I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from the
noodle factory, partly as an experiment, and ultimately to give to my 9 year old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). The random error of the 47257 seems to be
about 0.002", largely due to head looseness. I tightened the head gib, and the
error dropped to about 0.001", which is what HF claims. I don't know how well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as this
takes some force. The caliper came in a plastic case, and shipping damage was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a coating of
blackish grease, which easily wiped off. But still there was too much drag and
slip-stick. It turns out that the bar was precision ground but not polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly
filing away at the gib, which is brass. Not good, so I polished the grind marks
by hand with crocus cloth. This helped immensely. I suppose that crocus cloth
wrapped around a metal sanding block would do an even better flat polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery, but it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

You will find that not only is the Chinese caliper less accurate, they eat batteries at least twice the rate of a Mitutoyo.
Steve

"Joseph Gwinn" wrote in message ...
I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from the
noodle factory, partly as an experiment, and ultimately to give to my 9 year old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). The random error of the 47257 seems to be
about 0.002", largely due to head looseness. I tightened the head gib, and the
error dropped to about 0.001", which is what HF claims. I don't know how well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as this
takes some force. The caliper came in a plastic case, and shipping damage was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a coating of
blackish grease, which easily wiped off. But still there was too much drag and
slip-stick. It turns out that the bar was precision ground but not polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly
filing away at the gib, which is brass. Not good, so I polished the grind marks
by hand with crocus cloth. This helped immensely. I suppose that crocus cloth
wrapped around a metal sanding block would do an even better flat polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery, but it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

On Wed, 24 Feb 2010 09:05:40 -0500, the infamous Joseph Gwinn
scrawled the following:

I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from the
noodle factory, partly as an experiment, and ultimately to give to my 9 year old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). The random error of the 47257 seems to be
about 0.002", largely due to head looseness. I tightened the head gib, and the
error dropped to about 0.001", which is what HF claims. I don't know how well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as this
takes some force. The caliper came in a plastic case, and shipping damage was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a coating of
blackish grease, which easily wiped off. But still there was too much drag and
slip-stick. It turns out that the bar was precision ground but not polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly
filing away at the gib, which is brass. Not good, so I polished the grind marks
by hand with crocus cloth. This helped immensely. I suppose that crocus cloth
wrapped around a metal sanding block would do an even better flat polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). Pretty
smooth now.

You realize that a few days or weeks of use would have made it much
smoother, too, don't you? (Not near -as- smooth, but smoother.)


The manual says that the caliper requires a SR44 (silver oxide) battery, but it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

With all that time invested in the thing, that $30 HF caliper is more
costly than the eqivalent Starrett. Ironic, ain't it? snort

Nice job, BTW.

--
"Politics is the art of looking for trouble, finding it whether it
exists or not, diagnosing it incorrectly, and applying the wrong
remedy." -- Ernest Benn

Joseph Gwinn writes:

I just got a $30 Harbor Freight (item 47257) six inch digital caliper,

I have had nothing but success with these. I am still using the first one
from 2003 and it still holds +/- 0.001". Maybe they are not as good
lately.

Of course, I buy them on sale for $10.

More importantly, I test them in the store. Consider it field-level
quality-control testing. Take your gage blocks with you, and go through
the pile until you get the good ones, if there are any. The yokel store
clerks will be respectfully baffled at your metrology expertise.

I have a nice campaign souvenir advertising the local board of elections
supervisor elected official, who handed out free printed plastic sheet
rulers. Whoever printed these things applied about a 0.9 shrink factor in
the process, but no one else seemed to notice. Ludicrous and somehow quite
appropriate for a politician.

On Wed, 24 Feb 2010 09:05:40 -0500, Joseph Gwinn
wrote:

I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from the
noodle factory, partly as an experiment, and ultimately to give to my 9 year old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). The random error of the 47257 seems to be
about 0.002", largely due to head looseness. I tightened the head gib, and the
error dropped to about 0.001", which is what HF claims. I don't know how well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as this
takes some force. The caliper came in a plastic case, and shipping damage was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a coating of
blackish grease, which easily wiped off. But still there was too much drag and
slip-stick. It turns out that the bar was precision ground but not polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly
filing away at the gib, which is brass. Not good, so I polished the grind marks
by hand with crocus cloth. This helped immensely. I suppose that crocus cloth
wrapped around a metal sanding block would do an even better flat polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery, but it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

Yikes, $30? Wait for a sale, mon! They're often on sale for about
$15 and recently for $9.99.

I have several of them because I regard them as consumable, disposable
and handy. I have a Mitutoyo at the lathe but I don't think it's any
more accurate than the HF versions I have distributed around my shop,
cars and various remote progeny who dream up "daddy do" projects now
and then. Battery life is better in the Mitutoyo but the price
difference would cover a couple of decades worth of batteries.

A digital caliper is no substitute for a micrometer, but it beats the
hell out of a tape measure or a guess and often suffices in my shop.

In article ,
Don Foreman wrote:

On Wed, 24 Feb 2010 09:05:40 -0500, Joseph Gwinn
wrote:

I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from
the
noodle factory, partly as an experiment, and ultimately to give to my 9 year
old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). The random error of the 47257 seems to be
about 0.002", largely due to head looseness. I tightened the head gib, and
the
error dropped to about 0.001", which is what HF claims. I don't know how
well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as this
takes some force. The caliper came in a plastic case, and shipping damage
was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a coating
of
blackish grease, which easily wiped off. But still there was too much drag
and
slip-stick. It turns out that the bar was precision ground but not
polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly

filing away at the gib, which is brass. Not good, so I polished the grind
marks
by hand with crocus cloth. This helped immensely. I suppose that crocus
cloth
wrapped around a metal sanding block would do an even better flat polishing
job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery, but
it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

Yikes, $30? Wait for a sale, mon! They're often on sale for about
$15 and recently for $9.99.

I'll keep an eye out. All the better for the nephew. But I wasn't going to
wait, and I was already ordering some stuff.


I have several of them because I regard them as consumable, disposable
and handy. I have a Mitutoyo at the lathe but I don't think it's any
more accurate than the HF versions I have distributed around my shop,
cars and various remote progeny who dream up "daddy do" projects now
and then. Battery life is better in the Mitutoyo but the price
difference would cover a couple of decades worth of batteries.

Yes.


A digital caliper is no substitute for a micrometer, but it beats the
hell out of a tape measure or a guess and often suffices in my shop.

Also yes. Even if I have to polish the bar myself to get smooth action. I may
use 600 or 1200 grit wet dry paper wrapped around a piece of HSS tool bit bar as
a sanding block to polish the bar edges. The tool bit bar is ground quite
accurately flat, and is a handy size.


Joe Gwinn

Don Foreman wrote:

On Wed, 24 Feb 2010 09:05:40 -0500, Joseph Gwinn
wrote:

I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from the
noodle factory, partly as an experiment, and ultimately to give to my 9 year old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). The random error of the 47257 seems to be
about 0.002", largely due to head looseness. I tightened the head gib, and the
error dropped to about 0.001", which is what HF claims. I don't know how well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as this
takes some force. The caliper came in a plastic case, and shipping damage was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a coating of
blackish grease, which easily wiped off. But still there was too much drag and
slip-stick. It turns out that the bar was precision ground but not polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly
filing away at the gib, which is brass. Not good, so I polished the grind marks
by hand with crocus cloth. This helped immensely. I suppose that crocus cloth
wrapped around a metal sanding block would do an even better flat polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery, but it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

Yikes, $30? Wait for a sale, mon! They're often on sale for about
$15 and recently for $9.99.

I have several of them because I regard them as consumable, disposable
and handy. I have a Mitutoyo at the lathe but I don't think it's any
more accurate than the HF versions I have distributed around my shop,
cars and various remote progeny who dream up "daddy do" projects now
and then. Battery life is better in the Mitutoyo but the price
difference would cover a couple of decades worth of batteries.

A digital caliper is no substitute for a micrometer, but it beats the
hell out of a tape measure or a guess and often suffices in my shop.

I've also had great luck with them and have a number of the 6" version
and one of the 12" version. I'm not doing aerospace stuff so I don't
need that many decimal places of accuracy anyway.

I don't have a problem with battery life, I just remove the batteries
before I leave the shop, and only reinstall them when I need to use the
caliper.

On Feb 24, 11:47*pm, Don Foreman
wrote:
On Wed, 24 Feb 2010 09:05:40 -0500, Joseph Gwinn





wrote:
I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from the
noodle factory, partly as an experiment, and ultimately to give to my 9 year old
nephew.

It is functional, albeit more crudely made and less accurate than a Mitutoyo
(which costs four times as much). *The random error of the 47257 seems to be
about 0.002", largely due to head looseness. *I tightened the head gib, and the
error dropped to about 0.001", which is what HF claims. *I don't know how well
the gib adjustment will hold - the two adjustment screws seemed a bit loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. *No idea how it was bent, as this
takes some force. *The caliper came in a plastic case, and shipping damage was
not apparent.

The head slid reluctantly on the bar. *This appeared to be due to a coating of
blackish grease, which easily wiped off. *But still there was too much drag and
slip-stick. *It turns out that the bar was precision ground but not polished,
leaving grind marks perpendicular to the bar, so the grind marks were slowly *
filing away at the gib, which is brass. *Not good, so I polished the grind marks
by hand with crocus cloth. *This helped immensely. *I suppose that crocus cloth
wrapped around a metal sanding block would do an even better flat polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with pure
lanolin (used for instance to lubricate brass musical instruments). *Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery, but it
came with two alkaline cells. *Another corner cut.

I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

Yikes, $30? *Wait for a sale, mon! *They're often on sale for about
$15 and recently for $9.99.

I have several of them because I regard them as consumable, disposable
and handy. *I have a Mitutoyo at the lathe but I don't think it's any
more accurate than the HF versions I have distributed around my shop,
cars and various remote progeny who dream up "daddy do" projects now
and then. *Battery life is better in the Mitutoyo *but the price
difference would cover a couple of decades worth of batteries.

A digital caliper is no substitute for a micrometer, but it beats the
hell out of a tape measure or a guess and often suffices in my shop.- Hide quoted text -

- Show quoted text -

HF has several grades of calipers, I've been getting the "improved"
models that have larger LCD displays lately. In-store price is $10-15
for the 4"-6" models. At least one model turns itself off until the
slider is moved, then it picks up where it left off, no re-zeroing.
Also remembers inch or metric. The really nifty one also does
fractional inch. I use them in various tool kits for beaters, like
with the wood planer, for closer-tolerance work I've got name-brand
mikes and calipers. As you say, they beat using scales most times. I
usually have a 4" in the pocket when hitting the hardware store. If
you hit the internet, you can usually pick up the alkaline button
cells for $4-$5/50. I go through a lot of them with various laser
bore sighters and LED lights.

Stan

"Joseph Gwinn" wrote in message
...
I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from
the
noodle factory, partly as an experiment, and ultimately to give to my 9
year old
nephew.

It is functional, albeit more crudely made and less accurate than a
Mitutoyo
(which costs four times as much). The random error of the 47257 seems to
be
about 0.002", largely due to head looseness. I tightened the head gib,
and the
error dropped to about 0.001", which is what HF claims. I don't know how
well
the gib adjustment will hold - the two adjustment screws seemed a bit
loose.

The clamp thumbscrew (that locks the head to the bar) was bent, so I
straightened it with an adjustable wrench. No idea how it was bent, as
this
takes some force. The caliper came in a plastic case, and shipping damage
was
not apparent.

The head slid reluctantly on the bar. This appeared to be due to a
coating of
blackish grease, which easily wiped off. But still there was too much
drag and
slip-stick. It turns out that the bar was precision ground but not
polished,
leaving grind marks perpendicular to the bar, so the grind marks were
slowly
filing away at the gib, which is brass. Not good, so I polished the grind
marks
by hand with crocus cloth. This helped immensely. I suppose that crocus
cloth
wrapped around a metal sanding block would do an even better flat
polishing job.

After cleaning all the nasty grease away, I lubricated the caliper with
pure
lanolin (used for instance to lubricate brass musical instruments).
Pretty
smooth now.

The manual says that the caliper requires a SR44 (silver oxide) battery,
but it
came with two alkaline cells. Another corner cut.


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

I have the 4" and the 6" from HF. They work just fine in a work environment.
Several of the guys have them now. Change the battery about once a year.
Seem to be just as accurate as anything else, when measuring the same part
with different brands. I prefer the 4" HF to my 8" Mitutoyo. It get into
tight areas better. Yes there is a difference in the feel when you slide
them open and closed, but they measure the same. When my 12 dial gives up I
will get the 12" HF to replace it with. Since I don't use the 12" much I may
never need to replace it. I have worn out 3 of the 8" digital Mitutoyos over
the years and tossed them. Except for one I use for auto repair.

Richard W.

In article ,
"Richard W." wrote:

"Joseph Gwinn" wrote in message
...
I just got a $30 Harbor Freight (item 47257) six inch digital caliper, from
the noodle factory, partly as an experiment, and ultimately to give to my 9
year old nephew.

It is functional, albeit more crudely made and less accurate than a
Mitutoyo (which costs four times as much). The random error of the 47257 seems to
be about 0.002", largely due to head looseness. I tightened the head gib, ...
[snip]


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

I have the 4" and the 6" from HF. They work just fine in a work environment.
Several of the guys have them now. Change the battery about once a year.
Seem to be just as accurate as anything else, when measuring the same part
with different brands. I prefer the 4" HF to my 8" Mitutoyo. It get into
tight areas better. Yes there is a difference in the feel when you slide
them open and closed, but they measure the same.

I am using the HF 6" the test in my shop. The 4" may be a good idea.

But I think it's worthwhile to hand-polish the bar to make the sliding action
smoother.


When my 12 dial gives up I
will get the 12" HF to replace it with. Since I don't use the 12" much I may
never need to replace it.

I use the DRO on my mill for long items.


I have worn out 3 of the 8" digital Mitutoyos over
the years and tossed them. Except for one I use for auto repair.

When a digital caliper wears out, what exactly goes bad?

Joe Gwinn

"Joseph Gwinn" wrote in message
...
In article ,
"Richard W." wrote:

"Joseph Gwinn" wrote in message
...
I just got a $30 Harbor Freight (item 47257) six inch digital caliper,
from
the noodle factory, partly as an experiment, and ultimately to give to
my 9
year old nephew.

It is functional, albeit more crudely made and less accurate than a
Mitutoyo (which costs four times as much). The random error of the
47257 seems to
be about 0.002", largely due to head looseness. I tightened the head
gib, ...
[snip]


I will use this caliper for a while in the shop and see how it goes.

Joe Gwinn

I have the 4" and the 6" from HF. They work just fine in a work
environment.
Several of the guys have them now. Change the battery about once a year.
Seem to be just as accurate as anything else, when measuring the same
part
with different brands. I prefer the 4" HF to my 8" Mitutoyo. It get into
tight areas better. Yes there is a difference in the feel when you slide
them open and closed, but they measure the same.

I am using the HF 6" the test in my shop. The 4" may be a good idea.

But I think it's worthwhile to hand-polish the bar to make the sliding
action
smoother.


When my 12 dial gives up I
will get the 12" HF to replace it with. Since I don't use the 12" much I
may
never need to replace it.

I use the DRO on my mill for long items.


I have worn out 3 of the 8" digital Mitutoyos over
the years and tossed them. Except for one I use for auto repair.

When a digital caliper wears out, what exactly goes bad?

Joe Gwinn

The measuring surface wears out. So you get different readings at the
bottom, center and top of the jaws. Adjusting the gib screws won't make up
for wear on the jaw faces.

Richard W.

"Richard W." wrote:

The measuring surface wears out. So you get different readings at the
bottom, center and top of the jaws. Adjusting the gib screws won't make up
for wear on the jaw faces.


I'd drop coin for a Mitutoyo 6" digital with carbide inserted OD jaws in an instant. Makes
for a nice scriber for laying out a features on a detail. Uncle has an old Mitutoyo dial
caliper with the carbide jaws.

Consider it a poor mans height gage.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller