What do your shim packs consist of? 1

[dtn6770]

I'm curious as to the different practices used to establish the content of equipment mounting shim packs. The go-to-guy here on the subject offered the following advice:

0.250-inch total made up of
qty. 1 of 0.125-inch SS plate
qty. 4 of 0.020-inch SS shim material
qty. 3 of 0.010-inch SS shim material
qty. 3 of 0.005-inch SS shim material

API RP 686 doesn't go into that detail but has this to say:
5 shims max. under each equipment support foot
at least 3 0.125-inch shims under each support foot
0.500-inch maximum shim stack height
only 1 0.125 or thicker shim per mounting foot
minimum shim thickness of 0.002-inches

Another source...
minimum shim thickness of 0.005-inches
qty. 1 of 0.062-inch SS shim material
qty. 1 of 0.031-inch SS shim material
qty. 1 of 0.025-inch SS shim material
qty. 2 of 0.015-inch SS shim material
qty. 2 of 0.010-inch SS shim material
qty. 2 of 0.005-inch SS shim material

Anyone know of good reference material?

My applications are with reciprocating compressors driven by industrial gas engines or motors.

 

[electricpete]

I don't think it matters, other than the obvious: the fewer the better.

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[Tmoose]

Some have reported good results with non-metallic shims, but I'd only use stainless steel shims for extended service.

Final combination to include Minimal shims under 0.02 or so inches thick

 

[byrdj]

What is available always dictates what I use

 

[Artisi]

I would think common sense should prevail, why use a multiple of thin shims when 1 thick and 1 or 2 thin ones do the job.

 

[unclesyd]

Here is what is generally available off the shelf. If you need something thicker than 0.125" other work needs to be done prior to aligning and shimming.

http://www.precisionbrand.com/products/default.asp?p_catid=456&show_prod=42996

 

[dtn6770]

Thanks for the site link, unclesyd. It'll give me a feel for commercially available packs.

We have custom packs made for the compressors and engines we use on a regular basis. History and experience has refined the pack contents to what I would term as efficient selections.

We've recently added an unfamiliar engine to our product line and am having to figure out a starting point, shim pack wise. I'm sure it will evolve but I was mainly curious as to what other folks did.

 

[unclesyd]

There are several other suppliers of "shim kits". It may pay to look around if you need customs kits.

I kinda miss the good old days when you had to cut your own shims along with your finger.

http://www.accushim.com/shim.html

http://www.metalshims.com/store/ms_precutshimkit.html

You might also want to also take a look at this site.

http://www.laminatedshim.com/ls/Products/material.aspx

 

[dimjim]

In order to order the correct range of shims,
you have to know the hi and lo values, and
then make certain the shim pack will cover
that range by using the multiple values
within the shim pack.

 

[RebelBrill]

Things to consider when designing or specifying a shim pack are:
1. What is the minimum pack thickness required?
2. What is the maximum pack thickness required?
3. What precision is required of the pack thickness?
4. And, as has been said, minimize the number of shims to live within these constraints.