Up to now, all my woodworking has been with solid wood or plywood. I’m thinking of making some cabinets for the shop and will probably use melamine. I’m not sure how to join the particle board (the melamine will probably be particle board or MDF covered with melamine). I picked up a half box of Confirmat screws at an auction and seem to recall that these are used for this type of construction. Never having used Confirmat screws, I’m not sure how to use them. It’s clear that I’d need to pre-drill holes. What size? How deep? Anything else I should know?
Thanks in advance.
John
Replies
John,
I'm not sure what a confirmat screw is...but when Norm did his cabinets he used special screws and a special drill bit....the screw and bit was fatter at the top...
John,
I'm familiar with them. Designed for KD construction, but they're a great screw for holding together chipboard/particleboard. Better than all others in my experience.
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You'll need to drill two exact sized holes. The first hole is the exact diameter of the shank of the screw - the bit without threads and will probably be exactly 5.00 or 7.00mm, I'm guessing.
The second hole is the root diameter of the screw thread (there's no taper) and will probably be either 3.00 or 5.00mm respectively (2mm less than the shank).
But it's of course hard to tell sizes from half a world away. They may make imperial sized confirmat screws for the US market - so just triple check your dimensions.
I typed in confirmat drilling into google and this was the first link. Lots more there.
Here's a good resource on the 32mm system they're designed for.
You don't need a special stepped drill - just care in your alignment/drilling pattern
Hope that this helps,
eddie
Thenks, Eddie. I searched via Yahoo after I did my post and found your two links and read them. I learned from the first post (in Woodweb) that you need a stepped drill or separate sized drills.
Let me see if I can translate what I learned into specifics. To get the cases square it seems to me that if I'm doing this manually, I'd need to clamp up the box sides, get them flush, and then drill the individual holes ... first with the 5mm bit and then redrill the holes with a 7mm bit. That way they will line up exactly. Since this would be freehand, will it work if the holes are not truly squared up to the cabinet sides?
I won't be using confirmat screws for knockdown purposes. They appear to be very strong. Do I need to add any biscuits or glue to the melamine in addition to the confirmat screws? I'm thinking the biscuits would at least aid in aligning the case sides and may make clamping easier.
Thanks,
John
Hi John,
I'd posted a reply which went AWOL, so I'll repost quickly
As you tighten the screw, you'll clamp the components tighter together. Assuming that the ends were cut square, you'll end up pulling your job square within reasonable limits.
RE: Glue, it's a common way to make the temporary fasteners permanent, so there's no problems there.
Re: the drill holes, I'd drill the 7mm then the 5mm - you'll get a better quality of visible hole edge and the central cone left by the 7mm drill with provide a centring point for the 5mm drill. (Assuming that the drill sizes required are 7 and 5mm.)
Re:biscuits, Dowels are normally used to provide additional hidden strengtheners for the shelves, top/bottom and also to avoid twisting of components as the screws are tightened. THis is probably more due to the fact that these components are drilled on multi-borer so it's no extra time/step to put a dowel drill in one of the drilling heads. Biscuits would work as well if glued in/swollen.
Cheers,
eddie
Eddie,
Many thanks for answering my questions. Just a minor point of clarification. Since I'll be doing this by hand, I'm assuming I need to clamp up the case before drilling. In that case, it would seem to me that I'd be better off using the 5mm drill first, and then using that hole for the 7mm bit. Seems they'd be centered that way. Drilling the 7mm hole first would leave a little wiggle room for the 5mm bit, wouldn't it?
I'll probably try both ways on a sample and see what works best, for me. Thanks again.
John
Hi John,
Yes, the 7mm hole will leave wiggle room, but the cone in the centre of the drill hole will give the 5mm drill hole something to centre on.
The lesser of two evils, I suppose.
The alternative is to try to get the 7mm drill centred on the 5mm hole before drilling and then avoiding chipout/drill wandering/tearout as the 7mm bit centres itself in the hole.
But as you said, nothing beats experience - try on some scrap and see what works.
BTW, as the screw heads may be exposed (eg: putting in a shelf), don't forget to design some sort of concealment where necessary.
Cheers,
eddie
Ditto what eddie said, drill the larger hole first. The small drill centers at the bottom of the large hole much better than the large drill centers on the rim of the small hole. The exception would be if you were drilling the large hole with a piloted counterbore.
If you've got a biscuit jointer then use it to locate the gables (ends) to the base & top rails, one at each edge will be fine then glue & clamp. Drive in particle board screws remove clamps. Locate back, square cabinet, fix back & do the next one. After a bit of experience you probably won't even need to clamp the cabinet up. We make Kitchens for a living doing it this way - it's fast & produces a consistently better cabinet than the nail gunners up the road. Confirmats are pretty much only used by the CNC & CKD brigades & I'd keep them for a job where their extra holding power will be needed.
These guys have what you need, and the prices are reasonable.
http://www.industrialscrews.com/
J.P.
conformat screws are great, many kitchen cabinet manufacturers use them and the strength is incredible
a special drill bit is almost a must, try http://www.leevalley.com
they have the bits and screws
clamp the pieces together, drill, and screw
the right allen key bit in a drill will make driving them really easy
caulking is not a piece of trim
I'm afraid I couldn't find any drill bits on that site made especially for confirmat screws. Mine look like 5mm for the screw, and 7mm for the screw body. Do you have another site that would have this? Up to now, I've been thinking I needed two separate drill bits.
John
Here's one. Bottom of the page. I found it by searching for "step drill".
http://www.quickscrews.com/catalog/pages/bits1.htm
Just use some biscuits for allignment and regular 2 1/4" coarse thread bugle heads.
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