Ok, this probably going to sound silly but how do you all tigthen and loosen the drawbar on the IH mill? What I do is shift the gearhead to Low-1 and with a wrench on top start turn the spindle opposite the way I want and then snap it back the other way. This seems really crude but I have found nothing better. There are no spindle locks (unless I am looking in the wrong places) and without access to belts nothing to really hang on to. I thought I would make a spindle wrench to fit over the splines and I noticed a retrofit spindle lock in Feb/March 2003 Machinist Workshop that is cleaver, but wonder if there was some other more obvious way.

Related to the drawbar, the nut pull off mine and I welded a piece of 3/4 hex on top. I suspect the drawbar will pull in two before the weld gives. Now before you say I was tightening the old drawbar too much (perhaps I was) I have had end mill drop out of collets which has prompted me to start using end mill holders. But carbide tools don't have the flat so back to collets for those.

Oh, BTW: can one expect to be able to have reproducible tool height measurements with R8? E.g. is it reasonable to put an endmill holder in, tighten the drawbar to X ft-lbs, measure from the table to the tip of the end mill, remove the holder, repeat, and come up with the same measurement?

BTW: I am going to give the HF impact wrench power drawbar. Maybe that will help as well?

Thanks.

Wildcat...without a spindle lock....you're doing it properly.

The nut came off your drawbar....well it was probably a poorly made one.....most likely someone machined too deeply and when you tighten you stretch the draw bar....and it finally fatigued to the point that it broke....if you have had end mills drop out of collets......there could several problems.....a collet that is not machined properly.....the mating surface in the spindle that is not machined properly.....

Yes, it is quite reasonable to have consistent measurements.....if you can actually place an end mill within it's holder in a consistent and accurate method.

Ok, was hoping there might be a hidden spindle lock some place. I'll give making a spindle wrench a go.

Re: the drawbar - yes, poorly made :) it appears they took small section of hex stock, drilled the center and then pinned it to the drawbar. The pin ultimately was pull through the small amount of metal under it.

If it makes a difference the tool dropped out the collet while machining... I don't want to give the impression that it was possible to pull the tool out with my hands. The collet was Lyndex and the tool was cheap-o Enco 1/2 or 3/4". It has happened two or three times. The collet was sprayed with an anticorrosion spray (seems like everything around here rusts). Could the oils in the spray provide enough lubrication to allow the end mill to be pull out? I hope that your suggestion about the spindle is not the case... that would be disappointing :(

Wildcat, low gear and wrench is what it takes, and keep a chunk of brass or something to tap the drawbar out. then make sure the size of tool shank and collet are the same, or you have a problem, sometimes if you overload them they will move anyway. tormak has a cool tool set for doing preloading of tools that you might look into, i got one and like it. the set is a bit spendy but worth it if your going to stay with R-8 a while. It may help to keep a can of carb&choke or spray break clean handy to blast off shank and collet, but really not all that necessary, more than likely it was just overloaded, climb milling can pull out tool and conventional can push it and it'll directly relate to tightness of draw bar but you don't want to be over tighening the draw bar either, better off with the setscrew type holder for roughing. Well, time for me to go out and do the wiring i was spose' to do yesterday, cracked rib's hurt for some dern reason, ENJOY GUY's

Here is the spindle wrench (~1.6x9.5x.25) I cut out using 1/4 and 1/8 end mills. A little deburring and filing was needed to square up the sides of the business end of the wrench (and my measurements of the spline were a little too tight) but I am pretty happy with it. Had to turn down the washer under the drawbar a little as well. Wish the fixturing holes were not needed. If someone knows how I could have got away with not having them in the body I sure would like to know how. Unfortunately Mach does not save start and end times to the history but this took about 40 mins of machine time.

http://www.cnczone.com/gallery/data/500/medium/CRW_3831.jpg

oh man thats a spiffy tool.. i wouldnt worrie about the holes.. gives it character.. that and a place to put a string through so you can hang it up!