Undermount drawer slide question

[Erik Christensen]

The blum tandem undermount slides I am trying for the first time require a very precise notch in the back side of the drawer. Basically you notch out the back side up to the drawer bottom and start flush with the side.

I am using baltic ply for all drawer parts and half blind dovetails. I thought it would better to cut the notch before drawer assembly - use a jig & backer board on the table saw, cut lots of pieces at once with no tearout - simple & fast. So that is what I did after cutting the dovetails.

Problem is the back pinboard has a dovetail piece that: after you take out the dado for the drawer bottom & one for the undermount slide you are left with a tiny orphan piece that in ply just pops off - so now the joint has a big hole - not exactly the kind of craftsmanship I want to show off with undermount slides.

So what do you guys do? cut the notch for the drawer slide after assembly? change the dovetail setup to have a large tail at the bottom to hide the drawer dado? i know this has to work because i see this combo all the time but can't figure out best way to turn our a quality box.

[John Morrison60]

Erik

I have used Blum Tandems for many drawers.
I handle the back corner notch a couple of ways.

1. cut it after the drawers have been completed.
I do this when I dovetail the back corners.

2. cut it before assembling the drawers.
I do this when I use drawer lock mitre joints for the rear corners.

3. leave a big tail to account for the notch.

I do not normally make plywood drawers. I use Maple, Poplar, or Ash for
the drawer box. and I normally use drl joints all around, or a combo of
hb dovetails in front and drl in the back.

Good luck
John

[David DeCristoforo]

It's way easier to cut the notches before you put the drawers together! But you need to accommodate the notch when you lay out the DTs for the backs. There is no point milling any joints below the notch anyway. If you have already milled all of your drawers, finish assembling them and then cut the notches so that the "orphan" piece will already be glued in place.

[Erik Christensen]

no worries but for this project your suggestions are too late - i discovered this bad sequence AFTER drawer stock cut, bottom rabbited, and dovetails cut. this was a learning project - these are just shop cabinets - I'm making sure I know how to use the slides before i move on to something important

for me i'd never use these slides unless i had joinery i wanted to show off - seems dovetails will part of the process - next time i'll cut notches after the boxes are assembled

[Karl Brogger]

I cut them out after the drawer is assembled using a dado head in the tablesaw. Takes two passes to make the 1-1/4" notch which is a pain in the rear. I bought a shaper a couple of years ago specifically for cutting this notch, but I don't have room for it and haven't even plugged it in to see if the machine works, or if it is even a viable solution.

[Rob Sack]

If you don't need a dado for the drawer bottom at the back of the drawer, just cut the back of the drawer straight across at the top of where the drawer bottom dado would have been. The back of the drawer bottom can then be nailed or screwed to the back of the drawer from underneath. I do this for simple, inexpensive drawers for kitchens or bathrooms. For furniture or high end cabinetry, I take the time to carefully cut the notches for the undermount slides, usually before drawer assembly.

[Andy McCormick]

Always cut them after you assemble. Just take a Japanese or some type of fine toothed handsaw and measure 1 1/4 over cut it down until you touch the bottom and pop it out with a chisel. If you do it preassemble you will break the corner off when you clamp the dovetailed drawers together. Andy