Drawer runner choice for 'normally open' use?

[jkn]

Hi All I have an office unit with a slide-out 'keyboard' shelf. This is just a piece of 18mm MDF with drawer runners on the side. The other part of the drawer runner is mounted to metal plates which 'hang' down from the body of the unit. Nothing fancy, and pretty cheap.

The runners have become pretty worn over the years and sliding the shelf in and out is now pretty 'graunchy'. I am thinking of replacing the runners. But in this application the forces are bit different to most drawer runner uses:

- most force is applied to the sliding shelf part when it is extended

- there is a larger degree of lateral 'tilt' force on the shelf than on most drawer situations

Any thoughts about the best kind of runners to fit as a replacement here?

Thanks a lot

Jon N

[Theo]

You can get industrial slides - Accuride is a popular make:

There's all kinds of variations - removable/non removable, different depths of pull-out, self-closing, locking in the out position, etc.

They aren't necessarily cheap but they're designed for things like having a

50kg server hang 1m out of a rack while someone tinkers with it, and then push it back in. They definitely don't sag when that happens.

The only thing they aren't always good for is side-to-side forces - they're designed to be attached to two rigid objects, but there can be side-to-side wobble when the server/etc is fully pulled out. It's not a problem when say 90% pulled out.

Theo

[Chris Green]

The standard kitchen roller bearing runners from such as Blum and Hettich can now be found with 30kg and 50kg ratings, they're not all that expensive either, typically £5 to £10 per pair.

[Brian Gaff (Sofa]

I was going to say, many moons ago when VCRs were big and heavy beasts there were lots of cabinets with pull out shelves with runners that were really solid and durable, and these were flatpack furniture. looking back they used a lot of nylon rollers in the main, in a metal pressed steel section. No obvious problem when mechanical keys were pressed or top loading covers shut either. Brian

[Dave Plowman (News]

A keyboard shelf hardly needs to be engineered by Harland & Woolf.

You'll find roller bearing ones to do the job in most sheds.

[Nick Cat]

There are 3 main types

1. Plastic bar. Not at all robust. Very cheap.

1. Metal strips with a wheel on, mount to underside. Not robust.

2. 2 Metal bars with ball bearings between. They can & do fail, but are at least a good bit more robust than the other types. As someone advised, go for high load rated ones, anything less doesn't last well long term. They normally run in slots, but I expect they could be mounted under if one had to.

NT