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| How to use direct collets? |
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| kwackers:
If you look at the middle drawbar (as an example) it has a square head. So what you'd do is this, drop the drawbar in, and spin it into the collet by hand (thereby engaging as much thread as possible). Next you'd use two spanners, one on the nut to tighten up whilst holding the top of the drawbar still with a spanner on the square head. When making drawbars, I put two nuts on, one to tighten it and another right at the top which I pin to the bar to hold it stationary ( a small 'tommy' bar can be usefully fitted here instead of the nut). If the cutter is loose in the collet, then I nip up the collet a little first until it's tight enough for me to slide the cutter in and it not to slide back out. (Hope this is what you mean) |
| Bogstandard:
I have never come across collets other than the two threads I mentioned. Have you tried pushing the collets up into the quill with no cutter or draw bar? The rounded end should only just protrude out of the quill, with none of the taper showing. If that isn't happening, there is either something wrong with the MT standard used on the collets or something inside your quill stopping it going all the way in. There should be nothing protruding to get a grip on with anything. A MT taper is classed as self gripping, that means it should lock itself up and grip as soon as it has full contact over it's length (with a cutter in of course), that is how fitting one with a cutter works, as soon as it is pushed in until it can go no further, the cutter should be gripped and and not fall out, and the drawbar can then be tightened up. BTW, MT collets are exact size fit only, that means they can only hold the one size as marked, they cannot reliably be used to grip any other size, so say if it is a 10mm, it cannot be used to hold a 3/8" shank imperial cutter, even though very close. Bogs |
| cidrontmg:
Hello Bogs, kwackers, the collet set is this (the metric one) http://www.rdgtools.co.uk/acatalog/2_MORSE_TAPER_COLLETS.html and like they say, they have 3/8 UNF (=24 tpi) threads. Thatīs no problem, the 3rd drawbar has that thread. I hope I donīt have to make any more drawbars, though. When the collets are pushed in, they protrude some 4.2 mm from the quill, with no cutter. The slits in the collet close at that point. With a cutter tightened, itīs 5 mm. The same with the "extra" collet (3/8 x 16tpi) from another seller. 5 mm is not much to get a grip on, for sure. Thatīs why I wasnīt over-enthusiastic about the oil filter tool-lookalike. All the drawbars have a square 8 mm head. With the mill came a tool that looks like a lathe chuck tool, except thereīs an 8 mm square hole where the lathe tool has a square head. Iīve been thinking about this, and one possibility would be a piece of tube, with a hole the size of the cutter (might need several tubes for various cutter sizes), and a length somewhat more than the cutter. Put the cutter in the tube, with "something" to keep it in there (styrofoam or such) against the business end. Then push the cutter in the still loose collet (with the styrofoam), keep the end of the tube against the collet, and whack the other end of the tube, so the collet closes, and grips in the taper. And then tighten the drawbar. It might even work, if you could follow the thinking... All my cutters except one ballnose are metric. The one exception is a German Guhring with a 1/4" shank... I bought it from Germany, as a 6 mm. Oh well... And as they say, one manīs light tap is someone elseīs almighty blow... :wave: |
| Jonny:
Been using these type of collets for over 11 years plus R8 before hand. Theres no way i would use anything else. Simplified- Each collet has a tapped internal thread, you need a draw bar with that thread to match and screw up. Small Clarke aKA RF25 mill i have three draw bars M10, 3/8 BSW and M12. Larger just buy everything M12. To remove cutter or change collet, slacken approx 1/4 to 1/2 a rev and tap with hammer- out pops the cutter. Simples On the RF 25 i just used to leave the top cover off, its still in the loft 11 years on. I grab the pulley whilst tightening or undoing the draw bar- can change cutters over within 6 secs, so easy. 6 year ago upon buying a Super Lux the first thing i did was make a spindle lock, again simple push button in to vertical splines. 16mm spanner and hammer can change cutters within 8 seconds even quicker on the other mill. No slipping either. |
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