My great plan is to make 55 kitchen door and drawer pulls and save $200.00 over store bought.
If I drill and tap for #8 – 24 threads onto cherry, do ya think that will be o.k.? I’d like to skip and avoid metal threaded inserts.
Thanks in advance,
Don
Replies
How about drilling for a wood screw instead?
Pete
I have seen a screw designed for such an application. It is roughly a #10 truss washer head w/ course threads, almost no taper, and a blunt point. You might want to check McMaster Carr.
Like nazard suggested, I would go with the wood screws specifically made for wood cabinet door handles.
I've seen them at Rockler.
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"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
I did a project recently in white oak where ALL the brass screws were tapped machine screws. It worked great, and was plenty strong; e.g., if you were to tighten the machine screw too much, the head would snap off before the threads stripped out (I verified this during tests on scrap wood).
Lee Valley sells sets with a tap, a clearance bit, and a tap hole bit, but you can just use a standard 8-24 metal tap; I think you get better results using a drill bit a little smaller than that recommended for metal.
There was an article in FWW #126 on this subject; if you have a finewoodworking.com subscription it's at: http://www.taunton.com/finewoodworking/FWNPDF/011126063.pdf From the article:
But I've found you really don't need inserts to make strong joints with machine screws. Metal taps will cut crisp, strong and durable threads in any hardwood. It takes about the same amount of force to strip wood threads as it does to pull a threaded insert out of its hole. And if you tap the wood deeper than a threaded insert requires, the wood joint will be stronger.
All inserts are not created equal. Some thread in (very strong) while others press in (& will pull out). I suppose you want to avoid both kinds. A wood or sheet metal screw which CUTS its own threads will probably hold better than wood tapped for machine threads since clearance designed between tap & screw. A long engagement between screw & wood is also desirable. A safe approach might be to allow enough wood that you could drill for an insert if you strip the wood. It is also advisable to make up a test item which you should attempt to break before you do all that work.
BTW: Those screws are 8-32. If you want 24 TPI, you must go to #10s.
Cadiddlehopper
Helpful, I know, but someone, somewhere, did a study... Machine screws were better. Now if only I can remember where I read it.
Well, there is this: http://www.taunton.com/finewoodworking/SkillsAndTechniques/SkillsAndTechniquesPDF.aspx?id=2489
And: http://groups.google.com/group/rec.woodworking/browse_thread/thread/1a17a8a17c7ac21d/f4c2e854fef0dc8b?lnk=st&q=using+machine+screws+for+wood&rnum=2&hl=en#f4c2e854fef0dc8b
Edited 11/25/2006 9:55 pm ET by EdHarrow
Edited 11/25/2006 9:58 pm ET by EdHarrow
Couldn't read Warner's. The other one is not quite definitive. Personally, I have extensive design experience with threaded fasteners in aerospace applications. Wood fasteners just don't work the same way. If a wood joint sees high stresses, glue is called for, not screws. Screws normally hold things in place but not much more. At least, I don't expect much more. As for those screws that had their heads pulled off: they certainly weren't aerospace grade material!I use many coarse drywall screws in snug drilled holes. The sharp threads hold well, they go in fast, and can even be removed and re-installed several times if you are careful. A deep hole is better. A second choice is sheet metal screws. That is what you get with drawer slides nowadays. I really can't understand why old style wood screws are even made these days.
Like the first poster, I made some wooden pulls. I used pressed in inserts. They didn't hold any better than a wood screw, but my material was scanty. Epoxy solved that one.Cadiddlehopper
I'm just glad we don't have to use cleco's for assembly. On second thought a cleco for clamping wood that didn't require a hole would be pretty handy.------------------------------------
The ultimate result of shielding men from the effects of folly is to fill the world with fools. -- Herbert Spencer (1891)
8-32 is the correct size tap. Drill tap hole slightly deeper than required and run the tap just deep enough for the fastener (if you get too agressive when tapping you might 'bottom out' and either strip the threads or, break the tap Use a starting tap first, then follow with a bottoming tap. Also apply bee's wax to the tap before tapping and afterward clear the tap's threads of gunk and rewax once more.
There has been a bit of testing done on the subject of wood screw vs. machine screw and the machine screw is stronger. An issue of Wooden Boat Magazine recently had an article on this.
You don't need to buy a special tap for this. You can tap the holes yourself by using one of your standard truss head screws (the screws that are normally used for attaching knobs and pulls to cabinets).
All you have to do is taper the end of the screw a bit with a file. It should screw right into the wood if your pilot hole is the correct size. If you want cut threads, you can cut a little V into the point of the screw so it resembles a type 17 (I think!) screw tip. This is the kind of cut that exists in what screw manufacturers call self taping "wood screws."
You should experiment with the size holes you need. It will depend on how hard the wood is.
Hal
http://www.rivercitywoodworks.com
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