Compressor Mounting Question??

[tcb-1]

okay, the mechanical engineer in me is scratching my head.

I have a Viair 400C compressor. Looking at the hardware to mount it with make me a bit nervous. It mounts via a grommet/brass bushing in 4 places. The i.d. of the grommet is approx. .20", which leads me to believe I will use 3/16" hardware.

hummm, a bit skimpy for a 5 lbs piece of equipment that's usually vibrating during run time.

so my questions are:

has anyone "hard" mounted their compressor (take the grommets out? if so, any failures due to vibration?

anyone had issues with the bolts being TOO small?

just trying to rectify something before I figure out my installation and wondering if I need to drill larger mounting holes.

thanks gang!!

[lolife99]

Doug,... I think Viair recommends them to be rubber mounted.
Are you sure a 1/4-20 bolt won't go thru the mounting holes?
I would just use nylon lock nuts with them.

(or maybe a 6mm bolt)

[tcb-1]

Keith,
The bushing .i.d is .197/.200, so I'm guessing 3/16" hardware is what Viair had in mind. As a matter of fact, the hardware they provided with the compressor is reeeeeeal low quality, black oxidized grade 2 (if even grade 2).

guess I'll just go with your recommendations with ny-lok nuts and keeping the rubber mounts........ and grade 8's (if available).

[lolife99]

Looks like a #10-24 or #10-32 bolt.
Maybe something with an allen head or button head.

[tcb-1]

yep, think your right. looks like #10-24 UNC

why is it that I still think that's just too small?

oh well.... thanks for you thoughts, Keith

[jlaird]

I agree. I think the mounting hardware sucks. I bought i believe 10-24 stainless bolts with allen head, lock washers and loctite. Nylocks would work too.

[N2TRUX]

I won't try to advise you about the mounting hardware since it's been covered. I will tell you that you do not want to solid mount it.

Mine is mounted on the rear most crossmember, and it still vibrates all the way to the front.

We tried tightening it down once.....BIG mistake.

[tcb-1]

looks like rubber mounting is the ticket then.

I appreciate everyone's input!

[MTCHEVY]

My bolt charts say that a #10-24 bolt (grade 2) has a proof load of 55ksi (55000 psi) and a 720 lb clamp load. It think 4 should have no problem holding a 5lb compressor? Look forward to see more pics!

[dznucks]

i thought the same thing about mine. i came across some titanium 3/16" fasteners. should hold.

I welded up my compressor bracket last weekend. i decided to mount mine in the far back corner, behind the passenger side tire. I have made rubber isolators for the bracket too. hopefully having two sets of vibration isolation will help.

[tcb-1]

Originally Posted by MTCHEVY

My bolt charts say that a #10-24 bolt (grade 2) has a proof load of 55ksi (55000 psi) and a 720 lb clamp load. It think 4 should have no problem holding a 5lb compressor? Look forward to see more pics!

55k psi tensile is per square in. #10 capscrews, at the major diameter, has .0265 square inches of material. so in fact the tensile strength is 1462 psi.

and these numbers are under a static load. the compressor, by nature, should be considered a dynamic loading (to be safe).

[MTCHEVY]

10/4