How tight does the hole for a dowel need to be? I have drilled a few test holes with a 3/8’s forstner bit for a 3/8’s fluted dowel. the dowel drops right in with no resistance. I tried a 3/8’s twist drill bit and the fit was marginally tighter.
I also experimented with an 11/32nd’s twist bit but I had to pound the dowel in and this flattened out all the flutes.
Is there a specific bit or special bit I should be using or do I need to be so picky?
Thanks and Cheers.
Rundle
Replies
Rundle,
Though dowels do expand slightly when glue is applied, the dowels should be tighter than yours are. When I use dowels, I have to press them in and they are difficult to extract by hand. Sometimes I need to use pliers. I suspect that the type of wood you are drilling may have something to do with this, as well as the quality of the dowels you are using.
I've never used a forstner bit to drill for dowels. I usually use a twist bit. By the way, the DowelMax jig comes with a 9.7mm twist drill bit (3/8" = 9.5249999999mm). I drill the holes with as fast a feed rate (as fast as comfortable) using a corded drill at top speed (habit learned from Kreg). Sometimes I need to clear the chips once or twice. If you aren't inadvertently elongating your holes with your drilling technique, I'd try some different dowels. Stick a caliper on your dowels and see what they actually measure.
In my opinion, the hole should be sized such that the dowel needs to be tapped in, not pounded. Some allowance may need to be given to the species of the material versus the species of the dowel, as well.
Oh, and never trust what the package says about the dimension of the pre-made dowels. ;-)
I't check to see how tight a 3/8" twist bit fits into the holes. If it is reasonably accurate it is the dowels. I've found that smooth dowels vary in size and I ended up taking a doweling jig to the store to find some that were the right size and didn't slide right through.
I tend to think it may be a case of winter and dry air drying out the fluted dowels.
I use exclusively Wolfcraft dowels and the pointed wood bit that they sell as a dowelling bit. As others have said the dowels need to be tapped in and may need plier to remove.
Are your dowels branded? have you tried a brad point wood bit? It may be that your bit is is running out a little and widening the hole.
Your drill probably has too much runout, especially with a Forstner installed. Runout=wallowed out hole.
Get a good set of brad point bits and see if that helps.
If the brad point bit doesn't help, you might try another twist bit. Both a numbered bit or lettered will give smaller incremental sizes than the typical 1/64 jump.
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