Oil sight glass

[Whittler]

Hi, I am building a model 125cc 9 cylinder Wright Whirlwind J5 radial. I need to source or make a sight glass to check oil level in the planetary gearbox. The wall thickness is 4mm Aluminium, with no space on the internal side for a nut. The hole diameter should ideally be about 8mm. I haven’t been able to find anything so far on the Net ‘off the shelf‘ and my idea so far is to make a threaded plug probably 5/16 40tpi in brass and bore through to accept an acrylic plug which would be fixed in place with epoxy. The acrylic plug in this case will be small in diameter, and not sure how visible the oil level will be, and also not sure about the epoxy fixing. I did think to make the complete plug from Acrylic, but think to cut the fine thread needed might be tricky.

Anyone have better solutions.

Thanks in advance

Paul

 

[Ken I]

I was going to use this in a different post :-

As you can see its a moulded screw in lens with an "O" ring seal - with an optical target inside it to provide contrast for the oil.
The oil level sight glass – from the lower front of the headstock (removed, cleaned & placed in view here) has an optical target which partially traps oil between its thick outer wall and the window (it can’t drain back) making it look like there is still some oil in the headstock when in fact there is none. Not that it would have helped as the oil in the sight glass was congealed into some gelatinous mass up to the original fill level. Cleaned out removed the optical background and replaced it with a homemade yellow Perspex optical background the oil can get past.

Shown above in its usual position - without the new target and overfilled so it isn't really readable.
Note: "O" ring just presses against face - so it won't handle pressure - unless properly shrouded / recessed.
I'm going to replace the target as soon as I have other issues sorted.

The other sort of sight glass is a vertical transparent cover / void over an upper and lower hole - like you might see on a hydraulic pump reservoir.

or


Make a miniature version of one of these.

FYI - hope its of some help.

Regards, Ken

 

[Whittler]

I was going to use this in a different post :-View attachment 120175
As you can see its a moulded screw in lens with an "O" ring seal - with an optical target inside it to provide contrast for the oil.
The oil level sight glass – from the lower front of the headstock (removed, cleaned & placed in view here) has an optical target which partially traps oil between its thick outer wall and the window (it can’t drain back) making it look like there is still some oil in the headstock when in fact there is none. Not that it would have helped as the oil in the sight glass was congealed into some gelatinous mass up to the original fill level. Cleaned out removed the optical background and replaced it with a homemade yellow Perspex optical background the oil can get past.
View attachment 120176
Shown above in its usual position - without the new target and overfilled so it isn't really readable.
Note: "O" ring just presses against face - so it won't handle pressure - unless properly shrouded / recessed.
I'm going to replace the target as soon as I have other issues sorted.

The other sort of sight glass is a vertical transparent cover / void over an upper and lower hole - like you might see on a hydraulic pump reservoir.

View attachment 120177
or

View attachment 120178
Make a miniature version of one of these.

FYI - hope its of some help.

Regards, Ken

I was going to use this in a different post :-View attachment 120175
As you can see its a moulded screw in lens with an "O" ring seal - with an optical target inside it to provide contrast for the oil.
The oil level sight glass – from the lower front of the headstock (removed, cleaned & placed in view here) has an optical target which partially traps oil between its thick outer wall and the window (it can’t drain back) making it look like there is still some oil in the headstock when in fact there is none. Not that it would have helped as the oil in the sight glass was congealed into some gelatinous mass up to the original fill level. Cleaned out removed the optical background and replaced it with a homemade yellow Perspex optical background the oil can get past.
View attachment 120176
Shown above in its usual position - without the new target and overfilled so it isn't really readable.
Note: "O" ring just presses against face - so it won't handle pressure - unless properly shrouded / recessed.
I'm going to replace the target as soon as I have other issues sorted.

The other sort of sight glass is a vertical transparent cover / void over an upper and lower hole - like you might see on a hydraulic pump reservoir.

View attachment 120177
or

View attachment 120178
Make a miniature version of one of these.

FYI - hope its of some help.

Regards, Ken

 

[Whittler]

Thank you Ken for your reply. I will take a look at the vertical tube system, that might be more visible than a tiny circular one. Regards,
Paul

 

[xpylonracer]

You could just use a fine tap to enable the use of a level plug, would also serve as a fill point.

xpylonracer

 

[Whittler]

Thanks xpylonracer, I had considered this and maybe simplest is best. I hope there wont be significant oil loss, so to check the level periodically would be easy enough. Thanks for bringing it back to reality!

Paul

 

[SmithDoor]

This one is simple to make any size

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Or

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Dave

Thanks xpylonracer, I had considered this and maybe simplest is best. I hope there wont be significant oil loss, so to check the level periodically would be easy enough. Thanks for bringing it back to reality!

Paul

 

[Whittler]

Thanks for the links Dave, the plastic one looks simple to make.

regards

Paul

 

[Noitoen]

You can make 2 small rectangular frames in thin aluminium, 4 holes in the corners and sandwich a rectangular window in polycarbonate. On the case yoy need 4 threaded holes to screw on the aluminium/ polycarbonate/ aluminium sandwich and a hole for the oil to get through on the bottom and the top. 2 gaskets or silicone sealant can seal the lot. This can be made in any size/shape to suit the space.

 

[SmithDoor]

Thanks for the links Dave, the plastic one looks simple to make.

regards

Paul

Most plastic to make clear like screw driver use acetone
Some times heat

Dave