7mm or 6,9 mm, for slimline pens ....( drilling)

[LaurentDH]

Hallo hallo

who has experience not to drill the wood blanks of the slimline pens 7 mm but with 6.9 mm
Here in Flanders , there are many who do that and recommend
The copper tubes are 6.8
so a whole of 6.9 could be better closes as possible better ???
less glue .. ??? - Idea , comments, your opinion ???
second question: who is using what glue to secure tubes ??? curious
best regard
Laurent

 

[randyrls]

Laurent; I use a letter "I" bit or .2720" or within a thousandths of an inch of 6.9mm. Sounds good to me, but I always drill, then test fit to make sure the tube will fit.

Your results may vary. I normally use thick CA (cyanoacrylate) , but if the blank is brittle like Corian, I drill larger and use polyurethane glue (foaming glue) to allow some expansion room for the fittings and prevent cracking the blank when pressing in fittings.

Others use Epoxy or Polyurethane glue.

 

[tomtedesco]

I use two part epoxy on my tubes.

 

[KenV]

Laurent -- Penturning answers are often "it depends" in my experience.

If I am using lucite (clear plexiglass) or similar transparent materials, I want room to paint the interior of the blank and do not want the brass tube to scratch off the paint (so the glue and brass are visible). I tend to up-size the hole a bit and plan on sanding/polishing the hole before painting.

Straight grain dry wood can be snug.

Woods that have dried with distortion, may move with cutting and drilling and may use a bit larger bit.

Last -- depending on the precision of your setup, runout may cause the bit to drill oversize holes, and one can compensate by using a smaller bit, aiming for that sweet spot of good glue coverage but not too much.

It is my experience that if the glue has very good coverage and bond in the 6-10 mm of tube at the ends of the blank, I never seem to have problems with chips other problems, even with thin slimlines. That is to say, the middle of the blank is pretty trouble free. The massive catch or crack in the wood are the exceptions. I seek good coverage in the middle, but do not get obsessive about it. I have tried them all and with moderate thickness they all can work. Personally I avoid CA where subject to impact or shear, and avoid polyurethane (foaming) glues where there is a lot of gap (the foam is weak).

 

[Edgar]

I generally use medium CA glue, but I do use thick CA when the humidity is really high (very common here on the Gulf Coast of Texas) to give myself a little more working time.

I've never drilled under 7 mm, but I do often use a 9/32" bit (7.144 mm) when I'm working with hard, dry, tight grain woods or material like corian. However, I have noticed that 7 mm is sometimes a little loose when I'm working with soft woods like ERC and some unstabilized spalted woods so I may get myself an I bit or a 6.9 mm bit for those blanks.

Like Ken, I make sure to get good coverage on the ends of the tube & usually don't worry too much about the center part except when using cross cut or diagonally cut blanks. In those cases, I also precoat the drilled hole with thin CA & let it cure for a day or two before gluing in the tube.

 

[Ross]

I drill all my blanks using the bit recommended in the instructions. I have had very few problems, most related to the blank not the glue or tube. I would have some concern about drilling with a smaller bit and not having sufficient room for adequate glue adhesion. I do all my drilling on the lathe. I now use epoxy almost entirely. I have used CA, and still do if facing a deadline, but feel more comfortable with epoxy. I don't use poly on pens because I don't want to deal with the foam. I hope this is helpful. Go make some shavings!

 

[dartman]

Laurent; I use a letter "I" bit or .2720" or within a thousandths of an inch of 6.9mm. Sounds good to me, but I always drill, then test fit to make sure the tube will fit.

Your results may vary. I normally use thick CA (cyanoacrylate) , but if the blank is brittle like Corian, I drill larger and use polyurethane glue (foaming glue) to allow some expansion room for the fittings and prevent cracking the blank when pressing in fittings.

Others use Epoxy or Polyurethane glue.

I also use a letter "I" bit and have had good luck with it.Thick CA for wood and two part epoxy on acyclic.