cracking

[McBryde]

When I am inserting the parts into my finished blanks I am getting small cracks forming from the pressure outward. Is there anything that can be done to discourage cracking? I am doing slimlines and am using a 7mm bit to drill them. Should I go to the drill bit that is a little larger to discourage this, or will that even help? I'm sure others have had this problem, any solutions would help.

Thanks,

Emerson

 

[Russianwolf]

try chamfering the tubes. Many times when trimming them you'll get a burr that will cause this problem. chamfering removes the burr and should stop the problem.

 

[PenMan1]

On slims, I use a "J" bit and chamfer the tubes. Works like a champ.

 

[Brooks803]

also make sure there is nothing on the inside of the tube like dried CA or epoxy.

 

[McBryde]

What exactly is chamfering?

E

 

[bubbatww]

Emerson,
I was having the same problems...posted the link to my msg..and so far no more cracking!!!
I bought a round chain saw file and I have a reamer...
Things are getting better.
http://www.penturners.org/forum/showthread.php?t=58933

Hope it helps

 

[glen r]

Chamfering

Chamfering is sligthly beveling the inside edge of the tube. If the tube is clean of any CA or epoxy, chamfering ensures that when you are inserting the parts into the tube no part of the tube edge tends to fold in on itself and therefore increase the size of the tube.

 

[Russianwolf]

putting a bevel on the inside of the tube. here is what I use.

http://penturnersproducts.com/index.php?main_page=product_info&cPath=6&products_id=48

 

[McBryde]

I have a chainsaw file, how much are you taking off the inside of the end?

E

 

[Mac]

E are you still working with that extra dry walnut!

 

[emccarthy]

another alternative to a deburring tool is a countersink, which you can put on the end of your drill and carefully(!) drive to accomplish the same thing

 

[randyrls]

When I am inserting the parts into my finished blanks I am getting small cracks forming from the pressure outward. Is there anything that can be done to discourage cracking? I am doing slimlines and am using a 7mm bit to drill them

Emerson; The most common reason for cracking is glue inside the tube. I use an Exacto knife to remove any glue inside the tube. A pen mill will NOT get all the glue out.

Some materials are brittle and don't have any "give" to them. Corian is one such material and will crack if looked at wrong.

If using a material like this, I sometimes use a transfer punch or junk mandrel to "expand" the last 1/4" of so of the tube. A gently sideways twisting motion will enlarge the tube end and the fittings will just slip in. Prepare the blank as normal, and then mix up a little epoxy or use CA thick to glue the fittings in. Put the glue inside the tube, NOT ON THE FITTINGS. Insert the fittings and turn them entirely around to spread the glue.

Note: CA will "outgas" and fog the finish on most platings so if you do this, leave the pen open and out for 2-3 days so the fumes can dissipate.

 

[snyiper]

Just take your chainsaw file and hit the inside edge dont really need to remove any material just knock off any burs from cutting or excell glue

 

[MobilMan]

I must be a cheapskate, I just use my ol pocket knife to clean the ends.

 

[lazyguy]

I use this works great no power tools needed.

 

[McBryde]

Thanks for the help! I am off for spring break this next week, so will be out in the garage tinkering with it more. I will give the chainsaw file a go at it on the next one.

No Mac, haven't used any more of that. I have had bloodwood, wt deer antler, and bocote all crack on me though. I have to get this under control, it is making me crazy!

Nothing like making a blank to completion and then it cracking when you assemble it to ruin a day!

Emerson

 

[KenV]

Locktite is your friend for setting pen components into the tube. Easy, less mess, and when using the purple or red color coded version, the pen can still be disassembled later if needed for refurbishment. (Yup -- some come back after a few years for a refinish or repair).

For sensitve materials like corian, snakewood, ebony I want finger firm push it in without a press and a couple bits of locktite.

 

[wdcav1952]

Emerson,

For chamfering, I use this http://www.midwayusa.com/viewproduct/?productnumber=789334

To clean glue residue out of the tube, I have a selection of sizes of brass gun cleaning brushes to use.

Do you seal the ends of the tubes when gluing? This will keep glue out of the tubes. Dental baseplate wax, silly putty, play doh or the like to seal the ends of the tubes.

 

[ROOKIETURNER]

I just clean out the tub with a piece of threaded rod. Most have a piece or two laying around the shop. It deburs and removes any glue from the tube. Done correctly and it will even bevel the edge just enough for a smooth assembly.

 

[KDM]

You sure it's a 7mm bit? My (limited) experience is that my 7mm holes are a teency bit too bit for the slimline tubes.
I guess if your timber wasn't quite dry, the hole might not bore out to 7mm. Not sure what the effect is called, but when you bore a damp or soft material, the hole can end up smaller than the drill bit!

 

[CHICAGOHAND]

Turners against glue in tubes

I always seal all tubes just like WDCAV192 said. and then depending on the inner diameter I use a long threaded rod to lightly debur the inside of the tube. I have built pens for a couple years now and always hated scraping glue out of the tube. Get some play doh and put enough in on both sides, glue tube in, clean play doh out with an old mandrel rod or appropriate sized piece of metal depending on what you are building, and no more glue in tube. Works wonders and saves time.

 

[thewishman]

I must be a cheapskate, I just use my ol pocket knife to clean the ends.

Fellow cheapskate here. I use my utility knife.

 

[McBryde]

Thanks for all the info guys, will have to try some of these out on the next pen.

E