A New Approach to Drawer Slides

[Retired Tanker]

I started this thread in "Vehicle Mods," and got a recommendation to repost it here.

So, after looking at many, many fine works of craftsmanship, I still had a few lingering concerns over the various approaches to drawer slides. The skate bearing is obviously the way to go, so that's a no-brainer. But after looking at so many designs, I noticed the loss of volume due to the intrusion of the various bearings, bolts, and associated hardware. Not to mention the space under the drawers.

While musing about a more efficient approach, my wife asked me to move a rack in the oven...and Ka BLAM!! It hit me.

Below is a design the moves the bearings below the drawer and into the deadspace created by the bottom brace. It spaces the bearings in a logical fashion with more bearings near the front to support the extended drawer. The key is a short piece of channel steel that will fit between the rear-most bearing and the next one forward, but as the drawer is pulled out and passes the "tipping point" it rests on an increasing number of bearings. This also acts as a "stop" to keep the drawer from being pulled all of the way out. To remove the drawer, empty it, push it all the way in, and then slowly pull is out while trying to tip it forward. When the channel steel passes the rear-most bearing, it will lift clear and you can pull the drawer out. Obviously the sides of the drawer will have to be short enough to allow this.

By putting the bearings at the bottom of the uprights, you have less chance of bowing due to carrying the weight.

Below is the original layout, and then a couple of sketchup views:

 

[Lucky j]

Much better with the 3d.

Interesting! Keep the evolution coming!

 

[Dr. Cornwallis]

This is a cool idea... So the bare wood rides on the skate bearing?


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[Retired Tanker]

This is a cool idea... So the bare wood rides on the skate bearing?


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So, one of the cool things about Sketchup (or any other CAD modeling) is you find things. Bearings on bare wood, for example.

The other thing I noticed is that the bearings would hit the edge of the guide as the drawer is moved (bump, bump, bump...). So, I need to add material there. Probably a metal strip along the length of the drawer would help both issues...

 

[Goodness181]

Nice keep us updated. Do you have this on your current drawer set up yet? If so would love to see it. I'm working on my blue prints for a drawer setup right now but still on paper. Its going to be my winter project.

 

[Retired Tanker]

I've got the bearings. Getting the plywood this weekend.

 

[DanCooper]

Great idea, thank you for sharing. I'm glad I saw this before I started building this weekend. Now I think I better wait a week or two to see how your idea works out . . .

 

[Retired Tanker]

I worked on the platform today. I'm going to post the build pix in a new thread.

But I did experiment with mounting the bearings, and I think I'm going to go with T-Nuts on the outside support and 1.5" bolts on the center support. There will be 2 bearings on the center, one on each side of the support. I'll cut the excess bolt off and use lock-tite on the threads. The first bearing is 2.5 inches back from support rail, then 5.5, 8.5, and 11.5. That gives me 4 bearings holding the 12" guide when the drawer is at full extension. The next bearing is 18" back, then 25, 32, and the last one is at 45.5 inches back. That creates the gap for the guide to fall through.



I laid out the lines to expose about 1/8" above the rail. I would have loved to try for 1/16, which is the standard for fine furniture, but...



Then I drilled pilot holes to keep the larger bit from "traveling"...



Here's some examples for the mounting. I used 5/16" bolts and 1/4" washers between the bearing and the wood (the 5/16 washers were larger than the bearings!).



I'll post the pix of the TNut installations tomorrow. It's time for dinner...

 

[Retired Tanker]

I didn't get much done on the drawers. Spent most of my time on the frame. I promise to get to them next Saturday, although I might get some done in the evenings this week.

I did finalize the decisions on the bearing mounts. I'll use 1.5 inch bolts for the center upright and 1 inch bolts with 3/8 inch deep TNuts on the sides. I'll grind off the excess bolt on the centers.





Had to enlarge the holes on the side uprights because the TNuts needed a 3/8 hole, rather than the 5/16 for just the bolt.







In all cases there are 2 ea 1/4 inch washers between the bearings and the wood.

Not trying to make this a "Cabinet Making 101" class, but a lot of guys want to do things on their own, and there are damn few wood shop classes in school anymore. I hope they can learn enough to give it a shot on their own.

 

[VanIsle_Greg]

This style of slide works very well. I have a friend who has been building with them for a number of years with great success. Load carrying, cost vs. dedicated expensive drawer slides (for the weight) and ease of deployment all factors.

They work awesome and are very cool to boot!

Nice sketchup diagrams.

 

[Woodsman]

Interesting twist . . . but every method has + and -

This design exchanges the savings in space on the sides (due to lack of ball bearing slides) for wasted space below the drawer (space required by bearings and channel/guide).

In addition, this doesn't allow for full extension of the slide and it does not give you a lock-in or lock-out feature. Maybe those features are not important to some people.

Will there be a bottom of some sort to help maintain tolerances between the side panels and will help ensure smooth operation ?

 

[Retired Tanker]

Interesting twist . . . but every method has + and -

This design exchanges the savings in space on the sides (due to lack of ball bearing slides) for wasted space below the drawer (space required by bearings and channel/guide).

In addition, this doesn't allow for full extension of the slide and it does not give you a lock-in or lock-out feature. Maybe those features are not important to some people.

Will there be a bottom of some sort to help maintain tolerances between the side panels and will help ensure smooth operation ?

You're right, and one does trade off against the other. My intent was to maximize the dead space for all of the parasitic requirements; bearings, mounting hardware, etc. I knew I would need a bottom rail across the front to stabilize the uprights and to raise the drawers over the threshold of the tailgate, so that became my deadspace.

I'm not going to add a full bottom, but there will likely be some additional bracing across the bottoms of the uprights to maintain that tolerance. On the other hand, I'm wondering if trying to maintain too tight of a tolerance and rigidity on a cabinet fastened to the back of a moving / jostling vehicle is really just chasing my tail. Perhaps the tolerance should be more oriented towards accommodating some shifting around while maintaining basic functionality. I'll certainly be able to handle the +/- 1 inch required on either side of the bearings.

And the full extension was a trade off as well. Short of buying pre-made drawer glides, I haven't seen a home-made approach that allow that. And buying them would just not be the same...

And the lock in / lock out feature I'm still working on. Maybe just a barrel latch on the bottom cross brace. Any suggestions?

 

[Woodsman]

And the full extension was a trade off as well. Short of buying pre-made drawer glides, I haven't seen a home-made approach that allow that. And buying them would just not be the same...

And the lock in / lock out feature I'm still working on. Maybe just a barrel latch on the bottom cross brace. Any suggestions?

With the price of the heavy duty locking slides I certainly understand your goal. I would recommend using a regular paddle latch for locking the drawer closed. As for holding it open, you could either have a pin that drops through the top panel and hits a corresponding hole in the top edge of the drawer side or notch a spring loaded tab into the top edge of the drawer side. When you pull the drawer all the way out the spring will push up and keep the drawer from going back in. When ready, you just press it down and shove the drawer in.

As for the lack of a bottom, I would recommend using strips of 1/4" x 2" aluminum bar stock and running that across. Notch it into the side panels and bore and countersink fasteners into the side panels. Locate these strips wherever your floor mounting points are and you can bolt down through them to secure the drawers in the vehicle.

 

[jeepdreamer]

Great job... As I've been working on my own skate bearing drawers and have had to scrap my initial effort for all but the drawers themselves, I am glad to see yours are coming out well.

Btw. .. By retired tanker do you mean tank (m1 Abram etc) or like a truck carrying liquid??

 

[Herbie]

Interesting twist . . . but every method has + and -

This design exchanges the savings in space on the sides (due to lack of ball bearing slides) for wasted space below the drawer (space required by bearings and channel/guide).

Your statement is true, but one interesting aspect of this is that depending on drawer construction, most already have some amount of wasted space below the drawer. Normal drawer box technique is to dado the sides and back/front for the bottom panel. The fastening of the sides to front/back then captures the drawer bottom. You can be more space efficient by just rabbiting the lower edges for the bottom, but then this requires the bottom to be mechanically fixed to the drawer box. Given that most drawer boxes seem to be built with that bottom dead space anyhow, it seems worthwhile to explore using it for part of a roller system.

I will follow this thread with interest...