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| AdeV:
--- Quote from: bogstandard on November 06, 2009, 10:09:07 AM --- --- Quote ---I'd have thought the Y axis would have needed fewer passes & hence been slightly quicker? --- End quote --- You are quite correct, it would have been slightly quicker, but exactly the same surface area needed to be cut. I have a tendency to cut from right to left. It is just a thing I do, and by doing it the same most of the time, I don't fall into the climb milling trap. I start at the far side and work towards myself. I then don't overtax my brain cell too much, one less thing to worry about. --- End quote --- A perfectly reasonable explanation; I too have issues with a misfiring brain cell... I also have a problem with the Y-axis of my mill vibrating (like a resonance thing, it's a bit wierd) when the saddle is moving backwards towards the column; so I too tend to mill on the X-axis. Except when I forget... |
| NickG:
John, Kept having to mark this thread as unread but have just had a read through and found it very enjoyable. Could do with one of those digital angle gauge thingies. How do you ensure it's parallel to your work piece? Just align the front edge as best you can? Also, when you clamp things in the vice at an angle like you did, do you put any packing underneath or just clamp it tight and take light cuts? I know you didn't take light cuts though :scratch: Cheers, Nick |
| Gerhard Olivier:
Had to go look at the first pic again to understand this one -now it makes sense Nice post thanks Gerhard |
| bogstandard:
Ade, That Y axis problem sounds like a locking up gib strip, it might be, if you have tapered gibs, the gib isn't locked in position by both end screws, allowing it to slide backwards and forwards, so it locks up one way then releases the other. Or it just might be a bit of metal in the gib area or just lack of lubrication. Nick, I wouldn't totally rely on one of those angle gauges, but I just do the squaring up by eye. Aligning one of it's edges with say an edge of the job or machine vice jaw, there is always somewhere square you can eyeball along. But I did mention that they are no use for short jobs as they are, because of the foot shape, it isn't flat, so I stick it on a parallel and use that as the datum foot, as I showed in one or two of the shots. Because the piece I was machining was a big lump, and it was at an angle, I could only get a corner touching the parallels. That told me I was level in the Y axis. Because I was using a 16mm tungsten end mill, my depth on the first cuts were about 6mm deep by about 10 mm wide, only when I get close do I use fine cuts. But you must remember, I have beefy machinery and a big grip on the vice, for normal small mills, those sorts of figures would be way over the top. But a lot of home machinists really do take too long in removing metal. In fact that can cause real problems at times when cutting materials such as bronze, stainless and high carbons. Sometimes just skimming the surface can cause the material to work harden instantly, and no amount of trying will get you thru the hard skin that they produce. That is when brute force comes in. If you are brought up only doing machining at home, you tend to just tickle the metal because you are scared of it, and everyone tells you that you shouldn't take large cuts because it will do damage to your machine. The machine, metal and tooling will soon tell you if you are working it too hard, so you stay just below that threshold. Out in the big world, what I am doing is mini machining, the big boys get the excess stuff off as fast as they can, time is money. That is why you can use one tungsten tip for weeks or months on end, whereas they will get thru them at maybe a dozen or more a day. In fact, at such a rate, some factories have dispensers like Coke machines, put the job number in and it will give you a load of tips for the job. The tip man comes round every so often and fills it up, makes a note of how many have been used, and then bills the company. We are only playing at it. Bogs |
| NickG:
Thanks for the info John. I don't think I've ever had to seriously drill or mill anything on an angle yet! I've probably chosen designs where I don't need to. I always thought I'd definitely have to get a milling machine with a tilting head but that never seems to be the preferred method, suppose you have to fart on re-tramming the mill afterwards - although you don't with your device :lol: I am starting to get a bit more confident, taking heavier cuts, especially now I have a much heavier lathe and milling machine. That's the surprising thing, often a better finish and less noise and vibration is obtained when the cutter is given something to do. I am sometimes falling foul of inaccurate dials / backlash / human error in calculations though. The way I am trying to do things is once I have a clean concentric cut on something, measure it with the digi calipers then work out what needs removing. I'll maybe leave 10thou for finishing cuts and break the bit to be removed up into chunks. On the pistons I am about to show in my flame gulper thread I was taking 40thou roughing cuts which was quite a lot for me - I should probably take more. This is where DRO's definitely come into their own. When I can afford it, I think i may go down that route as it would transform my machines. I know what you mean about the big boys, we have those tool tip dispensing machines at work. I have always been told the bigger the machinery the better. When I asked advice at our club it was to buy machinery as big as your budget and space allows. A big lathe can machine anything a small lathe can but not vice versa! It took me a while to believe this but I definitely believe now! Nick |
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