Dial test indicators

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Harold_V
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Post by Harold_V » Sat Feb 21, 2009 2:47 pm

Metalman wrote: What would be best in terms of divisions, range, etc. ?
It is difficult to buy one better than the B&S BesTest, which is marked in half thou (.0005") units. For everyday use, they are likely the best indicator on the market, and can be acquired for a reasonable price on ebay.

I recently bought a third one when one of my old ones was in need of a crystal replacement. It was cheaper to buy the indicator than to have the old one serviced.

Now I need to find a source for the crystal. Replacing it shouldn't be much of a chore. In spite of the indicator's age (over 40 years old now), it still works flawlessly.

Harold

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BadDog
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Post by BadDog » Sat Feb 21, 2009 3:24 pm

I've gone a bit nuts on DTIs. Partly because I lucked into the option to cherry pick an inspection lab before it hit auction. Anyway, I had the opportunity to pick up and try a large range of indicators that were in good shape (current cert on most). This included just about all the main stream "good brand name" dial indicators. After fooling with them over the last year or so, these are my layman thoughts.

B&S Best Test: These are my favorite across the board. Rugged, priced right. LOTS of mounting options using standard dovetails. And they basically just work the way my mind thinks they should.

Tessa: I've got a Swiss made Tessa that is my personal favorite. Says "fully jeweled". Style identical to the B&S, but seems to have better "feel", and it's a large face.

Interrapid: Very nice in every way. Probably "nicer" than the Best Test in absolute quality. However, I really don't care for it. The price is usually 3 times the B&S, the operation is "backwards", and it has that pin on the back that makes it harder to mount. The 'backwards" needle operation isn't an issue unless you also use other brands. I have one in 0.0001 and also use other res B&S, so the Interrapid sets largely unused.

Federal Test Master: Nice if they work, and I have examples down to 0.00005 (not a typo) that work very well. But I hear they are temperamental and basically not fixable (are any of them really worth fixing? <shrug>)

Starrett Last Word: I just simply do not like these at all. I have a back plunger like the one shown, and other plunger DIs made by Starrett, and I like them very well. But not the DTIs. I just gave one away today...

Mitutoyo: They make good stuff, generally... But not the DTIs. It's a wash which I like the least. The Starrett has issues, but generally has at least decent "feel" when kept clean enough. The Mitu works more like the B&S plus it uses the dovetail mounts I prefer (and have LOTS of tooling to support), but it feels worse than many "budget brand" Chinese DTIs I've used. I mean it really does feel AND look poorly made. Save your money, get an upgrade at Harbor Freight in the unmarked box...

I also have some others that I won't take time to detail because they are not at all common.

For what it's worth, that's my opinion as a neophyte HSM who has been fortunate enough to actually own/use many types and form an opinion of what suites best. You may or may not agree, but I find I reach for my B&S (or the Tessa) every time...
Russ
Master Floor Sweeper

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Andypullen
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Re: Flea markets

Post by Andypullen » Sat Feb 21, 2009 3:56 pm

Bill Shields wrote:Stocked by USNA?
Nope....There a couple of new ones in the drawer in the toolroom but I was encouraged to bring my own tools in, so I did. That's unusual for a gov't facility, but I guess that makes me more protective of the tools I have. They did buy me a nice new Kennedy roll-around to put the other toolboxes on. I have it stuffed into a corner next to my bench and a cabinet.

Andy Pullen
Clausing 10x24, Sheldon 12" shaper, ProtoTrak AGE-2 control cnc on a BP clone, Reed Prentice 14" x 30", Sanford MG 610 surface grinder, Kalamazoo 610 bandsaw, Hardinge HSL speed lathe, Hardinge HC chucker, Kearney and Trecker #2K plain horizontal mill.

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Metalman
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Post by Metalman » Sat Feb 28, 2009 8:22 am

I used the indicator to square the mill head and it worked fine, close enough for now. Is it perfect? Likely not but no movement on the .001 graduated dial the difference is probably under .0005". I attached a photo of my Rube Goldberg rig using one of the clamps from the old Starrett kit. The disc is a discarded brake rotor turned clean on a brake lathe. I checked the rotor with the mic and it's within about .0002". I suppose a grinding operation would be better for the disc but right now the whole set is better than what I had before (nothing) :!: .
Attachments
Mvc-353x.jpg
Tram rig
Ernie F.

BMyers
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Post by BMyers » Sat Feb 28, 2009 9:47 am

not to highjack the post, but I am looking for a 196 indicator. If someone has one that dont want drop me a PM.

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Lew Hartswick
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Post by Lew Hartswick » Sat Feb 28, 2009 10:19 am

Metalman wrote:II attached a photo of my Rube Goldberg rig using one of the clamps from the old Starrett kit. The disc is a discarded brake rotor .
I recently was given a brake rotor about like that one but has an even bigger
"lump" in the middle. Any suggestions as how to remove the hump?
Also it could use truing up I'm sure. Don't think I can set it up on the lathes
at school. Don't know anyone with a brake lathe. Do have a surface grinder
available but will that work if the rotor has to be moved to get the full dia.?
It's from a Ford 250 and I think may be some heavy duty option.
...lew...

abarton
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Post by abarton » Sat Feb 28, 2009 10:43 am

I bought a new disc rotor from my local auto supply. When I got it home I found that it was axially symmetric, but the center was significantly thicker (I forget how much) than the edges.
Alexander Barton

Harold_V
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Post by Harold_V » Sat Feb 28, 2009 3:16 pm

My personal opinion is that you should not use any device between the indicator and table.

Here's why.

Unless your table is flawless, with no miniscule dings, when you use an object with large surface area, it orients to the error in the table, not to the true table condition. All your efforts go towards erroneous readings.

Unless the table of your mill is free of dings (they rarely are), you are far better served to use the table surface.

If you insist on using a device of any description, you should form the habit of using a single cut file on the table before using the device. Lay the file on the table surface and draw it along with the palms of your hands. A file that is somewhat used, but not completely dull, will take nothing but the highs off the table, leaving the original surface untouched. It is a good way to keep the table in tune, even if you don't use a device for squaring the head.

Harold

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J Tiers
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Post by J Tiers » Sat Feb 28, 2009 5:53 pm

In fact, if you REALLY want to just remove the dings, take an old single-cut file, and break or grind off a chunk of a handy size.

Grind all the edges so they are rounded, leaving the two faces alone.

Then take the file to the sharpening stone, and rub both faces on the sharpening stone until you can see that all the teeth have a small flat on them.

Now, that piece of file will cut off anything that sticks up, but won't cut a surface AT ALL.

When you run it over the surface, you will feel it cut the raised areas. After a while they will be cut down, and you will feel the piece start to glide freely. That means you are done.

A piece of file like that is known as a "burr file".

CarlD
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Post by CarlD » Sat Feb 28, 2009 9:13 pm

I also don't believe in using anything on the table to sweep/tram the head in. I also use a used 14" lathe file and draw file the surface each time I sweep the head or want it flat.

Draw filing is when you move the file perpendicular to it's length flat on the surface.
It's only ink and paper.

abarton
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Post by abarton » Tue Mar 03, 2009 4:00 pm

Harold_V wrote:Unless your table is flawless, with no miniscule dings, when you use an object with large surface area, it orients to the error in the table, not to the true table condition.
I understand. But when I sweep the DTI over the mill table surface in a 8" diameter arc, I cringe every time the probe tip drops into a T-slot. I don't have any idea how much abuse my little DTI can take, bouncing in and out of the slots.

I tried once to orient the probe on my Indicol so that it was tangent to the arc and maybe easier on the DTI but it reduced my "reach" and took some fiddling to do and limited me to only one direction of travel.

Maybe I just need to learn some patience.
Harold_V wrote:If you insist on using a device of any description, you should form the habit of using a single cut file on the table before using the device.
I recently went over the table surface with a 6" stone. I did find a few small dings and got them smoothed out to where I couldn't feel them through the stone any more. Is that as good as draw filing?
Alexander Barton

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BadDog
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Post by BadDog » Tue Mar 03, 2009 6:26 pm

I usually just angle it somewhere in the neighborhood of 45* or so, but mainly just make sure it doesn't hit the slot perpendicular. As long as it has a bit of lead/ramp to climb up, it will be fine. Also, this is a place where the largest ball tip you have is good. The ball itself provides a ramp, but still better to have it trailing a bit. And finally, you only want to have it displace from zero (rest) by no more than necessary, maybe 5-10 thou (depending on range and tip size to some extent).

Those indicators are pretty tough as long and should not be damaged (even if perpendicular to travel) as you don't push it down so far it gets the probe buried in the slot...
Russ
Master Floor Sweeper

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