parallels

[RobinHood]

Getting back to parallels…

My 1/4” ones showed up yesterday. UPS Standard shipping from Eastvale, CA (yes, it was free shipping & no UPS “dinger fees/extra charges” - not sure how they do that…)

After cleaning them (and a light stoning of the sharp edges), decided to break out some measuring tools to see how “good” they are.

These are the tools I used. One is a Swiss Made Etalon 0-1” tenths mic and the other is a Made in England Moore & Wright 1-2” tenths mic. The 1” gage block is an 0 grade Mitutoyo (for reference). I also used a 50 millionths Starrett Dial Master held in a Compaq (Geneve) instrument stand.

And here are the results. All measurements are in 1/10000 inches except for the thickness (it starts with the period and is in thousands of an inch and is the approximate average thickness). The three numbers across the top are deviations from the nominal height of the parallel using a tenths mic to measure in three spots. The boxed number is the “swept” value across 6” using the Dial Master on the Mitutoyo Grade A surface plate.

There is one “outlier” in the set: it is the top of the 7/8” ones. It has a very, very light bow in it. This was confirmed by a “hinge” test on the surface plate and the fact that the center is 2 tenths higher than the ends even though measuring the height shows no deviation along its 6” length (other than that it is 2 tenths over nominal of 0.875”.

Both 3/4” ones also have a minuscule bow in them.

So, are they good parallels? I would say so. I think they are within their claimed +/- 0.0002 (4 tenths TIR) tolerance of parallel over 6”.

NOTE: I am NOT sponsored by the vendor / manufacturer to promote them. I paid full price. I did this as “a fun afternoon project” because I was curious myself of how ”good” they are. Now I know.

 

[PeterT]

And here are the results. All measurements are in 1/10000 inches except for the thickness (it starts with the period and is in thousands of an inch and is the approximate average thickness). The three numbers across the top are deviations from the nominal height of the parallel using a tenths mic to measure in three spots. The boxed number is the “swept” value across 6” using the Dial Master on the Mitutoyo Grade A surface plate.

Good testing & nice equipment. I'm not quite sure I follow your nomenclature. Using this example you are saying
- the nominal thickness of 1/4" = 0.250 varies from 0.253 - 0.252"? (I've never really considered this a critical surface for any particular purpose but I think you are just showing this for completeness?)

- and then the (+2 +2 +2) and (+3, +3, +4) are left/center/right number of tenths relative to... the 7/8 = 0.8750"? (ie. you measured 0.8752 and show the '2'?)
- so I'm inferring the highest runout you would get by arranging them worst way is 4-2=2 tenths high on a supported corner?

- I'm still confused by the box number

 

[RobinHood]

Sorry, wasn’t clear at all with my dimensioning. Should have used a sketch right off the bat…

Please refer to the above.

In the red circle the manufacturer has indicated the size of the parallel. In this case a 1/4 x 1-5/8 x 6.

The critical dimension is what I call the height, in this case 1-5/8”. The deviation from this was measured in three spots (blue arrows) and indicated in tenths from the nominal.

Also in the red circle is what I call the nominal thickness, in this case 1/4”. We don’t usually use a parallel in that direction because it is not precisely ground that way. So the average measurement (taken in about 10 spots on that surface) comes out to the figure in the circle, in this case 0.2515” thick. I did not bother to show how much it varied because we don’t use it that way. More to show that this is not a critical surface and it can not be trusted. I could “map” it, but it would only show that it can’t be trusted for precision work.

Since measuring the height of the parallel in different spots does not give an indication if the top and bottom surfaces are flat, I checked them with the Dial Master on the surface plate by “sweeping” side to side. The result of this test is the number in the square box. In the example case 0 tenths deviation along the 6” length. This means that both the top and bottom surfaces (which are the critical ones) are not only parallel but also flat.

(The 3/4” and one of the 7/8” parallels in my set with the slight bow in them are good examples of why just measuring a parallel with a mic is not good enough. You can see that the distance between the top and bottom surface is very close (( only about 1/10000” deviation over 6” as measured in three spots)) and yet the surfaces are not flat as indicated by the “sweep” test number of 1.5, 1.5, 2.0 tenths).

 

[Susquatch]

Sorry, wasn’t clear at all with my dimensioning. Should have used a sketch right off the bat…

View attachment 25403

Please refer to the above.

In the red circle the manufacturer has indicated the size of the parallel. In this case a 1/4 x 1-5/8 x 6.

The critical dimension is what I call the height, in this case 1-5/8”. The deviation from this was measured in three spots (blue arrows) and indicated in tenths from the nominal.

Also in the red circle is what I call the nominal thickness, in this case 1/4”. We don’t usually use a parallel in that direction because it is not precisely ground that way. So the average measurement (taken in about 10 spots on that surface) comes out to the figure in the circle, in this case 0.2515” thick. I did not bother to show how much it varied because we don’t use it that way. More to show that this is not a critical surface and it can not be trusted. I could “map” it, but it would only show that it can’t be trusted for precision work.

Since measuring the height of the parallel in different spots does not give an indication if the top and bottom surfaces are flat, I checked them with the Dial Master on the surface plate by “sweeping” side to side. The result of this test is the number in the square box. In the example case 0 tenths deviation along the 6” length. This means that both the top and bottom surfaces (which are the critical ones) are not only parallel but also flat.

(The 3/4” and one of the 7/8” parallels in my set with the slight bow in them are good examples of why just measuring a parallel with a mic is not good enough. You can see that the distance between the top and bottom surface is very close (( only about 1/10000” deviation over 6” as measured in three spots)) and yet the surfaces are not flat as indicated by the “sweep” test number of 1.5, 1.5, 2.0 tenths).

Good stuff @RobinHood . I VERY much appreciate what you did. That was a lot of work that was very meticulous and very well done. I think we all learned something about our parallels.

Can you tell us a bit about that dial master of yours?

 

[RobinHood]

The Dial Master No. 25-106 is an old version of their new No. 25-109J dial indicator.

25-109J Dial Indicator

The Starrett 25 Series Dial Indicator has a shockless, hardened steel gear train and jewel bearings, except where noted. It is furnished with a lug-on-center back. Antimagnetic mechanism is optional for all models. Special non-shock mechanism is available for all models except 25-109, 25-209 and...

www.starrett.com

As you can see, the dial only reads -/+ 0.0015, for a total measuring range of 3 thou. It has the standard Starrett mounting lug on the back. It is very sensitive.

It is perfect for comparison measurements of close tolerance parts - like parallels.

 

[Susquatch]

The Dial Master No. 25-106 is an old version of their new No. 25-109J dial indicator.

As you can see, the dial only reads -/+ 0.0015, for a total measuring range of 3 thou. It has the standard Starrett mounting lug on the back. It is very sensitive.

It is perfect for comparison measurements of close tolerance parts - like parallels.

I love it. I didn't even know it existed.

Dumb question: do you know if they make a dial test indicator (needle type) version?

 

[Dabbler]

I have a 1/2" set, and a 1/8" set, but no a 1/4" set - you guys! now I'm tempted!

To add versitility, I have a set of HSS blanks in my parallel set, in pairs: 1/2" 1/4" and 1/8" HSS blands are blanchard ground and are easily within one half thousandth. Sometimes a piece needs just a 'little lift'

 

[Dabbler]

if they make a dial test indicator (needle type) version?

Interrapid makes a .00005 dial test indicator, and used ones are available. I use my one tenths for most things, but a half-tenths has been on my radar.

I do have a Marr half hundredths (5 millionths) indicator for the really picky stuff.

 

[RobinHood]

do you know if they make a dial test indicator (needle type) version?

From their web site it appears that the DTIs only go to tenths, not 50 millionths (half-tenths)

Test Indicators

Test Indicators

www.starrett.com

 

[Susquatch]

Interrapid makes a .00005 dial test indicator, and used ones are available. I use my one tenths for most things, but a half-tenths has been on my radar.

I do have a Marr half hundredths (5 millionths) indicator for the really picky stuff.

I guess I've lived a sheltered life. I've only ever seen tenths. Of course, one can read in between the lines to a third of a tenth or so (with my eyes). But I'd really like half tenths or better yet hundredths but prolly couldn't afford it even if they did make it.

 

[Dabbler]

But I'd really like half tenths or better yet hundredths but prolly couldn't afford it even if they did make it.

You can get Russian 'Marr clones' on ebay from time to time that read in the hundredths or half-hundredths, and they aren't expensive, cause most people don't know how to use them or have the right stand, etc to use them properly. they only read +/- .8 thou

 

[LenVW]

Nice spot during the hot spell we have been having, it's always a few degrees cooler with the on-shore breeze. Nice beach at Bayswater as long as you don't mind the touch of the north Atlantic! Hope you got out off the tourist trail.


Me too! Born & raised here, been around a few corners of the globe including working in bella italia for a while but there's no place like home. Seeing how the other half lives makes you appreciate it even more. New Zeland was pretty nice though....

D

We rented a renovated home on the Cove at Aspotogan. Nice sheltered inlet, about 5 miles across the water from Peggy’s Cove and Bayswater Beach was a mile away.
We were at Deep Cove, NS, in 2015 where we took in alot of Halifax, Lunenburg and the Bay of Fundy. Even climbed to the top of Castle Rock just off the OLD rail trail.

 

[Tecnico]

You know, I didn't know about Castle Rock, I'll have to put that on my to do list.

D

 

[LenVW]

You know, I didn't know about Castle Rock, I'll have to put that on my to do list.

D

It is about a 3 hour hike from the parking lot near East Lake & #103 Hwy. The toughest is the last 100 yards where you have to climb the side of the rock plateau. Your reward is the view of the entire Aspotogan Penninsula.

 

[Susquatch]

It is about a 3 hour hike from the parking lot near East Lake & #103 Hwy. The toughest is the last 100 yards where you have to climb the side of the rock plateau. Your reward is the view of the entire Aspotogan Penninsula.

Bookmarked.

 

[LenVW]

I you need more info @Tecnico.
Just PM me.
We are getting away of the ‘Parallels’.

 

[Susquatch]

I you need more info @Tecnico.
Just PM me.
We are getting away of the ‘Parallels’.

Please don't. I am enjoying the travel tips as much as the parallel discussion.

Perhaps I'm different than other members. I enjoy the journey as much as the subject at hand. It's like a conversation in the shop. We talk about parallels and we talk about other stuff too. And I like that. I'm not fussed about off-topic discussion unless it takes over.

But that's a personal opinion that others may not share.

Ive been to the Maritimes many times. But I'd like to bring my bride and see the whole place in better detail. I don't want to be left out of a PM discussion. Better to start another thread if you feel the need.

 

[Chicken lights]

Please don't. I am enjoying the travel tips as much as the parallel discussion.

Perhaps I'm different than other members. I enjoy the journey as much as the subject at hand. It's like a conversation in the shop. We talk about parallels and we talk about other stuff too. And I like that. I'm not fussed about off-topic discussion unless it takes over.

But that's a personal opinion that others may not share.

Ive been to the Maritimes many times. But I'd like to bring my bride and see the whole place in better detail. I don't want to be left out of a PM discussion. Better to start another thread if you feel the need.

If you’re looking for an off the path suggestion, I’d drive up to Happy Valley Goose Bay, carry on to catch the ferry to the Rock, spend a couple days there then the ferry back to main land. Then either follow the shore north in NB up to the Gaspe Bay peninsula, or follow the other shore back to Bay of Fundy

 

[Susquatch]

If you’re looking for an off the path suggestion, I’d drive up to Happy Valley Goose Bay, carry on to catch the ferry to the Rock, spend a couple days there then the ferry back to main land. Then either follow the shore north in NB up to the Gaspe Bay peninsula, or follow the other shore back to Bay of Fundy

I've done those trips myself already. You are right, they are awesome. I want to bring my bride with me next time I go and I'd like to find a few hidden gems off the highway and beaten path for her to enjoy. We both like hiking so that lookout that @LenVW suggested sounds great.

On the Rock, there are a few I could mention too. There is an oceanside research station north of St. John open to the public that has deep ocean water piped into it and pressure controlled tanks so you are glimpsing the ocean bottom as if you were there. South of that is a small tiny self serve self cook restaurant built into the brown rock cliffs overlooking the ocean. Fresh fish in the restaurants of St. John Harbour are a treat. The lobster bisque is to die for. Battery Hill overlooks the ocean in a way few other places do. Once in a while giganormous ice burgs the size of a whole town float by. Point Fierce (not sure that's right) South of St. John is the eastern most place in North America. Sometimes whales breach in the ocean off shore. Beautiful views and a nice walk in some of the cleanest and sweetest air you will ever breathe.

 

[Chicken lights]

I've done those trips myself already. You are right, they are awesome. I want to bring my bride with me next time I go and I'd like to find a few hidden gems off the highway and beaten path for her to enjoy. We both like hiking so that lookout that @LenVW suggested sounds great.

On the Rock, there are a few I could mention too. There is an oceanside research station north of St. John open to the public that has deep ocean water piped into it and pressure controlled tanks so you are glimpsing the ocean bottom as if you were there. South of that is a small tiny self serve self cook restaurant built into the brown rock cliffs overlooking the ocean. Fresh fish in the restaurants of St. John Harbour are a treat. The lobster bisque is to die for. Battery Hill overlooks the ocean in a way few other places do. Once in a while giganormous ice burgs the size of a whole town float by. Point Fierce (not sure that's right) South of St. John is the eastern most place in North America. Sometimes whales breach in the ocean off shore. Beautiful views and a nice walk in some of the cleanest and sweetest air you will ever breathe.

I’ve never been up into the territories

That’s on my to do list