Drilling holes betwen 2 pieces.

[Spark plug]

I have a job to do that involves drilling a series of different size holes between 2 pieces of bar clamped together, has any one tried this?

I'm just thinking the drill will tend to wander off favouring one side above the other.

 

[MattF]

So you're clamping two pieces flat, and then just drilling through both pieces with the same bit? If so, there's no reason it should wander once you start the hole.

 

[Spark plug]

No I'm clamping 2 pices of bar together and drilling down the join to create 2 pices with half holes in them.

 

[rockweasel]

When you say you're drilling through two pieces, are you drilling through the faces or along the join between the two pieces?

Edit You beat me to the question...

 

[Wozzaaah]

I'm reading this as the two pieces are clamped side-by-side and the holes are drilled along the join?

 

[rockweasel]

I haven't tried it, but I'd imagine that the join would act almost like a pilot hole and guide the drill bit evenly

 

[lshigham]

I've done it, tapped after too. Works fine so long as the bits are clamped properly tight together.

 

[waddycall]

Will the bar be bright or black?if black the drill will probably wander at the start as the join between the two won't produce a flat surface. If you use bright bar you should be able to set it up so it's fairly flat. I reckon it would drill fine once it's established. It's quite common to key parts to ends of shafts by drilling in the join between the shaft and mating part and pressing a pin in.

 

[mr migwire]

get a couple of bit of scrap and try mate,

 

[Spark plug]

Yeah that's what I'm doing drilling down the faces bettwen the two pices of 25mm square. I will be fitting the bars together first with dowels the clamping in the mill vise to 10 holes bettwen 6 - 16mm

 

[rtbcomp]

...It's quite common to key parts to ends of shafts by drilling in the join between the shaft and mating part and pressing a pin in.

Taper-Lock pulleys drill and tap a hole at the interface between the hub and the pulley.

 

[Spark plug]

Yes it's bright but if it dosent fit nice ile mill flat first.

 

[brightspark]

if its set up level and center punched 1st it wont . presume u have a decent pillar drill that wont wander

 

[Kent]

Why not drill each then cut back to a half hole to length? I dont know the sizes but that's my first thought

 

[Spark plug]

if its set up level and center punched 1st it wont . presume u have a decent pillar drill that wont wander

Ile do it on the Bridgeport and centre drill first

Why not drill each then cut back to a half hole to length? I dont know the sizes but that's my first thought

That's what ile do if it Dosent go to plan.

 

[squazy84]

endmill on a milling machine?

 

[MattH]

endmill on a milling machine?

Yep, that would be my advise. Centre cutting endmill. Stub length drill would be the next option.

 

[Spark plug]

I may try An end mill, but as I won't have every size I need I will probably pilot with the end mill then drill to finished size.

 

[Tinbasherdan]

It'll work fine, we used to make pipe clamps exactly this way

 

[tinman123]

if its bms and your doing it on the mill it will work spot on.
they would say to finish with a reamed hole as all drills will slightly wander by nature anyways no matter what your drilling.
its the reamer that gives you the dimension but at this point we are a long way past a jcb fit.