In Line Drills – What are they used for

[Graham WhartonParticipant @grahamwharton]

Always wondered what in-line drills are used for.

In this example, would you have 6 pieces setup on the table and drill all 6 at once, or would you have a number of operators working on their own pieces, or 6 different drill bits and move your piece along the table as you go?

Thanks

Graham

[Graham WhartonParticipant @grahamwharton]

[martin perman 1Participant @martinperman1]

Graham,

In my experience they would be used for drilling, some times tapping, various holes in a product by moving from fixture to fixture.

Martin P

[JasonBModerator @jasonb]

Ouite often you will have a different drill bit in each so from left to right you may start with a spotting or ctr drill, then next along will be pilot drill, then finished size, counterbore or counter sink next and so on.

Table would have various stops, jigs vices, etc so the part can be held as it is moved along the table

[Alan DonovanParticipant @alandonovan54394]

You would have (up to) 6 different drill bits.

For example;

A componet may have a particular hole feature that is drilled through, threaded and have two additional counterbores. In this instance four of the six pillars would be set up as such.

Pillar 1 – Drill through

Pillar 2 – Deepest counterbore

Pillar 3 – Shallowest couterbore.

Pillar 4 – A tap to thread the hole via a self reversing tapping attachment mounted in the drilling machine.

A single operator would have the componet in a 'jig' and move it to each pillar 1-4 sequentially to complete that operation. On completion, the componet is removed from the jig, a new undrilled componet clamped in the jig and you drill the new componet as before. Before CNC this was how 'mass production' drilling operations were performed.

I hope this helps

Alan.

[John Stevenson 1Participant @johnstevenson1]

Posted by JasonB on 04/03/2015 13:09:10:

Ouite often you will have a different drill bit in each so from left to right you may start with a spotting or ctr drill, then next along will be pilot drill, then finished size, counterbore or counter sink next and so on.

Table would have various stops, jigs vices, etc so the part can be held as it is moved along the table

.

Obviously Jason has never used one as you move right to left

But the answers are correct.

I have a twin spindle drill here, RH is for normal drilling, LH is driven by a geared motor, single speed of 90 rpm.

This gets used for countersinking and counterboring as most drill won't go low enough to get a good finish on these two operations

[Graham WhartonParticipant @grahamwharton]

Thanks all. thats cleared it up. My original thoughts of hiring 6 thin people and getting them all on station at the same time seems like such a silly thought now!

Graham

[Chris GunnParticipant @chrisgunn36534]

I spent many happy hours operating a 6 spindle Alfred Herbert version of these during my apprentiship, the one I remember had 4 high speed spindles, and 2 slower reversing tapping/reaming spindles. Some of the spindles had power feed if I remember right. Later in life I bought a 6 spindle AH for next to nothing, still in war finish, when I started in business, and it was in use until I retired in 2004, so did at least 60 years service. It was the favourite drill as long parts could be drilled with ease, and it doubled as a marking out table and long surface plate. It was bought from me by someone just starting out, so may still be working somewhere.

Chris Gunn

[Jesse Hancock 1Participant @jessehancock1]

Yes there were one or two in the machine shop at the place where I started work (earning my £3.0.0 per week). They also had numerous multi headed drills, four per head set out to drill stator end castings all at once. I think the drills were all the same diameter but don't hold me to it. You could see the spindles all turning together.

I used to look at the operators faces, Woodbines or similar hanging on lips and all looking totally bored with what they were doing. It was a bit like looking at cows chewing the cud. The racket in there was terrific from the boring machines screeching, the clang of castings, the whirring of the motors driving the machines and the general hubbub background noises.

 

Edited By Jesse Hancock 1 on 04/03/2015 15:42:55

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