Learning to scrape - with help from Richard King

[p3bhambama]

Did a couple rounds this afternoon. Pretty good coverage everywhere but I think I can get it better. I won a few cast iron angle plates at an auction so will be starting those soon. I also won a Taft-Pierce squareness comparator so will hopefully be using that along with a cylinder square to learn to get them perfectly 90

 

[Bakafish]

I also won a Taft-Pierce squareness comparator so will hopefully be using that along with a cylinder square

Nice! Share some pictures?

 

[p3bhambama]

Nice! Share some pictures?

I’ll be happy to! It’s in remarkable shape. Unfortunately my wife is holding it hostage until my birthday on Sunday.
I wish I hadn’t lost out on the matching T-P 5”x12” cylinder square that was in the same auction. Both were from an Army inspection lab and the last inspection sticker said 1969 on them. Neither looked like it had been used at all other than to certify them.

I should’ve just done it but I was low on money so put a $500 max on the one I wanted most and that I figured would be harder to find because I couldn’t watch the auction live. Ended up winning it for $360. The cylinder square only went for $210

 

[Richard King]

You still need to do some dive bomb tech 40 scraping. Look at the rows of opening scrape marks. They ppi looks good, but you can get more ppi if you move faster side to side or do down U - scrape and immediately up lift. In out in out in out, etc so the low rows of opening doesn't happen.

 

[p3bhambama]

You still need to do some dive bomb tech 40 scraping. Look at the rows of opening scrape marks. They ppi looks good, but you can get more ppi if you move faster side to side or do down U - scrape and immediately up lift. In out in out in out, etc so the low rows of opening doesn't happen.

Thanks Richard I will. I haven’t had much time lately and didn’t want to just do one or two passes then stop. On this last round I think I had the Biax running too fast and it caused me to run some scrapes together in violation of the rules lol. Next time I have a good chunk of time (this weekend as I’ve informed the wife my birthday is going to be a shop fun day) I’ll do some dive bombing. Hope you’re doing well.

 

[Richard King]

I'm felling better..my lift arm is still having issues. But I can scrape :-)

 

[avivz]

Did a couple rounds this afternoon. Pretty good coverage everywhere but I think I can get it better. I won a few cast iron angle plates at an auction so will be starting those soon. I also won a Taft-Pierce squareness comparator so will hopefully be using that along with a cylinder square to learn to get them perfectly 90

How many ppi you already have?

 

[p3bhambama]

I'm felling better..my lift arm is still having issues. But I can scrape :-)

Glad to hear that!

 

[p3bhambama]

How many ppi you already have?

I haven’t done a count. Since it’s mostly been for practice I’ve made a conscious effort to not focus on “grading” it in that way and just focus on the process. But as it gets better I will.

 

[p3bhambama]

Starting in on some spotting today. Richard had mentioned rubbing it on a clean portion of the plate to shine the highest spots. I did that but before I did I used some of my dehydrated Charbonnel black luxe as a trace coat. Really makes the high spots stand out.

 

[TGTool]

I'm felling better..my lift arm is still having issues. But I can scrape :-)

Richard isn't back 100% but he's scraping by. Love a guy with a sense of humor.

 

[p3bhambama]

Nice! Share some pictures?

It’s my birthday so the wife finally released the Taft-Pierce. Everything is as pristine as I hoped except that the finish on the outside of the wood box has deteriorated and become sticky. Thankfully woodworking is my wheelhouse so will be easy to restore. Indicator is a tiny bit sticky so will clean that too but otherwise it’s perfect. Also got a really nice Mitutoyo analog electronic indicator box - I love these and have multiple Brown&Sharpe versions but this Mit is even nicer.

 

[Gard]

I am no expert on scraping but have found a couple of things useful not yet mentioned in this post. First the blueing gets applied thinner as the scraping progresses to a flat surface. A thick layer helps me to see where to concentrate the the step scraping and where to avoid. Second is I run a indicator across the surface with the indicator base on the granite. The blued part is set on an intermediate leveling plate which has 3 point contact via adjustable feet. I level it to get the corners close to the same then make a little sketch of how much to remove where. As richard says, like scraping paint.
After it is close this way (several step scrape passes at least) I would flip it over and scrape the bottom parallel to the top so the intermediate plate is no longer needed. The intermediate leveling plate can be crudely made out of almost anything, it is way faster than messing with shims. Once you start scraping machine parts you will be using the indicator a lot to check and adjust alignment between the parts. Connelly suggests a 0.0005" indicator is suitable for most alignment work.

I have learned a lot from Richard King over the last several years including the forums, personal communications and the video he sells. I wish he would also sell the book he provides with his classes. I am sure it would be better to attend a class but I don't see that in the cards for me.

 

[Bakafish]

It’s my birthday so the wife finally released the Taft-Pierce. Everything is as pristine as I hoped except that the finish on the outside of the wood box has deteriorated and become sticky. Thankfully woodworking is my wheelhouse so will be easy to restore. Indicator is a tiny bit sticky so will clean that too but otherwise it’s perfect. Also got a really nice Mitutoyo analog electronic indicator box - I love these and have multiple Brown&Sharpe versions but this Mit is even nicer.

Nice Mitutoyo meter, I hope you can find some probes for it. I just picked up a nice Tesa myself. I was surprised at the 'waffle' design of the base contact surface of that squareness comparator. That looks really nice! I have some compatriots designing their own comparators and I told them to keep it simple, no flexures just a base and a column. You've got a great one there (although I'd be tempted to swap out the indicator for actual use.)

 

[p3bhambama]

Nice Mitutoyo meter, I hope you can find some probes for it. I just picked up a nice Tesa myself. I was surprised at the 'waffle' design of the base contact surface of that squareness comparator. That looks really nice! I have some compatriots designing their own comparators and I told them to keep it simple, no flexures just a base and a column. You've got a great one there (although I'd be tempted to swap out the indicator for actual use.)

Thanks I’m happy with it. The indicator is tenths reading and quite nice I’m inclined to stick with it.

As to the mitutoyo yes it came with one probe (working) and I’ve got 10-12 other ones from another lot when I bought the Brown and sharpe versions. Gonna have to sell some of these bc it’s honestly getting ridiculous lol. This odd Brown and Sharpe “electralign” was in the same auction and I got it super cheap. Apparently it’s for tapers? Honestly no clue. It has dual probes. I thought it might be useful for something

 

[p3bhambama]

Also anyone with ideas on what this is? Clearly shop made and done nicely. The platform moves up and down by screw and a knob connected to some gears underneath.

 

[p3bhambama]

Some progress was made lol. I don’t enjoy spotting as much as the earlier stages of scraping. But it’s still fun. I will continue to refine this plate though I feel like it’s in a good place now. Thanks to the endless patience of Richard King who I believe is holding a class this weekend (I really wanted to go for my birthday weekend but couldn’t swing it) and thanks to all who are contributing to this thread.

Also for those that asked about ppi I threw a few pics of the gage in.

 

[Bakafish]

This odd Brown and Sharpe “electralign” was in the same auction and I got it super cheap. Apparently it’s for tapers? Honestly no clue. It has dual probes.

Dual probes can help eliminate certain kinds of reading errors, although that one does seem to use them in a fixed configuration. The Tesa I have allows you to use them in a number of different configurations.

Also anyone with ideas on what this is?

Looks like another squareness comparator to me. If it was built well enough that carriage would allow you to make readings at different heights without having to set the zero each time. It would be interesting to see how accurate it is.

As far as all your probes, the B&S/Tesa type I have use a 5 pin plug with a threaded collar, are yours the same? I didn't realize Mitutoyo used the same type, perhaps that was an export only thing as locally I've always seen a different style of connector, are they really cross compatible? Private message me for possible trades :-)

[edit] Are those PFG stones lurking in the background?

 

[p3bhambama]

Dual probes can help eliminate certain kinds of reading errors, although that one does seem to use them in a fixed configuration. The Tesa I have allows you to use them in a number of different configurations.

Yeah several of mine have that ability but this is different than that. Will have to try to find a manual and see if it’s worth messing with.

Looks like another squareness comparator to me. If it was built well enough that carriage would allow you to make readings at different heights without having to set the zero each time. It would be interesting to see how accurate it is.

I thought the same at first. The vertical post is clearly hardened and looks to be precision ground.

As far as all your probes, the B&S/Tesa type I have use a 5 pin plug with a threaded collar, are yours the same? I didn't realize Mitutoyo used the same type, perhaps that was an export only thing as locally I've always seen a different style of connector, are they really cross compatible? Private message me for possible trades :-)

The B&S uses the same connector for the probe as the Mitutoyo - the one you mention. They are cross compatible but require an adjustment through the small screw on the back of the reader box to reach zero. No big deal.

[edit] Are those PFG stones lurking in the background?

They are. They’re from an eBay seller and I’ve been happy with them - quite a bit cheaper than the usual providers.

 

[Bakafish]

They are. They’re from an eBay seller and I’ve been happy with them - quite a bit cheaper than the usual providers.

Ooooh, they're only PFG stones if they come from Kinetic Precision. But yeah, the real ones aren't cheap, flatness has a price (and so does the Okamoto he grinds them on.)