Granite Plate

[PeterT]

After years of dithering I decided to bite the bullet. Its a 12x18x3" Grade B (overall unilateral flatness tolerance: ±0.0001"). Sourced from Sowa in Edmonton procured through DMH in Calgary.
So the journey begins. I have to make a proper protection lid, for now 1/8" hardboard.

Does anyone have some favorite suppliers of bluing goop? I have a small tube somewhere, I'm actually not even sure its the same stuff. I see people have these hard rubber rollers to evenly distribute on the granite, is that like an art supply item maybe?

12"x18" Grade B Black Granite Surface Plate - Inspection Surface Plates

12"x18" Grade B Black Granite Surface Plate - • Brand: STM<br>• Color : Black<br>• Material : Granite<br>• Overall Unilateral Flatness Tol. (Decimal Inch) : ±0.0001<br>• <a href="/INTERSHOP/static/BOS/Sowa-Site/Webshop_CA/Sowa-Webshop_CA/en_US/Catalogue-Pages/F20.pdf">Download catalogue page</a>

www.sowatool.com

 

[PeterT]

I'm going to start a new post on indicator stand, but just related to above, I pulled out my 'scribey block thingy'. It came from KBC long time ago & has seen little use. It does not have a balled end on the rod accessory like @Mcgyver showed us for square setting. The clamp is not a wonderful fit on the vertical post. I would have to modify or remake it to hold an indicator stem assembly. It does have an integrated fine adjustment pivot. The base underside has 2 flats either side of a notch. Don't know how flat it is yet. I have have seen old school indicator bases which have a pocketed recess on the face so the plate contact is kind of a peripheral ring area. It has 2 vertical dowel pins which must be there for a reason, but its evading me.

Anyway, I'm considering making a surface gage assembly dedicated to dial gage holding. Partly as an exercise in making a nice tool & partly because many of the used offerings on Ebay in my range look like they need work & who knows the history. Haven't decided yet. Likely I could pull a favor & get the base ground, or maybe scrape? I like the looks of Doug Ross design for example. So I'll make a new post when the time comes. Meanwhile if you have seen any plans or desirable features, keep them in mind.

Surface Gage - HomemadeTools.net

I built this gage to use as a primary height and square gage, not as a surface gage, I have dedicated surface gages but I wanted to have a dedicated

www.homemadetools.net

 

[DPittman]

It has 2 vertical dowel pins which must be there for a reason, but its evading me.

My Browneand Sharp "scribey block thingy" also has those two pins that I've never understood either. When you figure that out let me know too.
Also my version is clearly marked "Not hardened", is there any good reason (other than cost maybe) one would want the base not hardened? Every picture I see of this model on the interweb seems to be a hardened model.

 

[whydontu]

The pins can be pushed down to use against an edge to scribe a line parallel to the edge.

Hardened or not hardened? The cheaper component is sacrificial. Using a hardened steel surface gauge on a cast iron surface plate risks scratching the surface plate, so gauges are available un-hardened. Better to have wear on a softer $$ surface gauge than on the $$$$ surface plate.

 

[Canadium]

over the past year I've acquired at auctions 2 height gauges, a dial gauge holder, and a surface gauge but still just have a puny 9X12 surface plate. Was seriously considering buying a bigger plate but the want list just seems to have no end! I'm still kicking myself for not taking the pink granite Starrett 18X24 at a local auction about 5 years back. It had no bids and would have almost been free. At the time I was just thinking about wood working and my car seemed too small for the surface plate.

 

[jcdammeyer]

I used mine a lot during the building of my Gingery Lathe. Since then, not so much. Perhaps because I have a DRO on the mill so scribing lines just isn't needed.

For checking flatness and scraping I used the Permatex Blue.

 

[Dan Dubeau]

The pins are for riding along an edge. Handy when using a test indicator in the surface gauge, for making sure assemblies are parallel. I use them like that a lot in fixture building.

 

[DPittman]

I used mine a lot during the building of my Gingery Lathe. Since then, not so much. Perhaps because I have a DRO on the mill so scribing lines just isn't needed.

For checking flatness and scraping I used the Permatex Blue.
View attachment 28034

Hey I've got a blue scribe just like that one on the left. No brand name on mine and pretty basic. I use mine for setting lathe tool height.

 

[Rauce]

The rubber rollers are called brayers and are indeed an art supply item.

I have the permatex brand Prussian blue as well.

 

[PeterT]

The rubber rollers are called brayers and are indeed an art supply item.

aha, perfect, thanks

 

[Dabbler]

After years of dithering I decided to bite the bullet.

congrats!

If you get any surface gauge we can easily scrape it to flat.

Usually your indicator is held in an attachment on a height gauge. I have extra.

 

[Canadium]

The rubber rollers are called brayers and are indeed an art supply item.

I have the permatex brand Prussian blue as well.

Whats your favorite source for the Permatex blue? I was looking for some a couple years back and found a wide range of prices, mostly either ridiculously expensive or out of stock. Ended up getting Dykem from KBC instead.

 

[Dabbler]

I got mine from Fastenal. Refills will have come from the Internet, unfortunately.

 

[thestelster]

Whats your favorite source for the Permatex blue? I was looking for some a couple years back and found a wide range of prices, mostly either ridiculously expensive or out of stock. Ended up getting Dykem from KBC instead.

https://www.amazon.ca/Permatex-80038-Prussian-Blue-75-Tube/dp/B000HBM86Q/ref=asc_df_B000HBM86Q/?tag=googlemobshop-20&linkCode=df0&hvadid=293033552569&hvpos=&hvnetw=g&hvrand=15428435749641052851&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1002306&hvtargid=pla-487116926566&psc=1

 

[Rauce]

Whats your favorite source for the Permatex blue? I was looking for some a couple years back and found a wide range of prices, mostly either ridiculously expensive or out of stock. Ended up getting Dykem from KBC instead.

I’m pretty sure I got it from Amazon just because it was easy. I’ve seen it at auto parts places though. I’d suggest just buying one or two of the little tubes, a little goes a long way and you don’t go through it very quickly.

 

[trlvn]

The clamp is not a wonderful fit on the vertical post. I would have to modify or remake it to hold an indicator stem assembly.

Harold Hall's web site has some ideas for home made indicator accessories:

Dial Test Indicator Accessories, and with other uses 01

Accessories for use with the a Dial Test Indicator, or a Dial Indicator, but with other uses, typically, a machine gaurd holder.

www.homews.co.uk

There is also a Youtube video that gives a short overview of some of the gizmos. For example, the round 'base' in the top-centre of the picture, above, is sized to fit the T-slots of his Myford lathe which makes it useful for tasks like centering stuff in the 4-jaw.

As an aside, after looking at the interchangeable parts that Hall made, it made me realize that the magnetic bases and related arms I've accumulated are a hodgepodge of sizes. Some metric, some imperial and others that aren't a whole number in either measuring system! If I was smart, I'd unload a bunch of them and aim for a set that is 'less diverse'.

Craig
(I could swear there was a sketch with suggested dimensions but I can't seem to locate it.)

 

[Proxule]

The pins are for riding along an edge. Handy when using a test indicator in the surface gauge, for making sure assemblies are parallel. I use them like that a lot in fixture building.

That is assuming the granite plate is ground properly at 90 degrees, I went thorugh this before too.

 

[PeterT]

It looks like Dykem (a manufacturer name) also makes a high spot / Prussian blue in addition to layout blue. Maybe that's the confusion.
Yes the Amazon price is one of those berzerk outliers that seems to come up for some strange reason.
I've also heard a certain brands or formulas of high spot blues are more difficult to remove. I'll have to dig mine out & experiment a bit

 

[L98Fiero]

I got mine from Fastenal. Refills will have come from the Internet, unfortunately.

Not sure about your branch but you can't get into my local Fastenal, maybe requires a special pass or something, and they don't do one off sales, you need an account, frankly, it's easier to set up an account at McMaster-Carr and get it from there.

 

[jcdammeyer]

Since my tube was almost empty I took the plunge and ordered another. Should be here tomorrow. Use this search string at Amazon.ca

Permatex 80038 Prussian Blue.75 fl oz Tube ​

Amazon.ca