Mechanical Metric Micrometer

Hi Netmaker,

I think this would work:

http://www.wescotools.com/p-8418-fowler-72-224-009-digit-counter-metric-micrometer-with-insulated-frames-0-25mm.aspx

Mike

Thank you.

That looks just like what I am after.

nm

I actually owned a Mitutoyo like that back in the 80'z.

Just out uv curiosity, why don't you want to use a caliper and why not electronic?

To answer both questions:

This particular customer has used a micrometer to set twine standards in their spec sheet .

Twine and finished webbing ( netting) are NEVER measured with a caliper or a micrometer at my shop.

Nor are they ever measured in diameter by the top companies that produce twine and finished netting ( North Europe, Japan/ Asia and West Europe).

They are ALWAYS measured in weight ( denier) and number of plies ( how many fibers per twist or strand). Diameters are ONLY listed as approximate measurements just for reference. I ONLY use this mm /dia. measurement to explain twine and surface area of finished net, to fisheries scientists who DO NOT have a working knowledge of net design.

Using diameter to spec out a netting job is the same as using a lumber yard crayon and a dressmaker's tape to cut steel in a machine shop. It can be done but there will be an obscene spread in accuracy.

They refused my request to use the Denier/Ply system hence, I am looking for the same type of micrometer THEY used to avoid any further discussion.

Thank you for the comments.

Soundz like you made the perfect choice.

See reply # 10.

Thank you for the comments though.

"Measuring range 15.00 mm to 25.00 mm

I will be measuring twine and rope from .80 mm to 15.00 mm."

What's wrong here?↑

And, I'd use a dial indicator with a 25mm flat disk for an anvil, to achieve the same pressure each time, instead of relying on human thumb/finger pressure with either a mic or calipers.

Or, a string to measure the circumference of the twine/rope and a ruler to measure the string.

But, what do I know?

Measuring range 15.00 mm to 25.00 mm

I will be measuring twine and rope from .80 mm to 15.00 mm."

What's wrong here?

Typ-O

Should read :

.....From 0 to either 15mm or 25.00 mm

Thank you for pointing the error.

Since rope is measured by o.d., like a nut across corners rather than across flats, a contact surface wide enough to span a full twist of the twine is ideal. Lyn's 25-mm (1") anvil is just right for typical net twine.

(In some senses, the customer is not always right, but nonetheless you might have to jump through a few hoops.)

Agreed about the customer not being right. My situation is that in some of this work the person writing specs is NOT qualified. However, if he has enough letters behind his name he can convince his colleagues that he is.

By-the-way, I am basically working with something in the 8mm range. on this project. I'd say, 75% of my work is in .800mm ,380/15 through 1.7mm ,380/21....with a few in the 380/60 .

The micron netting for plankton, krill and egg collection is most always in the 350-750 micron range and that material ( Pecap, Nitex and Moji net) is extremely well sized and accurate.

You would be amazed at how many differences there are in twine and rope that are supposed to be a specific size..........and each manufacturer insists they have the correct measurement!

This is concerning just a (almost) standard 3 strand twisted twine. When we get into braided twine, 8 and 16 Carrier, it really gets wild.............

I suppose the micron netting would be monofilament (?), so the o.d. measurement would be easy and unambiguous (if the fiber is consistent).

I forget what number of 3-strand black twine we used for Alaska king crab pots, but we never measured its diameter, which was about 3/32" to 1/8".

It might be that your customer is using the twine thickness and mesh size to compute the % open area of the mesh, which would give some indication of the net's drag until it starts to fill up. Then all the numbers would change.

Nah.....I don't think he has clue about twine surface or drag. I'll get it rounded out by weeks end.

You all probably used something in a 380/48 to maybe a 380/60, HDPE .

Anyway.....I had a customer up there this Summer in the Chukchi Sea...sampling Artic Cod juvies. That's further North than Santa Claus. Ha ha.

15mm net twine? Is this for Captain Ahab? (Sorry, couldn't resist.)

...ha ha........ that large would be used in lift nets for submersibles, but NOT for this job.

It should have read:

.....from 0 to either 15mm or 25mm.

netting for this one should fall around 8mm or 380d/264p depending on how we settle the thumb pressure thing.......Fred and Barney net making... ha ha !

Try looking in Ebay. There's hundreds of them there!

How about 'Go, No-go' gauge?

I have never seen a Go- No Go device.

What is it?

They are fixed gap calipers with upper and lower limits. I'm unable to search successfully one of this kind. The one I found was very similar but doesn't have limits. I'll look for an exact one and let you know. I still feel this should work for your requirement and is cost effective as well.

I have seen this before but not in increments as small as we would use ( mostly .800mm to 6mm for twine and 8mm througth 25mm. for ropes.

Anyway, now I know what it is called.

Nandri.

No offence to those above, but a micrometer is not going to work on laid rope typically with odd strands, like 7 or 19 etcetera.

And second decimal metric is extraordinarily accurate = 0.0004". 4 tenths of a thou for rope?

If you want to get that accurate on something 'spirally', what you need is a comparator set up.

Similar to this, but with a large foot on the indicator and same size bolster beneath.

I should add, personally I'd use one of these;

link

'angled along the rope' so to cover a number of spirals.

Actually, he wrote

"accurate to 00.99 mm ( 2 spaces after the decimal ) "

which woud be good accuracy for a C-clamp with linez scribed in the screw.

(sorry! az a machinist, I coudnt rezist the traditional razzing uv the new kid in the shop!)

....razzing the new kid in the shop, eh?

Well, when I'm up there in Illinois this Spring trying to show your fishery folks how to remove, en masse, those Asian Carp..........I'll make sure to leave at least one healthy breeding pair!

HA ha.. thank you for the input. My machinist friend down here is always talking about 1000th of an inch measurements. It drives him crazy when I say anything close to a cm ( in linear measurement) is good -to-go.

I woud get a healthy breeding pair, develop a super genetic mutant Asian carp, breed a thousand or so, attach lazerz to their frikkin headz and hold the Great Lakes ransom for 1 MILLION DOLLARZ!

I have never seen a Go- No Go device.

What is it?

In this case it would be a slotted measurement tool with one slot gap being the minimum diameter and another slot being the maximum diameter. You would place it over the object and rotate to evaluate the fit.

Ron