Full extension drawer slides

[brianhabby]

I am planning to put my new planer/thicknesser under my bench and wanted to have it on a sliding shelf arrangement. I was thinking that I would use full extension drawer slides mounted underneath the shelf for neatness but mainly for simplicity. However, I have met an unexpected problem with my thinking (nothing unusual there).

I started looking around online and came across these from Eurofit. I was curious about the mention that the load capacity is reduced 80% when base mounted. Thinking this must mean it is reduced TO 80% I called them only to be informed that it is reduced BY 80%. So the 90 kilo capacity of the slides I had been looking at would be reduced to just 18 kilos. Since my planer/thicknesser is about 32 kilos before I even add the weight of the shelf, this is nowhere near enough. The lady I spoke to suggested I go for this one that has a 250 kilo rating which when reduced by 80% will still give me a capacity of 50 kilos.

I have never used these things before and have to say I was shocked to hear all this. Is it true that the capacity of these slides is reduced by so much when mounted underneath instead of on the sides?

regards

Brian

 

[MikeH]

Hi Brian,
Although I have no experience here it makes sense to me. The load being held through the depth of the slides when side mounted but when bottom mounted you suddenly have the weight on a 'floppy' thin metal strip. Imagine pushing down on the strips top edge when side mounted, a fairly rigid strip, as against when bottom mounted.

Does that make sense?

 

[skipdiver]

Can't you fix two sides under your bench to attach them to? I was thinking of doing a full width draw under mine for storing smaller offcuts of timber and was going to attach some boards to the legs to carry the runners.

 

[Wildman]

well I recon that nailed it. Mind you mount them vertically to slide a plinth using angle iron and problem solved.
Although locking castors are a lot easier and more flexible.

 

[brianhabby]

Mike H,

Yes, thinking about it the way you explained makes perfect sense, thanks.

skipdiver,

That's the other option of course, I just had in mind to plonk a couple of slides under the shelf an be done with it. You know how it is when you have an idea in your mind and then something like this comes along to screw up your ideas

Wildman,

I've used locking castors a lot but they are not an option in this case as the planer has to go on an existing shelf which is about 8 inches off the ground.

I will just have to think about it a bit more because the 250k slides are almost three times the price of the 90k ones.

regards

Brian

 

[MattRoberts]

Agree with vertical mounting - especially as it's shop furniture. But it's your shop at the end of the day, so go with whichever route you're going to be happy with for years to come

 

[Freddyjersey2016]

UNless I misunderstand the situation
- surely when the P/T fires up the inevitable vibration will be worse if the machine is sitting on drawer slides at full extension (whatever their capacity) - unless you fit some form of 'leg' which folds down to take the weight onto the floor - in which case the 'theoretical' load capacity is not so critical - would that help?

 

[memzey]

I'm still gobsmacked at the level of engineering that must be required to get something like a planer thicknesser down to 32kg! Am I the only one that's impressed by that? In comparison I'm sure the fence assembly on my (albeit very old) planer thicknesser weighs more than that!

 

[gmgmgm]

The 250kg / 80% rating will only be for static load. The vibrations off a P/T will be intense... I really think any drawer system will struggle. Surely it would be easier to have on solid castor wheels, even if you need to put an 8-inch high ramp in front of the workbench to allow it to run out? Or even a drawbridge!

 

[brianhabby]

gmgmgm,

I take your point & hadn't thought it through like that. The idea of a low platform on castors that I could drag it onto might just work, I will have a re-think.

regards

Brian

 

[Cretin]

I had the exact same problem a while ago Brian, a customer wanted the same set up in her kitchen with a real old bakers mixer (not a thicknesser) that was very heavy. We ended up getting an under counter integrated ironing board and modified it, fixed a 40mm worktop for the shelf and it worked.
But the unit was fixed and vibration wasn't an issue but I think if your bench isn't fixed the vibration will just pass through the runners and shake the bench

 

[Wildman]

Mike H,

Yes, thinking about it the way you explained makes perfect sense, thanks.

skipdiver,

That's the other option of course, I just had in mind to plonk a couple of slides under the shelf an be done with it. You know how it is when you have an idea in your mind and then something like this comes along to screw up your ideas

Wildman,

I've used locking castors a lot but they are not an option in this case as the planer has to go on an existing shelf which is about 8 inches off the ground.

I will just have to think about it a bit more because the 250k slides are almost three times the price of the 90k ones.

regards

Brian

just rotate the slides through 90 degrees and they will do the job

 

[sploo]

Yep - you definitely need them mounted on the sides to get the strength. Imagine cutting a piece of thin cardboard of roughly the same height and length as the slides - it'll not be that easy to bend it down if the short dimension is vertical (like the drawer slide should be used). Hold the card so the short dimension is horizontal and it'll likely sag even under its own weight.

If you had the space, you could fit one or two folding legs (that lift up, parallel with the shelf when stowed). When pulled out, drop the legs onto the floor so they provide additional support and stability - though you'll really still need to mount the drawer sliders vertically as designed.