# Lapping plates



## Hukshawn (Jan 29, 2018)

I am about 3/4 through the lapping plates videos Tom Lipton did. It seems inexpensive and easy to do in any shop. Just takes time. I have a few different lapping and polishing compounds already from various wood working jobs finishing lacquer finishes. I do not believe the aggregate is all that different? 
In any event, I'm thinking about trying this. 
He had ductile iron for most of the video, but at the beginning he had aluminum plates laid out too. Aluminum seems awfully soft?

I've had an idea. To me, lapping plates seems like a poor man's way to surface grind. Lapping and measuring then lapping some more? I suppose I should get a good surface guage, one with that bumping nose on the front? I suppose that could be a project too. 
But, to do things like making 123 blocks and lapping them square off the mill, or, touching up my parralells? Or the vise jaws in currently making. It would allow me to harden them then true them up. I have my eye on a nice bench top surface grinder, but it's very unrealistic I'll come up with the cash. So, a man's gotta look in other directions. 

Thoughts? Opinions?


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## Ulma Doctor (Jan 29, 2018)

using a soft substrate like aluminum will allow the abrasive to embed into the surface of the lap
abrasive embeds in Cast iron too, but not as readily 
you can use lapping plates in lieu of a surface grinder, but time is a factor for large projects
a Dial indicator or Dial Test Indicator would be nice to determine square or parallelism and then to measure your progress


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## Hukshawn (Jan 29, 2018)

Most of the stuff I make I small. And my time is just my time. If it doesn't get done it gets done another night. 
The idea has me inspired.


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## jrkorman (Jan 30, 2018)

Take a look at Tom's latest video. He's using a copper lap and he gets the part flat pretty damn fast! Oh, and that was* after* the part had been ground!


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## Hukshawn (Jan 30, 2018)

I did see that one! It was quick! But I have to assume that chunk of copper was considerably more expensive than the iron and certainly more than the aluminum. 

Any one think of some other ways to cut the slots in the plate? I have many wood saws of sorts, but all the blades would be too thick, and not a fan of the skill saw method (which the blade is quite thin) and I don't have a band saw. 
I don't remember what the width of the groves were. I have a 1mm slitting saw I could rig up some how?


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## Redmech (Jan 30, 2018)

I’m going to watch this thread. I have some interest in making a set


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## Redmech (Jan 30, 2018)

For cutting the slots could you use a small end mill, in a mill. Don’t know if you have a mill though.


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## C-Bag (Jan 30, 2018)

Tom Lipton's 3plate method vid was very inspiring and I got hooked into that too as I had a couple of projects I wanted to do. Mainly fixing things like my supposedly bargain surface gage I got off eBay. But there are details that take deeper understanding. You need a good surface plate, a good height gage and very good test indicators to be able to see what you have accomplished. Or in the case of Tom that optical flat setup.

Stuff off the lathe(the plates) or mill take a lot more than a couple of minutes. He spent a lot of time setting up the plates and if you buy through McMaster Carr it's about $100 with shipping, maybe more. I found a 10" old cast iron lapping plate for $100 delivered off eBay and it's perfect as I can measure across. 


Hukshawn said:


> I am about 3/4 through the lapping plates videos Tom Lipton did. It seems inexpensive and easy to do in any shop. Just takes time. I have a few different lapping and polishing compounds already from various wood working jobs finishing lacquer finishes. I do not believe the aggregate is all that different?
> In any event, I'm thinking about trying this.
> He had ductile iron for most of the video, but at the beginning he had aluminum plates laid out too. Aluminum seems awfully soft?
> 
> ...



The aluminum was what he glued the penny's to make a poor mans copper flat. I didn't see him using it again but he has so many vids I skip around. IMHO it's very useful and I did get pulled in and found an old cast iron 10" lapping plate in wonderful condition and used it to do a job I was wanting to do. If your time is no big deal, yeah it can do some nice stuff. But really is a lot more involved when I went to do it. Because I have the one plate I have to clean it thoroughly when I want to go from coarse to fine or I get scratches. You can go the other way, fine to coarse without cleaning, but when would you do that? Cleaning off the lapping compound can be pretty messy too. A tip he showed in another bid which he made it sound like he did all the time was to use timesaver compound by micro surface ( https://www.ws2coating.com/). I've not gotten to it yet, but I guess this somehow dissolves so you only mix up with oil what you need and it goes away as you use it getting finer and finer. They use it for lapping in rear ends in race cars as the final step after installing the rear end! You just drain the pile after running it a while. Try doing that with usual compound! So I got me a test kit for $35 and am going to try a run again on the old plate.


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## Hukshawn (Jan 30, 2018)

Redmech said:


> I’m going to watch this thread. I have some interest in making a set



Lol. Jeez. I guess I have to do this project now then. 

I thought about a small end mill. But feared I'd just snap a whole boat load of them trying to cut iron. 
Which is what made me think of the slitting saw. I have an 8" rotary table I could mount the plates to. Or even an angle plate would work. Hmmm. I'm more and more intrigued with this. 

However. Its leading to soooo many projects. I'll need to make a surface guage for the surface plate that will accept my DTI. Ill need to make an arbor fory slitting saw I haven't used yet. I'll need to finally build that power feed I've been mulling over, because hand cranking 50 slots super slow will drive a man to drink... And I'll need to finish all the current projects I have on the go right now. 

Maaan, I need a vacation just to find all the time. Haha. 

But I'm seriously considering all this. I emailed metal supplier to get a price on the iron. I'm thinking 6" or 7" plates. Bigger is harder and more time consuming, but a bigger surface will allow me to lap bigger items. Like the 6" vise jaws I'm making. Oh man, that's another project I need to get done. It never ends!!


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## Kernbigo (Jan 30, 2018)

i had a 2 side cast iron surface plate, which i made 1 side into a lapping plate, used a 1/8" ball end mill to mill the slotts, took a lot of time a couple of winters ago.


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## Redmech (Jan 30, 2018)

What did he use to bond the pennies down to the aluminum?


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## Hukshawn (Jan 30, 2018)

I didn't catch it. But I'm sure an epoxy or super glue would suffice. 

What's the advantage of copper for lapping? Anyone?


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## C-Bag (Jan 30, 2018)

Hukshawn said:


> I didn't catch it. But I'm sure an epoxy or super glue would suffice.
> 
> What's the advantage of copper for lapping? Anyone?



It's all about the plate being able to be "charged" which means the compound is able to embed itself in the plate so the part you are lapping isn't really touching the plate, it's riding on the abrasive compound. Cast iron is also good for this and it's why it's also used and why I went this route. Most of the stuff I do like the surface gage, is hard. The thing about the pennies was you had to use older than a certain date because after that they were just copper coated, and in using the penny you wouldn't have to cross cut the surface. 

What I was going to do to cross cut was set up a simple v block piece of wood and like Tom did use a good carbide saw, but on my table saw. Yeah, it would be messy but it would be easier to control than the circular saw he used. I've cut aluminum on my table saw and compound saw, works fine. And now with my HF blade sharpener I can fix if they get dull.


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## brino (Jan 30, 2018)

I never frown at making one yourself, but if you don't have the time, Lee Valley tools has a few lapping plates that are NOT ridiculously expensive.

This one has a 12x4-1/8' surface:
http://www.leevalley.com/en/wood/page.aspx?p=59752&cat=1,43072,59752
This one is 8x3":
http://www.leevalley.com/en/wood/page.aspx?p=69438&cat=1,43072
Either would be big enough for small tools.

They also have some diamond lapping plates and films.
-brino


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## Mitch Alsup (Jan 30, 2018)

Hukshawn said:


> I've had an idea. To me, lapping plates seems like a poor man's way to surface grind.



One machines to 0.001
One surface grinds to 0.000,1
One laps to correct surface grind errors.


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## Hukshawn (Jan 30, 2018)

I AM interested in making the plates myself. Food learning experience. But I have been trying to find a place to purchase the grits. Perfect.


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## ThunderDog (Jan 30, 2018)

> However. Its leading to soooo many projects.


Hukshawn, this is my life now.  

Machining, metrology, etc.,  it's the ULTIMATE rabbit hole.


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## Hukshawn (Jan 30, 2018)

Yeah well... I picked a terrible hobby to have while working two jobs regularly, a 2 year old at home, and a wife who works sporadic shifts.


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## Redmech (Jan 30, 2018)

Watched Tom’s video. Making fllat lapping 4 

He used Loctite 380
And pennies that are 1981 or older, or of course copper washers. 

What would the advantage of copper be over using straight aluminum?  Both are soft materials. I know the copper sort of becomes loaded with what ever grit you put into it versus cast iron you can clean and go to a different roughness/diamond dust, or at least that’s the way I understood it.


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## C-Bag (Jan 30, 2018)

Redmech said:


> Watched Tom’s video. Making fllat lapping 4
> 
> He used Loctite 380
> And pennies that are 1981 or older, or of course copper washers.
> ...



If I was like Tom and had several lapping plates and could devote a plate to different compounds I think more about copper. And maybe if I really get into this I can explore that. I don't remember the rational, but AL doesn't seem to be used. There could be a lot of what I call historical engineering(just the way we've always done it). I don't have as much time as I'd like to devote to this circular rabbit hole of metrology>grinding>lapping>metrology and the other, machine scraping. I'm doing it in steps with projects that need to get done like repair and try not to let me OCD get the best of me.


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## Redmech (Jan 30, 2018)

http://www.southbaytech.com/appnotes/54 Lapping & Polishing Basics.pdf

Some good info I found on this subject


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## C-Bag (Jan 30, 2018)

brino said:


> I never frown at making one yourself, but if you don't have the time, Lee Valley tools has a few lapping plates that are NOT ridiculously expensive.
> 
> This one has a 12x4-1/8' surface:
> http://www.leevalley.com/en/wood/page.aspx?p=59752&cat=1,43072,59752
> ...



Those are kinda cool brino, but after watching Oxtools vid it drove me to find a round plate. A square or rectangular plate to me is harder to work as the idea as far as I see is harder to work over the edge in order to really evenly work the whole plate. It's the only way to keep the plate from getting worn in spots and going out of true. Whoever had my plate before must not have used much or really knew what they were doing as its within .0002 in all directions. That was one of my virtual vulture finds as most of the plates I saw were waaaay too much.


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## Ulma Doctor (Jan 30, 2018)

Hukshawn said:


> I AM interested in making the plates myself. Food learning experience. But I have been trying to find a place to purchase the grits. Perfect.


Hey Shawn,
ebay has everything you need  (i'm not sure if there is a Canadian equivalent to Ebay )
https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=lapping+paste&_sop=15


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