Thread: Another Lapping Film Question

Ok, so I'm seriously thinking of giving lapping film a try. I currently use my 1k king to set bevels, then 4/8 Norton. Crox on leather to finish it off. Getting good shaves off the 8k. I want to see if what improvements might be made beyond 8k.

So, what lapping film micron should I get coming off the 8k? I have a woodcraft near me, and thought I would go there to get one sheet to see if I like it. I believe they sell the 3M there...

On the woodcraft website, they say the 1mic is equivalent to 8k grit (equal to my Norton) However, after reading some other threads, it seems many people say the .3 micron is too harsh.

Also, I typically use tape. Any issues with tape when using lapping film? I haven't seen any information about this in other threads...

Any guidance is appreciated on which direction I should go. Thanks!

The film is cheap enough that you might as well try different grit films and experiment for yourself rather than going on someone else's claim of what is too harsh.

There is no issue with using tape with film.

Yea, 1um film is about 12-15K, but gives a more uniform stria pattern, than an equivalent stone.

A 1um edge is/can be a very comfortable shaving edge.

First get a good substrate, a Glass or Ceramic, 3X12 tile, I get glass tiles from Lowes, about 5 bucks. Lap the tile flat with 220 and 320 wet & dry or diamond plate. Glass is not flat, like folks think.

The flatter the surface the better the film will stick.

Cut your film with a paper cutter or straight edge and razor knife. Wet the glass, make sure it is clean and rinse the back of the film, (smooth shiny side) and place on the substrate.

With the razor, smooth the film to the substrate while holding one end. If you feel anything under the film, remove wash the substrate and the film, or you will tear the film, making it unsuable.

Then squeegee the water and air from under the film. Once flat on the substrate, the film is firmly attached and you can hone on it just like a stone. Yes, use tape.

Film will cut more aggressively and leave a super straight uniform stria pattern and edge.

If the 1um edge is too aggressive for you, cut a piece of copy paper to the film size and put the paper on the substrate between the film and substrate, Wet the substrate, lay down the paper, wet the paper, lay down the film and squeegee.
The paper will cushion the film and polish the leading, 1/3 of the bevel and edge. That for me is a very comfortable shaving edge.

Try a piece of .3um, but for me, it just is too sharp. .3um is about 50-60k grit.

You do not need PSA film, it is a pain in the butt to apply. A single piece of film will hone 10-20 razors, depending on the condition of the bevel and how much pressure you use. When done peel off the film dry and store, (business envelope).

If you like film Thor Labs is the best source for purchase, and the sheets are larger 11X9 in. Film is great for problem, super hard razors.

Thank you Euclid. I found a vendor that sells 25 sheets at a time but it is aluminum oxide not diamond. Which do you prefer? Excellent instructions by the way, I appreciate it very much.

Yup, you want Aluminum Oxide, not Diamond. Diamond is about 10 times the cost for the same performance.

AO film also comes in much larger sheets. Also do not buy PSA film.

Unfortunately its rare to find the lapping film in small quantities so perhaps you can find another member to sell/give you just a sheet to play with and practice. I take my lapping film and just lay a third of it over my norton to get essentially 3 disposable sheets per page. Works great.

I may have a piece I can send you..send me a pm

From the 0.3 micron tape I go to .25 micron diamond paste, iron oxide on leather, then a Miller leather strop. Shaving off the 0.3 is not smooth enough IMO.

You have a lot going on. You should get a very comfortable edge a 1um. At .3um the edge is harsh from excessive keenness.

It is not just about grit size; grit shape and substrate hardness play a large factor.
Using .25um diamond after .3um film is making the edge harsher.

Skip the Diamond, you don’t need it, and either finish on 1um with paper or strop on Chrome Oxide and shave no leather needed.

Thank you. That makes a lot of sense. Will do.