M-head blues...

[hustlebird]

Well, I've slowly been making my bridgeport feel more at home in my shop. I changed the felt wiper, and have finally got most of the grease out. I ordered a new drawbar because the current one is a homebrew concoction that made me a bit nervous. It arrived (along with my MT2 collets), and I decided it was time to swap them out.

Except I got horrible runout with them (10+ thou), and I was pushing them all the way into the spindle... So I went back to the MT2-ER32 tool holder, at least I put the new drawbar in right? WRONG, it had been bored out to 7/16-20, presumably to fit the homemade drawbar... Ok, so I put the old drawbar back in, and mounted the ER32 holder, and I was still getting 10+ thou of runout. Weird, I messed with it, and at one point, I noticed there was like a 1/16" of play with the spindle when the drawbar wasn't pulling the tool up into the spindle.

So I hit the forums, trying to figure out what was going on. Was the spindle completely shot? Until I ran across this thread which mentioned the size difference between MT2 and BS7. So I just pulled the toolholder back out, and measured, very imprecisely because of the bell end, but easily hit that .720 mark. So, I think I have a BS7 head... I just ordered a flycutter and slit saw arbors too.

So, does anyone have a lede on some BS7 tooling? I've ordered the cheapest collet I could find on Amazon, it'll be here wednesday to validate if I'm right about this. I plan to order the ER32 holder. I'd like a JT33 arbor for my chuck. Blanks would be great, I can make my own tooling from there. Perhaps its time to order that taper attachment...

Previous owner gave me a good bit of MT2 tooling too, I don't know how he got it clocked in like he had (within 1 thou). I guess he never swapped tooling since his drawbar wasn't threaded for it. Hopefully the spindle isn't wrecked from the years of MT2 use.

One other note, does anyone have a mirror for this link? I'm getting 404 errors now. Sounds like it would've been useful! shiseiji looks to be active. Thanks for any feedback!

 

[hustlebird]

And just like that, I think I found the source of all my problems. I only had this roughing end mill, but instantly cut like butter through this aluminum at depths i struggled with an MT2 taper. Does this fitment look right to everyone?

Now to start tooling a second time

 

[jwmelvin]

Nice to get it sorted out, though a bummer to have to change a bunch of stuff.

 

[hustlebird]

Well, I thought I had it figured out, but I've been dealing chasing some crazy runout. I'm picking up a pretty consister 15 thousandths of variance, no matter what tool/collet I put in there. with a bit of careful tapping and waaay overtightening of the draw bar its usable, but not consistently, and not in a way that I'm happy about.

My first thought is the drawbar. I ordered an MT2 drawbar from h&w repair, and by their numbers, its 1-1/8" shorter than a BS7 drawbar. I'm not getting full thread engagement, but I don't see that as fixing it? Even with the draw bar removed I'm catching the runout though.

I've snapped some pictures inside the spindle, does this look right to you? I'm sorry for the quality, tough to photograph inside there. There seems to be maybe some sort of insert inside?

My neighbor is bringing over a borescope this weekend so hopefully that might capture some better / more clear insight. Appreciate any help, this has been quite frustrating.