How perfectly parallel do draw sides need to be?

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Forum topic by Andy382 posted 08-10-2016 04:37 PM 587 views 0 times favorited 7 replies Add to Favorites Watch
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2 posts in 74 days

08-10-2016 04:37 PM

Hi everyone. I’m a novice woodworker, trying to convert my space under the stairs into a cupboard and drawers. I have a space prepared to install a drawer, but I’m concerned that the sides are not quite parallel.

The drawer will be 80cm deep, and the space is 48cm wide at the front. However, the space at the back is 5mm shorter, at 47.5cm. This is a really minor difference, and to the naked eye the sides look perfectly parallel.

If I install the draw runners (75cm heavy duty ball-bearing) should I be ok, or do I need to do something to make the sides 100% parallel?

(in the photo the drawer is going in the space at the bottom – photo is on its side with the top on the left)

Thanks for any help that you can give!


7 replies so far

View ScottM's profile


330 posts in 1566 days

#1 posted 08-10-2016 04:44 PM

I think it will depend on your plans for the drawer fronts. If the sides aren’t parallel then it will show once the front is either laid on top, for an overlay, or has to fit between them for an inset. You’ll have to cut your drawer front to match the “wonkiness” of opening.

View distrbd's profile


2220 posts in 1866 days

#2 posted 08-10-2016 04:47 PM

You should do your very best to make the sides parallel ,or you’ll end up shimming one side or even removing material from the other side to stop the slides from binding.

you could make a spacer (cut from scrap wood) to the exact distance as the width of the drawers and test the space between the runners ,it should give you an idea how parallel it actually is.

-- Ken from Ontario, Canada

View pintodeluxe's profile


4825 posts in 2233 days

#3 posted 08-10-2016 04:50 PM

Make the slides parallel. Build the drawer box to fit, based on the smaller dimension. Only the drawer front needs to fit with consistent reveal (assuming they are inset drawers), and that can be applied at the end.

If you’re building overlay drawers, then it is even less critical.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Andy382's profile


2 posts in 74 days

#4 posted 08-10-2016 04:59 PM

Thanks everyone for the quick responses!


View Loren's profile


8159 posts in 3067 days

#5 posted 08-10-2016 05:16 PM

You can make a pattern using the Joe Frogger
trick… using an undersized piece of cardboard
in the opening, trace an undersized pattern
using a spacer block. Then make a full-sized
pattern from that and you can from that pattern
make a drawer perfectly tapered to fit the

Ball-bearing slides are pretty unforgiving… maybe
1/16” of play for the pair side to side so
you’ll either want to shim out the slides to
make them parallel or do something like
I described above.

View MrRon's profile


3891 posts in 2663 days

#6 posted 08-10-2016 06:03 PM

5 mm is too much to be out-of-parallel; the slides will bind. Determine which side is the most out by checking for square with the front using a combination square. Shim the most out-of-parallel side.

View MadMark's profile


965 posts in 872 days

#7 posted 08-10-2016 09:07 PM

You cannot taper ball slides. It does not work. For best results your play should be no more that 1.5mm. (1/16”)


-- Madmark -

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