Hand Lapping by Don Bailey
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- Опубликовано: 12 сен 2024
- How to Hand Lap a part. In this video I will show you the basics of hand lapping and how easy it is. We also have an automatic lapping machine that will be featured in a future video.
Lapping will give you the ability to make your parts extremely accurate and flat. It will set you apart from the next guy. 
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Love the way Don is so passionate about engineering and in sharing his expertise and knowledge. Nice one Don and thanks.
Thanks for watching
Thank you Don for this video. I've been machining for a long time, but have never really lapped anything, and today I need to lap a bunch of stainless parts. No matter how long you've been in this trade, no one knows everything, and I love expanding my knowledge. I'd love to learn under you. Thank you sir.
Thank you and good luck, I hope it turns out well.
@@SuburbanToolInc going really good actually, parts went from a machined line finish and dome shaped on the bottom to being very flat and can see your own reflection in them. I’m excited to show them to the customer.
Takes me back to my days of hand lapping large Air Compressor Valve Plates. The V Major Compressor had 16 valves per compressor. Each valve about 6" diameter.
Thanks for all the videos. They are very helpful and motivational. I work with manual and CNC grinders and have learned a few tricks to help at work.
Thanks Don for your time and effort
Discovered your videos a couple of weeks ago........each one brings a smile to my face! Glad to know someone out there still appreciates something so simple as hand-finishing a part. Keep it up, chief.....hope to make it by your shop next time I go to Auburn Hills for ABB robotic training!
Isn't it amazing what doing something by understanding of the complete process for fourty years will do to create a seemingly easy performance of a hellish tSK?
doesn't your hand temperature influence the shape of the part when doing this? Can it happen under some conditions?
Enjoyed the video learned a little. I do wish you guys who make these videos would be more clear on measurements. I was taught a tenth is 1 ten thousands, or 1/10,000 of and inch. But a machinist (40+yrs experience) friend of mine thought you are talking about 10 thousandth or 10/1,000. it started an argument. I think I am right. I do know the figure 8 stuff is meaningless, as it will wear a figure 8 into your lap. What is important is to use as much of the lap surface as possible, it gives a truer lap and more even wear and longer life for the lap surface.
you're definitely right, a half decent mill can face something to 10/1000, this is getting it flat to 1/10000
Don, I wonder if you would like to comment and give your opinion on something which has always somewhat puzzled me. I occasionally ;lap the soles of my woodworking planes, using a 5' x 3' granite surface plate with high quality PSA sandpaper attached to it.
No matter how I vary the lapping pattern (figure 8, diagonal, straight, whatever) the surface of the sole always comes out very slightly convex ... not by much, maybe one , one and a half thou across a width of around 2 inches. The plane soles are flat enough for the most precise woodworking, so the lapping serves its purpose, but I just wondered why they don't ever come out dead flat ?
I know the surface plate is accurate to a tenth , so it's not the plate at fault ... I get the same thing when I use my smaller plate.
I would imagine ( as I have experienced this also ) that the material paper has flex in it.For example, the higher areas of the plane will press onto the grit paper which will be compressed so the variation in pressures is not stiff enough to give < 2 / 1000 precision. I might suggest getting some lapping compound onto a surface plate and finishing the last 1/1000 via that method and see how you go>?
I have had that same issue. Turns out the paper needs to be stuck down with adhesive. AND, the paper needs to be precise. Link below
www.toolsforworkingwood.com/store/item/ST-MAF.XX
Best Matt
James Green asks how to clean up gage blocks. my recommendation would be to use a light oil ( like wd 40) on Good quality stone surface plate lapping motion until surface is clean and shining. I don't recommend using an lapping compound as size will decrease,good luck
does using half the lap witch different abrasives wear the lap unevenly? causing it to get out of spec faster?
I was taught in my apprenticeship that once a grit size has been used on a surface plate, the plate was to be used with only that grit until it was re surfaced. Is this different from your experience? Are you not worried about the abrasive being impregnated into the surface plate?
Great videos! Keep them coming.
BradenStroud You were taught correctly.
would impregnated if the grid is diamond, but for aluminum oxide may be not so much.
Thank you for the video, very informative as always! I would have loved to see the surface finish a little better, but could see at the end the reflections of the 1200 grit surface.
What I would like to know is how the lapping plate is best cleaned? Just use whatever the lapping paste dissolves in and rinse with water?
And if I understood correctly, the accuracy of the lapping flatness depends solely on the ability to grind am extremely flat surface? Or is the grinding of the plate not so critical and the lapping process kind of evens out the differences of the plate over time?
To add to Jaakko's excellent questions:
Does the lapping compound remove material from the cast iron lapping plate at a slower rate than from the lapped part, or do the plate and part wear down at the same rate?
And who makes the lapping plates you use at Suburban Tool?
Informative video Mr Bailey. Thanks much!
+Seven/Ninths Creative The lapping plate is charged with the compound and cuts the harder material. In other words the grit embeds itself into the softer material, being the cast iron plate, and cuts the harder material.Cliff
this type of accuracy has been lost in the UK, they dont teach the banes this now and thats whats wrong, thank you for the video
Its coming back dont worry.
great video very informative.
Like your stuff but the lapping plate should be "charged" and washed off before lapping, You are rolling the compound around between the plate and work which works but creates inaccuracies in the work and wears the lapping plate more. Ref Machinery's Handbook
Sir which machine used for gage block lapping?
Guess you didn't listen to him at 7:17.
Hi, interesting subject... Now one question, how are lapping plates made to be flat...?
Thanks
pierre beaudry They are ground.
You can do that by lapping 3 plates alternatively. That's actually one of the few methods to get extremely high precision with real simple devices.
Simon P
Something like making a telescope mirror, but, keeping the surface flat instead...??? Guess it could work.
Bill Lewis
I'll have a look, thanks... ;)
Now that those two sides have been used for those grits, can they be used for other grits? Or is the plate now permanently embedded with those grits?
Cross contamination is frowned upon, putting 1200 in a 600 lap will result in the 600 making marks unless its cleaned
As for how permanently embedded, im not certain
Ignorant question, but is it possible to use a sacrificial protective surface such as a glass plate over the lapping plate to prevent wear? If so, what are the tradeoffs? Also I presume there is a safe amount of hand lapping where there is minimal concern over keeping your part square.
no question is ignorant, no need to use glass plate
A surface plate is a tool that needs care and recalibration, just as the tools you build off it. It seems surface plate wear is a part of that tools life cycle and reference plates probably stored somewhere to recalibrate the ones used in this application here. The alternative is professionals resurfacing it for you every so often. Some good comments here about the best practices to lap and they typically lead to requiring more money spent and more time eg. Only using a surface plate for one particular grit, means you need more than one plate in a workshop. It is a fascinating science /skill to have a block of steel fall into such fine tolerance for a particular temperature but also how we achieve such precision machines given that small temperature variation will take out that flat very quickly.
Thank you for your excellent videos. With respect to Branden's comment, please comment on cleaning lapping plates. Regards, Earl
Earl Hughes Earl , You clean the lapping plate with mineral spirits and a stiff paint brush that the bristles are cut to approx. 3/4" long.
Thank you for the reply. Regards, Earl
Could you explain what materials are suitable to be lapped?, hardened steel, mild steel, cast iron?
Yep, you got it right. all those. basically most metals you would want a precision surface on. Granite surface plates are lapped, so you can add stone to the list. Some really soft stuff (metals) like Lead or copper can be problematic depending on the abrasive as diamond can embed in the surface and cause problems. A hardened precision surface is hardened first as the heat treating distorts the surface and is then lapped true.
How much material will be eaten up by lapping like this? Will it affect the tolerance adversely?
Good information, Thanks.
Regards
It would be helpful if you took some perfect pictures of the surface finish you are talking about and edit those pictures into the video. It's really hard to see the surface video on the video
ebrewste Good tipThanks for the input.
Even a monitor so Don could see what the video is recording would help.
2,000 grit would make that mirror shine.
Optical clear polishing is done with 25000 grit under a 30X microscope eh bro...
Thank you.
You're welcome!
would the heat from your hands affect it ? like if you were holding it in the center and the ends of the steel were more cold then the center ?
+Waffenschmiedin x It’s possible, the overall effect will depend on the thickness of the part.
thank you just curious :)
heat, oil from Don's fingers, and high and low spots on the lapping plate affect lapping. heat build up in the stock piece Don lapped caused a convex bow when hot. this is why the part was concave. as he lapped, you could see high spots on either end because hest dispertion is faster on the ends. assuming he used the same method of gringing on the stock piece as on the lapping plate, the lapping plate is most likley bowed, but not by much considering the part was check for flatness when cool.
it really depends on the thickness and material of the work piece...in addition if the the call out is less than 000200 straight, round or both...flat, external, and internal, lapping must be done within a climate controlled clean room department
Don;
You are an Animal.
Wow, hand lapping.
I love the way you use the manual machines demonstrate technique.
I would have a hard time imagining a guy hand cranking a surface grinder all day, that would be as tough as topping trees.
An Observation:
I have a 14" buffing wheel, and I usually use chromium rouge... green... for steel.
It will produce a mirror finish, really. I could polish a piece of black pipe to where you could read the fine print on a credit card processing contract off it's reflection.
But... as it is a cloth wheel... I don't know if I could achieve precision.
Finish, certainly.
My opinion is buffing would ruin the precision of a lapped face.
Unless you can do it precisely.
So... should I put a buffing wheel in my surface grinder????
Is there an end to it?
Thanks yet again!!!
Mark
I am looking for a portable solution for whetstone lapping at home. So I am searching for smallish plate made out of glass, or metal, but made of better materials and assembled better than, say: Edge Pro Apex whetstone flattening plate. It has to be at least 12" x 12" square, or a disk with at least 12" diameter with rubber borders, which could prevent dirt from spilling beyond the plate and at the same time work as non-skid "feet". Can someone steer me to a right direction?
Go to Home Depot and get a granite flooring tile and a few packs of Wet Or Dry sandpaper in grits going from as low as 40 grit all the way up to 2,000 grit. Granite flooring tiles are ground almost perfectly flat, which for taking care of your sharpening stones is more than good enough. Lap your stones using a grits lower than the grit of your stone, and then 'finish' the stone by running a block of metal over the surface if you want to set the grit back to what it used to be. Not necessary though, since the grit will just go back anyway when you start sharpening.
Good Job...
Thank you so much 😀
Sir, which machine use for gage block lapping?
Which of your products do you lap?
Wouldnt the lapping compound affects the surface plactes flatness
Over time that would be true. Then it must be refinished.
How often do you need to surface grind the plate?
b-rock It all depends on how aggressive the your grit is , how often you use it, how you use it. There are many variables.
Why is the lapping compound applied to the lapping plate instead of the part?
+John Lane It will work either way.
+John Lane Because the plate is doing the lapping.
+Andre Gross There is a lot more to it then that, Unfortunately my comment was delete a year ago. You have to spread the past e around the surface, press the grit in with a hard stamper or roler, then wash away all the loos grit and paste with a solvent. This leaves only the grit you need on the surface and allows for areas where lapped materiel can be washed away. More importantly the grit isn't wearing into the lapping plate. When lapping doesn't produce as much black streaks as before, the grits are worn down, so you stone the surface then inbreed the grits and wash before lapping again
Read the first few paragraphs on lapping in the machinery's hand book.
If you do it as shown you are wearing away just as much in the lapping plate as the part.
you would lap a hole in the plate.
What tool is he using in his hand?
It may be one of our 4 way parallels or just a piece of stock for demonstration. Thank you for watching.
can you lap tapers
be careful with using the same rag. you will cross contaminate your grits.
Can anyone please tell what does he say in 2:03 ? I'm not a native speaker and I'm trying to make a translation for this to portuguese.
"we start in this area and see how that works " He means we will start lapping in that half of the plate and will observe if he gets the results he is after
14:00 chrome rolled steel, chromoly.... anyone got chrome jokes?