Backyard Shop Tip - Decreasing The Thickness Of Washers And Spacers

idbruce

This tip goes hand in hand with one of my previous tips concerning washers, which was:

Backyard Shop Tip - Enlarging The Inner Diameter Of Washers And Spacers
http://forums.parallax.com/discussion/157276/backyard-shop-tip-enlarging-the-inner-diameter-of-washers-and-spacers

As mentioned in the other article, if you like to build things, such as robots, then there is bound to come a time when you need to reduce the thickness of a washer. Normally I am very critical about thicknesses when ordering washers for my prototypes, but occasionally, when building a shop tool or a special jig, I will attempt to use washers that I have on hand, as was the case today. Basically I needed a shim, with a predetermined thickness, to fit a 10-32 screw. Over the years, I have had the need to file several washers, and it was always drudgery, and today was no exception. I started filing the washer, by holding it down between my thumb and index finger, meanwhile pushing it back and forth across the file.

There has to be another way!!!

And indeed there was. I decided to attempt my filing process with a pencil eraser, and it worked very well. I wish I had thought of that long ago, because it would have saved me a lot of grief. After finishing the filing process, I came to the conclusion that larger washers could be handled the same way with larger erasers, or so I think.

Phil Pilgrim (PhiPi)

Bruce,

I bought one of these more than 20 years ago:

https://www.rsci.com/general-mill-supplies-artus-corp-plastic-shim-stock-pss10a

And I have yet to make a dent in my supply. With a cheap set of hole punches from the local office supply store and a pair of scissors, it's a cinch to make washers of any thickness.

-Phil

idbruce

Phil

Yea, that appears to be a handy assortment for shimming and such. It would be nice if they told what sizes come with the order.

0.0005in. that's pretty thin.

Thanks for the tip.

EDIT: I only mentioned one size, but I realize that it is an assortment

Phil Pilgrim (PhiPi)

Here are the sizes in my assortment:

.0005, .001, .0015, .002, .003, .004, .005, .0075, .010, .0125, .015, .020, .025, and .030.

That's only 14, though, so they must've added a size since I bought mine.

-Phil

xanadu

Bruce, my fingers said thanks!

Ttailspin

Those small but very powerful magnets make a nice finger hold on little steel washers,
And a small piece of Play-doh clay will often work for the larger washers, believe it or not.
Or, you can just keep putting Band-Aids on your finger tips, Some states have laws against filing your fingerprints though...


-Tommy

Beau Schwabe

I was using a machine just today that can take off as little as 1 micron per pass... we were using it with 2 passes taking off a total of 100 microns.

The only thing holding the sample in place is WAX which easily comes off with acetone. The precision of our equipment is a little ridiculous for your application, but all you need is a high speed dremel (we were running at about 25,000 rpm on Aluminum) and a good mounting apparatus that you can control the Z-axis to a specific (premeasured) depth and your done.

idbruce

@Phil - Thanks for getting back to me with the sizes. That is a nice array of sizes and it would certainly tackle most low torque shimming applications. In fact, I have just the use for that in another application, so I really appreciate your input.

@xanadu - You are welcome. I know my fingers certainly appreciated the break from the drudgery

@Tommy - Play-doh, magnets? I will try almost anything once, so I will keep it in mind.

@Beau - I think wax would probably well for cutting operations, such as milling, where small layers were consecutively removed, but I believe it might gum up files.

@everyone - While writing these responses, I came up with another idea, which I will likely use in the future. To maintain workpiece rigidity during filing operations, I am now thinking the best way would be to turn down a small section of round scrap aluminum, to match the inner diameter of the washer being filed. See attached image.

koehler

Never had to file down a washer, however:

1. Round one end off of a 1/4" piece of round stock, use that to press washer against
grinder/sander?

2. Tack 2 thin pieces of stock at 90' - L
Drop washer in corner, and prop 3rd side with another thin piece of metal
Or disregard that step, and just sand so that direction is towards inside corner

JLocke

Grainger carries shim stock assortments, too.

Beau Schwabe

You do realize that any grinding method is likely to remove any protective layer that would normally be there to prevent the washer from rusting?

idbruce

@JLocke - Yea, McMasters also carries shims, which is whom I normally order from, but I am talking more about a spare of the moment or emergency type of requirement. McMasters offers peel-off shims, which seems a little appealing.

@Beau

You do realize that any grinding method is likely to remove any protective layer that would normally be there to prevent the washer from rusting?

I am assuming that question was meant for me However you are assuming the use of washers that contain iron. There are a lot of washers that will not rust, even without a protective coating, just in case you were unaware

However, your assumption was correct, I was talking about a steel washer with a zinc coating, but as it pertains to this specific washer, I do not believe I have too much to worry about. The spacer I was working on, will be directly underneath an oiler used for threading and drilling purposes. and I am certain it will always have a coating of oil, but that will not always be the norm.