Nick,
thanks for the spindle write up. I definitely have to look into that.
I like how you do the quote thing. It took me awhile, but I think I finally figured that quote thing out, so here goes.
I made a simple pin wrench tool to crack the spindle nose cap open. I'm not sure what method yours will be, but that seems like a common way the caps are secured. I didn't have any bearing drivers that worked for reassembly so I turned up a set to include one for the head.
MY lower cap does have holes for a pin wrench. like you I just drilled holes into end of a long bar. I had to take that end cap off to get to the collet set screw.
Yes I can see where that pulley block would be a problem. Glad you've got it right in the sweet spot now. Our mill design diverge here a little as mine has a pulley mounted on a swing arm. I'm hoping that the factory got the parallelism close on this to the spindle pulley as I'm not sure how I would correct it if it's off. I'd probably have to shim the pulley sub plate to align it.
If you run into problems you could always just make a base like mine, it can't ever tilt that way. I have that same pivoting setup on my 2 drill presses. One of them never worked right, so I did add a plate and 2 holes like I did for the mill. Works great there as well.
Now admittedly I made a gaffe in the design of this cover. It sits too low to actually remove a belt off the top of the pulley without having to take the bolts out and lifting the cover up. (Whoops) Belt changes will still work fine but in the rare occasions that a belt needs to be replaced the whole cover comes off. With you mentioning running single belt I see that I'm probably not going to be able to do that.
I find that I often just change the collet without changing speeds, so you would be good for those changes. When I do change speeds, it seems like every time I have to take at least one belt off to change the one on top. Same thing on the drill presses, always taking one belt off. I find that I need plenty of space for my hands to take the belt off. Could you just make a riser and weld that onto base of your new cover?
By the way, your welds are MUCH nicer than mine! Wish I could do that as nice.
At some point if I decide to make a spindle brake/ lock I've also got a good solid structure to mount it too, and would likely locate it on top of the cover.
I thought I was going to want a brake/lock as well after all the time on Bridgeports with them. Never had a need for a lock on this mill - it is very easy just to hold the spindle pulley with one hand while loosening / tightening the drawbar. Occasionally I do miss the brake, but it is rare. Somewhere I have a design squirreled away where a guy put a pad underneath the spindle pulley with a side mounted lever. It looked slick and is also on m,y someday list of things to do.
And speaking of future things to do, I have only rarely ever wanted a quill DRO in my 30 + machine years (either on mill or lathe tailstock). I have lots of images I have saved of how others did their DRO brackets for the quill, but yours look very nice. Interested to see how that finishes up.
Few times it happened that I needed real depth control with the quill I just rigged an indicator. Mostly when I need an exact depth on the mill I lock the quill and use the knee screw. My mill actually came with a really bad home made quill indicator holder, one that limited the quill travel to less than 1". First thing I threw away.
I suppose if you wanted to avoid the dovetail cutter you could make a fixture to hold the part at your given angle to mill the bevels with a straight end mill.
I have a 3 way tilting 5" vise, so using the bottom of a cutter was the plan for the dovetails on the side of the sliding plate. The dovetails on the bottom and top blocks I would use the home made or bought cutter.
The little steel block above sitting on the prototype was just used to stop the part from tipping over during the photos. It is actually one of a set of 4 (exactly 1, 2, 3 and 4" long) that I made years ago for Bridgeports and fits this machine - I use them to lock the spindle down when milling so quill can't move.
Could you please explain how these work? Do they sit around the limit screw on the head?
I lower the quill to where I want it, then put the blocks on top of the quill travel blocks, raise the quill back up trapping the blocks, then lightly tightened to stop against bottom of the quill travel block. Maybe these photos will explain it better than I can with words. Here is the 2" block installed
Here is the 2 and 1" blocks installed
Blocks are simply 1.5 dia cold rolled steel with a .530 wide slot milled thru them.
When using end mills I almost exclusively use end mill holders over collets. The end mill set screw chamfer is down against the side of the set screw as well when tightened. I have seen way too many things ruined over the years due to end mill slippage within collets or quill slippage when it isn't rigidly locked (folks think the quill lock will hold it in place) that I just avoid that possibility whenever I can. Even with the end mill holders I also lock the quill with the stop blocks. I always use the knee screw for final sizing. Only time I use a collet with an end mill is when I am trying to maintain an exact diameter or not cutting accurately on the bottom.
To hold size on a part with the Bridgeports (and works well in my 8 x 30) I always locked the quill at top to start, and I usually started with 1" parallels under part in the vise. All of my milling parallels are exactly on fractional inch size, and in .125 increments. Once you got the size you were looking for on the part, I set the dial on the knee to that actual number i just measured. After that you can mill blocks all day long and know exactly where you are by the knee dial without using micrometers every 2 minutes. Reason for the exact 1, 2, 3 and 4" stop blocks was so I did not have to reset the knee dial when I needed more quill travel - I was still accurate with the knee dial when the quill moved down 2 inches. Saved many hours every week with that method. Still needed mics, but not every 2 minutes.
I use indexable cutters as much as possible to keep my end mill costs down. My favorite ones are the 1" negative rake series (like the Valenite mini-mill 45° chamfer one in photo above). The negative ones always want to push back up into the quill (which can only make the part bigger than intended if that happens), so I will use these with collets. When I use the positive indexable cutters they want to pull down so they always go into the end mill holders. My big flycutter for finishing cuts bolts on an arbor so that can't pull down either. I am probably overly anal about that, but then again I have rarely wrecked a block due to being too small.
Ted
) and shortened mine up before final reassembly. The actuation was dialed in so that the spindle lock is fully loose at 12:00 and fully tightened by 7:00. The spreader spring had to be replaced in doing this but it seems like it works just fine. 
