Surface plates & hand scraping - should I or shouldn't I?

[Tony Wells]

Well Dave, since we're mentioning substitutes, I would be remiss if I didn't mention that one of my early employers started his shop with a tombstone for a surface plate. They can be polished granite, you know.

I've often wondered if the guys who come cert and lap would accommodate that, or would they tell you to get lost.

 

[Tony Wells]

Jerry, it would have the curvature of the earth;

I've seen people lay our wet or dry paper on top of a surface plate for lapping small parts. Sounds like a good opportunity to get grit all over the plate to me.

 

[Highpower]

What about 1/2"- 5/8" thick float plate glass - suposed to be vey flat. I have no idea if it is, or if it would be suitable for your application.

Just a thought

DaveH

Let's see now...... plate glass -- heavy cast iron part -- my butter fingers....... Ummmmmmm........

Well Dave, since we're mentioning substitutes, I would be remiss if I didn't mention that one of my early employers started his shop with a tombstone for a surface plate. They can be polished granite, you know.

I've often wondered if the guys who come cert and lap would accommodate that, or would they tell you to get lost.

Oh PLEASE guys? I'm just dying to get this thing lapped!

Tony,

I shudder to think what is going thro Willie's head now

DaveH

Other than that breeze through my ears?

If you're talking about scraping small parts then I would buy a small black surface plate from Enco and use their free shipping code because the surface plate would be light enough to ship UPS.

Ed

I'm thinking more like 18 x 24 Ed. Some consider that a "small" plate. Go figure. Still truck shipment territory I'm afraid.

I have no idea but what about machinery grout, just make a mold the size you want and pour it in it drys water level extremely hard and would lap like stone, and the cost is not to bad. Just a though.

Jerry.

There would be a problem with dimensional changes do to temperature and humidity fluctuations I'm afraid. Granite is very stable in that regard which is why they use it.

I've seen people lay our wet or dry paper on top of a surface plate for lapping small parts. Sounds like a good opportunity to get grit all over the plate to me.

At least they didn't use Clover compound, eh?

 

[Tony Wells]

At least they didn't use Clover compound, eh?

Well, I can't say I've never seen it done, and I have jumped out some people for abuse of surface plates. Some people don't know how expensive they can be.

I've always wanted a cast iron lap like the surface plate guys use. They seem to last forever. But then, I'd have to have all the other goodies to check the work, ya know? I do know it's a lot of work. One of our plates had a pretty good dip in in due the the Trimos air float dying, and people bring the part to it rather than floating the Trimos over to it. I had to help the guy lap it that time. It's hard work to get a 0.0032 hole worked out a pink. I moved that Trimos over to a black plate after that, then fixed the air system.

 

[Highpower]

Thanks Dave! It's nice to know I can always count on you to come up with a solution when things get tough.
Alas..... I seem to have stumbled upon "Plan B".

Just as I was ready to throw in the towel and violate the pink, I made a last ditch effort and called a KBC Tools store across the river from me and inquired about what they had to offer in black granite. Struck out naturally - nothing in stock. Then I clenched my teeth and asked about shipping charges, awaiting the dreaded answer. The gentleman on the phone paused for a moment and said "Welllllll..... if you don't mind waiting a few weeks, I can put one on my regular stock order and it will be delivered here to the store. You can drive over and pick it up and you won't have to pay shipping.



Now all I have to do is figure out how to sneak it past SWMBO.

 

[Tony Wells]

If the job is not critical down into the tenths, consider getting a piece cut from a blanchard ground tooling plate. Most steel houses can furnish that, and cheaper than granite, I would think. It has been when I've bought it, and you won't ruin it so easily.

 

[Highpower]

Most steel houses can furnish that,

Tony, you'll have to define "steel house" for me. The only places I'm used to dealing with are Speedy Metals, Metal Express, Metal Supermarkets, and similar on-line. Just the typical "general" suppliers. I don't know of anyone (around here at least) that stocks ground tooling plate.

The import 18 x 24 granite plate (Chinese tombstone?) from KBC is $127. Blanchard ground "tooling" plate even sounds more expensive.
But you can color me clueless in this area.

 

[Tony Wells]

Well, the first one that comes to mind is EMJ (Jorgesen Steel). They are a larger company that services various industries in metal good manufacture. It may be a regional thing, and I don't remember where you are, so I can't give you a local example. However, Onlinemetals claims to carry it. Just Google tooling plate, or blanchard ground plate. It's pretty common.I don't know for sure about price comparison, since I never have thought about using tooling plate for a surface plate or a lapping plate, but it should be worth checking out.

 

[Highpower]

Ok, Google is NOT my friend!

Blanchard ground plate.

Tony,
Another side bar question. Are brayer's thoroughly cleaned after every use, or do you just leave them "inked" up? That's one detail I've never seen discussed before.

p.s.
I'm in the Gateway to the West. Or emergency exit to the East, depending on how you want to look at it.

 

[Tony Wells]

Ok, Google is NOT my friend!

Blanchard ground plate.

Tony,
Another side bar question. Are brayer's thoroughly cleaned after every use, or do you just leave them "inked" up? That's one detail I've never seen discussed before.

p.s.
I'm in the Gateway to the West. Or emergency exit to the East, depending on how you want to look at it.

Brayers should be kept clean. That said, during a session, it's not imperative that they be completely free of all ink or dye, but afterwards, they should be cleaned thoroughly. Old dye or ink can interfere with smooth application, so you want to start a job with a fresh, smooth brayer surface.