How To Best method to reduce thickness of a PB washer???

[photoman12001]

I'm hoping someone can give me some tips on the best way to reduce the thickness of a phosphor bronze washer. I have some 1/4"ID X 1/2"OD X .015"TH washers from USA Knife Maker and I need to get the thickness of one down to 0.0125". The next size down from the store was 0.010". I tried running it along a Smith's sharpening stone for a while but never saw any reduction in thickness. I did get some decent polished surfaces though. I then tried some 320 grit sandpaper but mostly just took skin off my fingers (no good way to grip the washer).

Does anyone have any advice?
Did I mistakenly assume this would be a little tedious but doable?

 

[Wowbagger]

Oh piece of pie. Chuck up a length of metal rod into your metal lathe chuck. Face the end square.
Shellac the washer to the rod.
Take a skim pass to face the washer flat.
Measure the remaining thickness of the washer.
Face off everything that doesn't fit the description of the thickness that you need.
Dissolve the shellac to remove the washer.
Piece of pie.

Alternatively you could counter bore a recess into a metal plate to the depth of the washer thickness you like, preferably a steel plate and file or sand the amount protruding above the plate off the washer.

Just goes to show what I always say :
In addition to every human being equipped with a good Swiss Army Knife at birth they should also be issued a TIG welder and a medium size metal lathe. Other wise the poor thing will be helpless and doomed.

 

[photoman12001]

Oh piece of pie. Chuck up a length of metal rod into your metal lathe chuck. Face the end square.
Shellac the washer to the rod.
Take a skim pass to face the washer flat.
Measure the remaining thickness of the washer.
Face off everything that doesn't fit the description of the thickness that you need.
Dissolve the shellac to remove the washer.
Piece of pie.

Alternatively you could counter bore a recess into a metal plate to the depth of the washer thickness you like, preferably a steel plate and file or sand the amount protruding above the plate off the washer.

I should have mentioned, this is definitely a "kitchen table" type of project. I don't have access to a lathe currently (hopefully in a few years).
Based on your response I'm guessing I set my sights too high on this given my available resources.

Thank you for the information though.

 

[Wowbagger]

Photoman,

Mostly that was tongue in cheek. Very few people will be able to comply with that.
No doubt others here have a more simple and practical approach, though probably less fun.
Sit tight.

 

[Sonnydaze]

He's really good. U can counter BORE A HOLE IN hardwood deep enuf to drop in washer and then use a file. Smooth with sandpaper.
Buy counter BORE at Lowe's cheap and use vise and electric drill.
Heck, bud, u CAN do this.
Good luck

 

[BD_01]

I've used the sandpaper-finger method to thin them out, starting with I think 600 and working up to 2000 for finishing. I used a figure-8 pattern with two fingers and moved my fingers 90 degrees every 6 passes or so.

I wasn't using a micrometer, just trial & error. I was pleased with my result, but really don't know how much thickness I ultimately removed (I've done it to adjust centering, so maybe it was less reduction than you're after). I think the washer may have been a bit larger than 0.5" od, which would explain why I still have fingerprints.

Any chance you'll share with us what you're working on photoman12001 ?
Anyhow, I'm kinda curious to see what others have done too.

 

[photoman12001]

Any chance you'll share with us what you're working on photoman12001 ?
Anyhow, I'm kinda curious to see what others have done too.

Sure. Basically I've got a small Sebenza that is off-center and has too much blade play closed and open. The previous owner Schotchbrited the scales which I like, but I'm pretty sure he did the insides too which is obviously no good. I'm sure CRK will not fix the issue due to this so I figured I would try to fix it. If I can't then I'll send it in with a couple of others that I'm sending to the factory anyway and see what happens.

A couple of lessons here:

1. Throughly inspect any used purchases. I am usually relentlessly meticulous in doing this. The Sebenza slipped through because I also got a Graham Razel from the same deal with a badly abused blade edge that wasn't mentioned in the ad. It couldn't even cut printer paper and had some bad dings. I became focused on fixing that which I did with pretty good results on my Sharpmaker. The seller did offer to take it back but they don't come up that often and the price was good enough to deal with it. I'm now happy with that one. It's been long enough now that I wouldn't feel right trying to return the Sebenza.
2. If you're selling a knife, inspect it as though you're the buyer when you list it. If it has an issue, mention it. I have bought several knives lately with issues like this, several with edge damage not mentioned. The damage is usually pretty obvious and sellers say they didn't notice. Honestly, I've had enough issues lately that I think I'm going to take a break from buying stuff. It has taken the fun out of it.

This Razel was worth the trouble. It's a neat little knife. The edge still has some dings but they are greatly diminished. It desparately needed cleaned too and the action is nice now. This and my small Inkosi are pretty much always with me.

Before

After

 

[photoman12001]

I've used the sandpaper-finger method to thin them out, starting with I think 600 and working up to 2000 for finishing. I used a figure-8 pattern with two fingers and moved my fingers 90 degrees every 6 passes or so.

I wasn't using a micrometer, just trial & error. I was pleased with my result, but really don't know how much thickness I ultimately removed (I've done it to adjust centering, so maybe it was less reduction than you're after). I think the washer may have been a bit larger than 0.5" od, which would explain why I still have fingerprints.

I might pick up some higher grit sandpaper and try again with that. The 320 is just too course and the the washer just catches on the grains.
I keep thinking back to my fiber optic termination days and wishing there was a metal puck into which I could place the washer for running against the abrasive like I used with Hot Melts. That would be perfect but I'd need a setup like Wowbagger mentioned to make it. Maybe one day...

 

[RayseM]

Why can't you just hot melt it to a block of flat stone, wood, or metal. Run your abrasive (a diamond plate or coarse wet stone, or metal file) OVER it rather than running it across the abrasive. If you had some thin stock of something else that was the target thickness or a bit less you could also glue that to your pad around the washer to provide a balance for the abrasive rub from above. That way you would enhance your ability to keep the washer an even thickness because your abrasive would not be rocking or tipping as you pass it over the washer.

Just a thought. I haven't tried this.

Ray

 

[BD_01]

I've used the sandpaper-finger method to thin them out, starting with I think 600 and working up to 2000 for finishing. I used a figure-8 pattern with two fingers and moved my fingers 90 degrees every 6 passes or so.

I'll add to my post that I use wet/dry sandpaper. Wet seems to help things glide better.

 

[dauntless15]

2000 grit sandpaper , light pressure figure 8 pattern . . that's how crk does it . or send it in and have them take a look.

 

[photoman12001]

Thanks guys, I'll pick up some finer sandpaper and try with that.

RayseM , I'd prefer not to fix the washer to something because I'll be testing for fit as I go: remove a little metal, test function, repeat. I have target thickness in mind but I might not need to take it down that far.

 

[tiguy7]

I just put the washer on my fingertip and go after it with a Spyder Sharpmaker trangular prism. There are several grits available. The prism is only 1/2" wide so there is no finger contact. Be sure to rotate the washer frequently.

 

[REK Knives]

Sure. Basically I've got a small Sebenza that is off-center and has too much blade play closed and open.

So the washers that came in the sebenza are around .010" thick, you bought some .015" thick ones and want to thin them down a few thou? Worse comes to worse and you can't do that you could use one .010 and one .015 =) Would hardly be noticeable. I can check and see what I have laying around... often times there is a +/- variance of a few thou so I could measure and find 2 identical ones that are around .012" thick possibly...

 

[photoman12001]

I picked up some 600 grit wet/dry sandpaper last night and that worked well using some water. I got the washer down to 0.0130". The action is too tight at that thickness but I'd like to try and get it down the rest of the way using a sharpening stone. I ordered a Spyderco doubled-sided (medium/fine) stone that is 1" x 5" x 1/4". T tiguy7 , I wanted to use this instead of my Sharpmaker stones because it's wider. I initially tried using those but due to the narrow surface I was afraid I'd remove metal unevenly despite rotating the washer frequently. Hopefully that stone arrives soon.

REK Knives , that's a good idea. I didn't think about using two stock washers of different thicknesses. I'm going to order some more parts from USA Knife Maker so I'll probably pick up some washers to try that in case this fails.

 

[photoman12001]

So I was able to fit a washer to replace the small one that seems to have rectified the centering and side-to-side play issues. I'll add some details a little later but in summary:

• All told it was about 3 hours of work
• It took 2 attempts because I took the first washer's thickness down too far by 0.0005" and that was enough to make a difference
• The tips of my first and middle fingers are painfully exfoliated
• It also required removing material from the washer's inner diameter which was time consuming