Lapping It Up: Setting up for precision hand lapping

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In which we learn about making and using cast iron laps and diamond slurry to achieve high finish and high accuracy surfaces in hardened tool steel. And have fun doing it.
Robin Renzetti: ‪@ROBRENZ‬ on YT and / robinrenzetti
Tom Lipton: ‪@oxtoolco‬ on YT and / oxtools
Adam Balogh: ‪@laneymachinetechclassroom‬ on YT and / laneymachinetech
Referenced videos:
Tom Lipton: Making Flat lapping plates 1 - • Making flat lapping pl...
Tom Lipton: Making Flat lapping plates 2 - • Making flat lapping pl...
Tom Lipton: Making Flat lapping plates 3 - • Making Flat lapping pl...
Robin Renzetti on the PFG Live, on lapping: • PFG IG Live 2022 0410 ...
Adam Balogh on the PFG Live, on lapping: • PFG Live 2023-0115: La...
McMaster-Carr:
The Cast Iron plates - www.mcmaster.com/8588T23/
Hyprez Diamond Lapping Slurry, 3 micron: www.mcmaster.com/4857A47/
---
ERRATA:
Robin Renzetti (‪@ROBRENZ‬ ) makes a very good point:
"Remember that the straight band only shows "straightness" not flatness. You must align the bands a second time 90° to the first to access straightness in that direction to determine "flatness".
Only one reading is like using a repeat o meter on a surface plate oriented parallel to one side only. The flat is showing all the information in one orientation but curvature 90° to the bands registers as variation in band spacing which is not easily discernible by the human eye."
Thank you, Robin!!
---
Links for products/designs mentioned are at pfg.gg/links
Follow me on Instagram at "spencer_webb_nh".
("PFG Stones®" is a registered trademark of Kinetic Precision)

Опубликовано:

24 янв 2023

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Комментарии : 61

@johnyoungquist6540 10 месяцев назад

Inspired by Tom Liptons 3 plate video I bought 3 8 inch rounds from MCmaster turned them round and flat. Then ground them flat. Then made a plate holder for my CNC mill. I programmed the grinding motion and went through several grits using the 3 plate sequence. Hours of grinding was done I used a combination of linear and rotary motion. The results were extraordinary with no hand work. Using the CNC machine is well worth it, In high school I made a telescope mirror but made a grinding machine first. Just lazy I guess.

@KPNH 10 месяцев назад

Brilliant!!

@jacquelinesears1770 6 месяцев назад

i have been looking for a good explanation of reading what the optical flat is telling me that was the hands down best one period thank you

@KPNH 6 месяцев назад

Glad I could help!

@cylosgarage Год назад

Wonderful lapping content aside, super impressed by that dbit cutter! Didn’t look like there was hardly any burr at all

@KPNH Год назад

Thanks! Yes, that cutter did a great job.

@JohnGrimsmo Год назад

Absolutely fantastic Spencer, thank you!

@KPNH Год назад

Thank you, sir!

@AlmostMachining Год назад

Great job Spencer !!!

@KPNH Год назад

Thank you, sir!!

@Flatlapper Год назад

Hey there, just found your channel. Right up my ally. Not a ton of good lapping explanation content out there. The Oxtool series was quite good. It's great to see some new stuff being posted ! I'm looking forward to following along. keep up the great work Sir!

@KPNH Год назад

Thank you! Welcome aboard!

@geckoproductions4128 8 месяцев назад

thanks for the explainer about optical flats

@KPNH 8 месяцев назад

Happy to help!

@WallaTool Год назад

great video! lol nice intro

@ronwhittaker6317 2 месяца назад

Love Robbin silly

@rusmooseos976 3 месяца назад

So nice, ussr glasses =) beautiful

@KPNH 3 месяца назад

Thank you 🤗

@chrisj4570g Год назад

I played bass for Lap It Up.

@KPNH Год назад

Remember the hit song "Baby Embed Your Diamonds"? Good times.

@emislive Год назад

Nice work! This better illustrates what Robin was talking about with two plates in use. Without a decent surface grinder to get close enough, it still seems one needs to start with the three plate method. Is there a controllable way to go from the lathe to flat enough to lap using only two plates and no grinder? Also, aren't you committed to the coarsest grit you used? I expect some diamond would embed into both laps when conditioning with the 3μm slurry. The abrasive will degrade over time, but one stray particle can create scratches when moving to the finer grits. Looking at how straight those lines are, I think you are seeing real wringing! Wringing is supposed to work without oil in vacuum. Do you have a vacuum chamber handy?..

@KPNH Год назад

Thank you! 1) Yes, see Tom Lipton's video(s) via the links in Description. He uses only a saw and a lathe. 2) Yes, embedding is an issue. My plan is to dedicate a pair of laps to one size/type grit. 3) I do have a vacuum chamber, but I know what *real* wringing feels like and I think I need to lap at a finer grit. That is why I just got five more disks to make lapping plates. I will be able to have 3-, 1-, and 0.25-micron dedicated sets. Good gage blocks, cleaned on a PFG Stone will wring like crazy. I want to achieve that.

@Sleepingsaloon Год назад

@@KPNH any issues with diamond embedding in the A2 discs?

@KPNH Год назад

None. The rule in lapping is that the lap is softer than the work. This is why. The A2 was RC 55 to 62. My dirty little secret is that these discs were part of a six-disc set where I was really testing tempering temperature vs. hardness. Note the four hardness test point visible around the stamped numbers. After that they were used for my "five disc" test on the grinder chuck. Now they are the lapping test subjects. Re-use, Recycle, people!

@ashreid20 Год назад

@@KPNH is there any hope cleaning the plates of embedded particles? I read somewhere about using an ultrasonic bath. Or do you think that is a fools errand? Also, I'm struggling to find water soluble slurry, I can only seem to find the sringe of oil based diamond paste. Do you you have any experience/comments on the difference? (If this covered somewhere else, just point me there)

@ashreid20 Год назад

I should have said: Oil based diamond paste and scallion carbide powder and im in the UK

@dimsum5567 8 месяцев назад

Amazing optical flats from the USSR with a quality sign 😂

@KPNH 8 месяцев назад

Bought those a while ago on eBay. They're good.

@user-rw7xn3fo1t 8 месяцев назад

Nice work. What was the angle of the d-bit cutter and how deep/far apart are the grooves?

@KPNH 8 месяцев назад

I believe 30-degrees, 0.03" deep and 0.25" spacing. It's not critical.

@PaulMorley1 Год назад

Spencer, just to confirm I have it. 2 things... Instead of 3 plate method to maintain flatness of laps, use 2 plates + periodic measurements. Lap on bottom plate but when convexity or concavity is measured, flip the plates and condition until measurement is same/flat on both?? As for the diamond slurry, based on the above will you essentially now dedicate 2 plates for each diamond grit size due to grit contamination?

@KPNH Год назад

The "three plate method" refers to auto-generation of flatness, and also calibration. But, maintenance of laps is a two-plate system. The "bottom" plate tends toward a convex shape, while the conditioning lap on top becomes concave. Without trying to go into details, that allows you to drive the work piece toward concave or convex as needed and observed by measurement. Yes, I dedicate a pair of laps to one diamond size.

@ParallelTransport 2 месяца назад

Given how cheap USSR flats are and how expensive monochromatic sources are, do you have any advice on budget-friendly light sources for the home gamer?

@KPNH 2 месяца назад

Seek the Monochromatic rabbit hole at pfg.gg/links

@ParallelTransport 2 месяца назад

@@KPNH Thanks! Looks like it'll be interesting reading!

@howtoguro 2 месяца назад

I’ve tried running a laser through a marble or something that spread the coherent laser and that works pretty well.

@ParallelTransport 2 месяца назад

@@howtoguro Yeah that's kinda what I've been thinking. My biggest concern is how to know if you've spread the laser light enough to be safe. But I'm pretty conservative with regard to injuries, especially with my eyes.

@howtoguro 2 месяца назад

@@ParallelTransport You could just wear laser shades. Even really typical clear safety squints provide some protection against lasers. Full nuclear mode would be to view it from a secondary camera and monitor. Sadly, powerful lasers are too common. I actually bought a red laser point for a “Cat Toy” because I figured it would be weaker, but it was a class 3R so be really careful.