to this project after all the honey-dos:

Broken nib in vial, fluid gone, and vial finally carved out of tube:



So, to "just finish off": Refill vial, seal it, set permanently in tube, reinstall & calibrate in level housing.

1) (Diethyl) Ether seems to be the liquid of choice for precision levels, probably due to its low freezing point and low viscosity.

Problem is that ether is hard to get for us mere mortals nowadays, so I'm considering getting a can of motor starter fluid,
and spraying that liquid* into a test tube enough to cover the vial, seal off the test tube and cycling that to and fro the fridge,
thus making the liquid work itself into the tube by thermal expansion/ contraction.
* >2/4 pentane, >1/4 ether, <1/4 acetone (and propane drive gas) from the MSDS - but I guess that'll be OK...

2) Seal off vial by super epoxy, (as the nib is too tiny for remelting the glass w/o risking cracking the vial)
put in fridge a few days to lower the internal vapor pressure while the epoxy is curing.

3) Reseat in outer tube by plaster of paris (they boldly used molten sulphur as a setter in the factory...).

Feel free to pitch in with thoughts on my choice of fluid, sealing and setting methods suggested above!

Thanks in advance

Johan