Thread: Brass tube reamer

Originally Posted by Stone Monkey

Hi,
I have some pen blanks that are too tight to go on the mandrel without force. The barrel trimmer I have isn't snug enough to fix it. I destroyed a blank last night getting it off of the mandrel and I want to ream the next one out.
I have measured the barrel and it comes out at 6.2mm but a 1/4 inch bolt goes clear through without hitting the obstruction.
As I am sure I am not the first person to have this problem, I have the following questions.
What size of reamer (adjustable or hand) and where to get it? Given that the tubes are brass I don't think I will need anything too hard (expensive), but I would want the cutters to last a long time.
Thanks
Pete

Hmmmnn, pen blanks don't actually go on the mandrel, they ride on the pen mandrel, seated on the correct sized bushings which are inserted into the ends of the brass tubes which are glued inside the pen blanks. To save time, watch all 9 of Davids instructional info-video's, and you will be off and running without drama's. Cheers.
Pen blank preparation for the drill press. « TimberBits Blog

I understand that the blanks go on the brass barrel and then on to the mandrel.
The brass tube inside the blank is not going onto the mandrel. Sorry if I didnt make it clear that I want to ream out the brass barrel encased in a blank.
Thanks

are you certain there is no buildup of glue inside the tubes preventing the mandrel to fit inside ??

I have that problem with some slimline tubes as well. I just use a small round file to slightly enlarge the bore. Its not very accurate or scientific, but works for me.

I have thought about getting an adjustable reamer, but the cost put me off.
They can be had from engineering suppliers. You could check McJings.

Hey Pete,

Some times i get that problem and I have brought a De Burrer, that I use after the barrel Trimmer, (sometimes the barrel trimmer puts an internal burr on the tube)
Then the Bushes or the mandrel wont fit.

HazzaB

I have tried a small round file but I still cant get it on the mandrel. It probably is glue but the barrel trimmer doesn't fit tight enough to clear it out. With hind sight I should block up the barrels with some thing before I slather every thing in glue. You live you learn.
Any way back to the reamers. I havn't been able to find any thing that seems about the right size. Can anyone offer any suggestions.
Thanks

Stone

I have had that problem with 7mm tubes. In fact I had the same problem on Wednesday when I tried to get some slimlines on a mandred for polishing. It is because the mandrel is not properly machined to 7mm. The easy way is to buy another mandrel and with luck it will be okay. I have a few mandrels and one just will not work. I think that is the simple solution. Buy them in Australia to ensure they are 7mm and not US inch measures. Don't use a reamer you will stuff up the tube. Also, some of the tube mills are not exactly 7mm and don't work that well. Its trial and error.

Greg

I am guessing slimlines as they go straight onto the pen mandrels , a 1/4 " reamer is a couple of thousandths too big for what you want, but a 6.3 mm drill is the correct size, not too expensive and should ream your holes out in the brass tubes ,and your fittings will still work do them by hand though as you will have better control and not get seized up in the glued tube . cheers ~ John

in that situation iv got a piece of sand paper 120gr and rolled up into a cylinder and worked that in and out of the tube after a couple of goes you will soon see if the is a bit of glue hiding in there
word of warning dont go over board or you will have an over size tube
then you will have to glue in your componats on assembly
my 2 cents worth
cheers Tony

Originally Posted by Stone Monkey

I have tried a small round file but I still cant get it on the mandrel. It probably is glue but the barrel trimmer doesn't fit tight enough to clear it out. With hind sight I should block up the barrels with some thing before I slather every thing in glue. You live you learn.
Any way back to the reamers. I havn't been able to find any thing that seems about the right size. Can anyone offer any suggestions.
Thanks

I have read Kip Christiensen (sp?) suggests in his book cutting a 1-2 cm slice of raw potato and pushing each end of the tube through the slice to stop glue.

Haven't tried this and have not yet had a problem with glue inside the tubes. But I think it would be worth trying, seems a pretty cheap solution if it works.


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Originally Posted by gawdelpus

I am guessing slimlines as they go straight onto the pen mandrels , a 1/4 " reamer is a couple of thousandths too big for what you want, but a 6.3 mm drill is the correct size, not too expensive and should ream your holes out in the brass tubes ,and your fittings will still work do them by hand though as you will have better control and not get seized up in the glued tube . cheers ~ John

This is what I was going to say. To stop the drill jamming in the tube I spray WD40 onto the bit. I also use mine in a cordless drill. Flatten the end off so that it is not mixed up with other drill bits.
Kryn

As John said, an A mandrel is not 7mm, it is a "nominal 1/4" in fact just a tad under.

One of the best set of drills in the pen making arsenal is a set of letter drills.

I bought mine at a Model Engineering exhibition, letter and number drills come in handy for a range of tasks and are much more closely spaced than a standard metric or Imeprial drill set.

Number & Letter Drill Sizes With Metric Alternatives

This is the type of 115 drills Letter/Number/Imperial drill set I am talking about, although mine came in a metal case and is perhaps a slightly better quality

115 PC TITANIUM COATED NUMBER LETTER DRILL BIT SET KIT | eBay

HSS DRILL SET 115 pcs - IMPERIAL - NUMBERS - LETTERS FANTASTIC RANGE | eBay

Thanks heaps for all the replies. I am sure one of them will do the trick. I will start off with a 6.3mm drill bit.
Pete

[QUOTE=Ray153;1516703]I have read Kip Christiensen (sp?) suggests in his book cutting a 1-2 cm slice of raw potato and pushing each end of the tube through the slice to stop glue.

Haven't tried this and have not yet had a problem with glue inside the tubes. But I think it would be worth trying, seems a pretty cheap solution if it works.

I was getting glue in the tubes and started putting a piece of paper towel in one end. Then packing it in with a round file. Now I use plumbers putty instead of the pt.