Washer to fill a countersink?

Question

Washer to fill a countersink?

Mr168 (Materials)

(OP)

26 Sep 19 11:24

I have a bracket that currently fastens using a pair of 3/8-16 flat head socket cap screws with what is presumed to be the standard 82 degree taper, so the bolt holes on the bracket are countersunk. I need to mount a spacer to the face of the upper bolt hole, and need a flush/flat surface to do so. Is there a name or standard for a conical washer that is used to fill a countersink (green portion of very rough attached sketch)? I would prefer to find an off the shelf solution before having to machine one, and have only been able to locate finishing washers, spherical washers (such as those for rod end misalignment), or washers that are countersunk on top rather than flush. Any help would be much appreciated!

https://files.engineering.com/getfile.aspx?folder=cdfae4bb-d061-4762-8531-c

Compositepro (Chemical) · Answer 1 · 2019-09-26 17:57:01

Taper the end of your spacer in a lathe to match the countersink.

Mr168 (Materials) · Answer 2 · 2019-09-26 18:32:53

I'm hoping to avoid having to machine the spacer. A nicely machined spacer is provided with the part that affixes to it, and would be too short if I had to turn a taper on it.

Stick. (Mechanical) · Answer 3 · 2019-09-27 06:37:05

Contact your fastener supplier and ask them (if you don't have one already, Fastenal is probably as good a place to start as any). If they're halfway competent and such a thing exists, they should be able to help you out pretty quickly.

Tmoose (Mechanical) · Answer 4 · 2019-09-27 12:28:55

RE: Washer to fill a countersink?

Tmoose (Mechanical) 27 Sep 19 12:28

Quantity = 1 ?

3DDave (Aerospace) · Answer 5 · 2019-09-27 13:18:14

I second the compositepro answer; turn a spacer to match the countersink.
There is so little typical use for such a thing that I cannot imagine anyone putting it in a catalog.

SnTMan (Mechanical) · Answer 6 · 2019-09-27 14:04:38

Well comes to that, it wouldn't appear to be a big deal to just turn one.

Edit: Or kind of expensive but, model it and have it printed.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

BridgeSmith (Structural) · Answer 7 · 2019-09-27 14:33:16

If you only need a few, it should be a simple enough matter to get a few flat head bolts of the right size, and drill through the heads.

Rod Smith, P.E.

SnTMan (Mechanical) · Answer 8 · 2019-09-27 17:07:51

Various ways to get there. The "best" depends on how many you need, what you have to work with.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

1gibson (Mechanical) · Answer 9 · 2019-09-27 18:27:17

RE: Washer to fill a countersink?

1gibson (Mechanical) 27 Sep 19 18:27

JB weld

SnTMan (Mechanical) · Answer 10 · 2019-09-28 01:05:13

Quote (1gibson)
JB weld

AKA "Liquid Shim". Another option. Maybe not my first choice, but it'd work :)

The problem with sloppy work is that the supply FAR EXCEEDS the demand

dhengr (Structural) · Answer 11 · 2019-09-28 01:31:46

Mr168:
Why not braze the hole full, or some such, then drill it open again to the right dia. Why not drill it open to a slightly larger dia. and use a larger screw for your new fixings. The only issue should be that you provide some bearing area (bearing dia.) for the screw near the faying surface, then use a slightly heavier (thicker) washer to bridge any remaining countersink space. That bracket certainly can’t be carrying much in the way of loading.

Ron (Structural) · Answer 12 · 2019-09-28 23:33:33

Do you need a seal? If not, don't worry about it. If you do, then put a neoprene or rubber washer the thickness equal to the depth of the countersink and crank it down. It will mold to seal.

You could also drill out the countersink taper to create a flat land for the socket screw.

A Great Place For Engineers to Help Engineers

Mr168 (Materials) · Answer 13 · 2019-10-01 20:28:42

Tmoose - QTY <=2

As I gather this is not a standard/known product, I will either drill out and bush the hole, or just do as HotRod suggested and drill through a screw head to make a spacer.

Thanks all for the replies.

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Washer to fill a countersink?