Hi Steve,

I think you have a few of options but i don't think masking tape should be one of them as it is just going to be too soft to do the job properly.

Option 1 is to use the 12mm drill to half depth and the 11mm drill the rest of the way and see if you can create a stepped taper that holds the pin sufficiently tightly.

Option 2 is to get hold of an 11.5mm drill to see if this will give sufficient clearance for a tight fit

Option 3 would be to try the step taper thing with the 12mm and 11.5mm drill

Option 4 is the use the 12mm drill and bond the pin in the hole with epoxy, although this will mean you are unlikely to be able to remove it again without damaging the body.

Cheers

Darren

I agree with trying an 11.5mm drill as a first option. I wouldn’t go down the masking tape route personally.

The 11.96 is closest to 15/32nd of an inch if that drill is available?

basically an 11mm hole is too small for the bridge inserts but 12mm is too big!!

A 29/64" drill is very close to 11.5 mm

@peebee

thanks Peebee and Darren

I'm happy to epoxy the pin in...I dont see why I should want to remove it...

bit frustrating as I bought the 11mm bit especially for this job.

I had a quick look, 11.5mm seems a bit scarce...

Be interesting to hear from Mark as it's the wilkinson bridge from the kit and on the course notes it mentions 11mm bit, but also says check....

I think mabe best thing is to drill the holes at 12mm, then use a solution like epoxy, otherwise I cant get on with the next step until I have the holes...

Good news is that thanks to you guys I have done my tests and the holes line up..yay

cheers

Steve

These drill bits on ebay are designed for CNC or line drilling machines and, as such, have a small flat on the shank. However, they can be held successfully in a normal 3 jaw chuck if you are careful how you position them, rotationally, within the jaws. They are brad pointed, have a perimeter spur and are TCT tipped. They drill really very nice clean holes and at about £4 each look to be a bargain.

Be warned, the rather sexy looking bronze coloured large diameter DeWalt drill bits with the reduced diameter centre point can be incredibly grabby if you aren't really careful with rotational and feed speeds. If you want to see a drill bit behave like a massive screw, get hold of some and stop paying attention!!

Cheers

Darren

https://www.ebay.co.uk/itm/11-5mmx10mmx70mm-Carbide-Tipped-Brad-Point-Drill-Bits-for-Line-Boring-Machine-/361651318555

@darrenking

Thanks Darren, appreciate you looking...

I'll get on the case and see how quickly I can get one...

cheers

Steve

Looks to me like they are meant to fit in a 12mm hole...

I just did a test and our Wilkinson bridge posts are still fitting perfectly tight into a 12mm hole

Maybe there is some 'play' in your drill and the hole is coming out wider or maybe the workpiece is wobbling as you drill - that can have the same effect.

If they are a bit loose I would use a little epoxy to glue them but this would be last resort...

More money, but in the UK and in stock!

https://routertooling.co.uk/11-5mm-dia-lip-spur-x-70-r

I came across the same exact dilemna. I ended using the 11mm and drilled it normal for the posts. I came back on on reverse moved it about a bit just to be able to slightly widen it.

Good point Mark,

What brand of 12mm drill have you got Steve, not all tooling is created equal!

Those TCT lip and spur drills are also available in 12mm and the hole will be spot on, guaranteed. Just make sure you get the RH rotation version or you will be making a lot of smoke and the hole diameter tolerance may slip a little! 🤣 🤣 🤣 

Darren

@markbailey

fair point but I used my pillar drill, seemed ok...

I will do another test, by hand as well...although I dont really want to drill the final holes by hand and not get them straight

It's a bosch brad point drill bit...not part of a cheap set so should be nice and accurate...

@clinton

glad I'm not alone and yes, it's just a tad too tight with the 11m...I'll do a test with your method

cheers

Steve

I have a 12mm brad point drill. It was perfect in my test piece using my pillar drill, but too loose with my hand drill.

@robin

well Robin and Mark you may have the clue then....

I'll double check my pillar drill is not wandering and do another test with a very tightly clamped piece...

Just goes to show how important to have test scrap pieces available..

cheers

Steve

@steveadams

I'll double check my pillar drill is not wandering and do another test with a very tightly clamped piece...

I solved it by starting the hole with the brad point drill to get an accurate location. Then I put a short 12mm router bit into my drill chuck and plunged the holes with that. With the router bit being short, it didn't wobble. I would have plunged it with my router if I wasn't working with just battery power.

@robin just a quick mention that even router cutters described as being ‘plunge cut’ really don’t like being used as drills ie a completely vertical plunge. You will reduce wear, and therefore extend tool life massively, if you ‘ramp’ your plunge cuts ie make sure that you are moving forward a little as you plunge. If you do have by to use router cutters as drills then always pilot the hole by as greater degree as is possible so the router cutter is pretty much just acting as a reamer.

Cheers

Darren

@darrenking

router cutters described as being ‘plunge cut’ really don’t like being used as drills ie a completely vertical plunge

A good point there Darren, I didn't know that.