Drilling in the mill

[Gone AwayParticipant @goneaway]

I’m truly amazed Jon.

 

I break the torque my (ER) collet (maybe, what – 1/8-turn?); hand unscrew it a further 1/4-1/2 turn; tool/chuck drops out (into my hand). Plug in new tool/chuck; hand tighten; nip up with wrench.

 

Never timed it but it’s sure a lot quicker than typing it and way, way quicker than swapping my R8 end-mill holders for an R8 chuck. It’s why I went the collet route in the first place. No way I’d go back to swapping the R8 for every tool change.

[Lawrie Alush-JaggsParticipant @lawriealush-jaggs50843]

Hi Wolfie

I will though my two bobs worth in.
I first came by a bench drill about twenty five years ago and it was really the only machine tool I owned for about twenty three of those years. It has served me well and continues to do so.
A bit over two years ago I bought a round column Mill/Drill and thought about getting rid of the drill but I couldn’t do it. I am glad I didn’t for several reasons:

1 I can have a job set up in the mill and still drill fairly accurate holes in the drill.
2 I have also drilled wood in my mill but it is a cumbersome excersise and is much better done with the drill. For one thing I have a greater range of speeds available on the drill.
3 Yes you can rotate the mill head through 180deg and drill down to the floor but you mention that you are low on floor space so I think that that is a bit of a red herring. I thought of doing just that myself but realised that to make it possible, the mill would either have to be on wheels so that it can be pulled out or you would havve to find some other way of moving it. Once you try it and find out how cumbersome it is to manouver things behind the mill I think you will not want to do it again. There is also the fact that once you rotate the head to the back of the machine, you have nothing to hold the work. All in all this is a furphy.
A dovetail column allows you to move the head up and down thus keeping the quill as far into the head as possible thereby significantly aiding rigidity.
4 Buy a dovetail column mill rather than a round column. My round column is excellent and I get a great deal of pleasure from it but it has a restrictive work envelope. You have to plan your work very carefully. If you want to set up a peice of work in the vice and have room to use say a 14mm drill in a chuck, then swap to an ER32 collet with a 3mm end mill in it, then a slitting saw you are going to find it difficult. Not impossible but often difficult. On my machine I have 100mm of quill travel to play with which seems a lot until it isn’t.
5 As I found out this evening whilst ruining a peice of cast iron I have been working on on and off for a couple of weeks. Tthe clamping bolts for the head are made out of Swiss cheese. Sure that is just a matter of being aware and putting in HT bolts when you get the thing but it is another reason for getting a dovetail column. What happened? I thought I had tightened everything up nicely and started machining. The work is mounted on a plate affixed to the rotary table which is mounted at ninety deg to the table. I was taking a cut at one end of the job and finding that it was not cutting by the end of the cut. The bottom bolt had stripped and when I took a decent cut, the head just slowly swiveled away from the work.
6 There is one time that I have been glad to have a round column and that was a job where because of the length or the work, I had to swivel the head to one side by about thirty deg, something that would not have been possible on a dovetail column machine.

With all of the above said, I am happy with the round column, it is quite tough and has the oomph to get through all of the stuff I throw at it with aplomb. But if I had my druthers, I’d go for a dovetail with a variable speed motor and XZY DRO.
I would therefore also keep the drill. If you are limited for space, rework your workshop to suit.

 

Lawrie

[JonParticipant @jon]

I fail to see where your coming from and the logic Sid.

Two spanners to find and pick up against one. Undo and remove the collet nut, every time a different collet needed, remove collet from nut and put back replacement in, then of course the reverse not less than 45 secs.

Not to mention the extra loading on the bearings and cutter dropping and thats with Wabeco supplied ER even worse the chinese ones. Should i mention the lost height.

 

R8/MT3/2 looking at collet change and cutter in less than 20 secs with undue loading on bearings.

 

 

Lawrie i still have my round column as a backup 7 1/2 years on. When i used to use it i left a socket and ratchet by the side. Just have to plan your workload height if want to retain centre, thats the key thing.

Must admit i did mill away a few times without tightening much the same effect as when a vice breaks.

Think i flashed over 20″+ by swinging the head round.

The problem with dovetail columns is seemingly never enough tension on the gib strips with around 200kg hanging off, the column dont flex nothing like a Wabeco but theres definate movement putting a cut on. Swings and roundabouts.

 

 

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