Not a happy bunny!

[Bob Ellis]

I thought I would try making a couple of Graduate magnetic roller ball kits, so I downloaded the relevant PSI instructions, which state that the drill bits needed are 10.5 mm and 12.5 mm, neither of which I had. Foolishly, I splashed out on the relevant Colt drills and used them to drill the blanks, only to discover that both holes were much too big! I then did what I should have done at the start - I measured the diameters of the tubes and found that a 10.0 mm drill was perfect for the long tube and a 15/32" bit was only a little over size for the short tube. An 11.5 mm bit would have been better, but I don't have one.

So, I've just learnt two valuable lessons: (1) don't trust instructions; (2) measure the diameter of the tubes before lashing out on expensive drill bits.

Does anybody know of any kits for which a 10.5 mm and a 12.5 mm drill bit are needed? If not, I have just wasted my money.

 

[silver]

oh dear..

No worries Bob, I can't remember many kits with that size drill. But I'm sure someone on here will correct me in a little while..:wink:

As for kit instructions, never use them and believe them to be written in blood. One you might get the kits mixed up and two they may have changed the tube size.

What you need to do each tome you get a kit out ( that's every one even if you have turned them before) and measure the tubes, then you won't have many problems. Another good idea is measure the fittings by offering the nib and cap up too the tubes just to make sure they are the right ones.

One of these. Drill Gauge | eBay Will help out. Metric and imperial.

I always measure the tubes and also measure the drill in to the gauge just to make sure I have the right ones for the tubes.

You can also use a digital calliper, but the gauge is just simple, just right for me..

 

[Bill Mooney]

I do the same as Eamonn, use drill gauges.

 

[Bob Ellis]

Thanks for the advice. Drill gauge ordered.

 

[Woody]

Drill gauges for me as well they never fail

 

[ni9eofse7en]

I do the same as Eamonn, use drill gauges.

Ditto, both tube and drill bit.

 

[billyb_imp]

Dan's new Alphas need 10.5mm & 12.5mm, although I haven't measured the tubes but like you I have just bought 5 of each (but cheaper ones from UK Drills) I had better measure the tubes tomorrow

 

[Penpal]

Find then measure really pays off but no drill is a loss in the long run I would be surprised if we all do so many other tasks beside pen turning, especially if as you say they are quality drills. Works for me.

Peter.

 

[woodhacker]

I would have done the same as you and followed the instructions

 

[wm460]

I bought a quality set of both metric and imperial drill sets, worth there weight in gold.

 

[Bob Ellis]

I bought a quality set of both metric and imperial drill sets, worth there weight in gold.

I am gradually trying to acquire a similar set, but I can't afford to buy them all at once. It is good to know that the 10.5 mm and 12.5 mm bits that are useless for the Graduate kits will come in useful when I order some of those lovely Alpha kits.

 

[Penpal]

Love my drills they sure get a work out.

Peter.