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Blumotion Undermount Slides Not Fitting Right4/22
First time using these, they're the undermount 563 series. Instructions all over the web says 21mm from cab side to inside edge of the drawer side, 7mm from there a 6mm hole. Do all this and they don't fit. Checked and rechecked my measurements and they are spot on. My math says 21mm and 7mm puts the holes 28mm from the cab sides. the pins on the slides are 30mm from the cab sides. How is this going to work?? Well it doesn't. Have to redrill the holes 2mm over. Any thoughts?
Two things to check:
1. What is your drawer side thickness? (See attached)
2. Take this measurement (If using 563 or 563H):
Cabinet opening - 42mm = should be your inside drawer measurement
It's not as simple as a side mount drawer where you take the opening measurement and subtract an amount and you have your drawer width.
They have a somewhat simple formula that takes into account the drawer side material thickness to calculate the width of the drawer.
The reason for the formula is Blum is looking for the inside of the drawer dimension, not the OD. I've made up an Excel spread sheet with a formula that calculates the width of a drawer depending on the material thicknesses. I use 15mm Baltic Birch plywood for the most part and it varies in thickness like most plywood does between .580" and .605" so I pop that specific number into my spreadsheet after measuring it with a caliper.
If you are using solid wood it's much simpler to use standard thicknesses and just subtract the required amount according to their chart.
Either make or buy their jig to drill the hole in the rear of the drawer. I've made a router jig to get the notch for the back side. The corners aren't square on the notch, I use a 1/4" flush cut bit and I haven't had any issues. If you don't have a notcher you need to use a tablesaw or a router jig to make the notches. Or just have the back side of the drawer undercut so there is nothing hanging down.
Getting set up is the hard part. After you do that the drawers are much easier to use than a side mounted slide. You are only mounting the slide and then a simple lock under the drawer. No aligning a set of slides to each other.
Where C8 is the opening width and C5 is the material thickness. 1.656 is 42mm I believe converted to inches which is part of the Blum formula
I use this program to calculate all my sizes at least the first time to check clearances.
Thank you gentlemen. I understand the calculations to determine the OD based on the material thickness and that is what I did (15mm BB) but if the inside edge is 21mm from the cab side, and the locating hole is 7mm from that edge, doesn't make sense that if you measure from the side of the cabinet to the pin it should be 28 mm? That's where I'm having a problem because every which way I measure the pin is 30mm from the cab side.
Measure the pin off the drawer, not off the cabinet. I'm assuming the hole above the notch.
Take a look at the attached. Looking at only one side of the drawer the inside of the drawers is 21mm from the cabinet side, the pin hole is 7mm, so 28mm from the cab side. When I measure the pin on the slide from the cab side it's 30mm to it's center.
What is the inside opening width of your cabinet?
What is the inside dimension of your drawer?
Everything is measured from these two values. I should ask what is the thickness of your drawer side however it really doesn't matter if it is less than 3/4". Preferably to be 5/8".
Blum makes a jig that works well, its in the back of the catalog.
We don't use Blum but is the product code stamped on it? Wondering if you could have received the wrong product.
With the Blum slides I subtract 5/8" in width and 3/4-7/8" in height they work every time, I use 1/2" material. I use a simple shop made jig and drill the hole exactly where it calls out .Good luck.
I think the runners have enough movement (slop) that they will move 2mm inward from the 30mm you see. I use those measurements and have never had a problem. Have you checked to insure the upward measurement is correct also.
Hope you get it sorted out but the dimensions in the drawing do work for me.
Mystery solved, the slides I received were 563F, the instructions I was following was for the 563H. Inside drawer measurment is 21mm for the H, 24.5mm for the Fs. First time with these slides. glad it was me and not the product. Thanks guys.