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Deckel FP2 n00b questions

sigurasg

Aluminum
Joined
May 4, 2018
Hey y'all,

as a first milling project, I'm making some T-slot nuts for my 1967 Deckel FP2. I'm making these from 4140HT, which is probably a sub-optimal choice for a starter project, but I'm using it as it's what I had. I'm just using the vertical spindle for now.

I squared the stock with a ~1 3/4" HSS shell mill I got with my mill in a dedicated holder, and I used the same cutter to cut the shoulders, no problem. I feel the finish from facing is sub-optimal, so I think I'll need to measure and adjust the end play on the spindle when I go in to re-grease it. I'll have to scare up a tenths indicator first, though.

When side-milling the shoulders, there seemed to be a fair amount of runout in the cutter or the holder. Is that to be expected with HSS shell mills and/or holders, or should I be expecting better?

To square up the ends of the pieces I side-milled (with the Y ram) with a 3-flute 3/8" bright carbide endmill. Initially I fed too slow (1000RPM, 1IPM, or 3tenths/tooth), and by dropping the speed and increasing the feed everything sounded and looked much happier.

When test fitting the nuts, I found they jutted above the table surface a little, so dropped them back into the vise and proceeded to face off some of the excess with the 3/8" carbide mill. I milled the nuts in pairs (hehe), but when comparing the lots, I found their heights to be inconsistent. Eventually I noticed that one of the nuts had a ridge on it, and it dawned on me that the cutter was retreating into the U2 collet. I put a little more gronk on the drawbar and did another pass, and everything came out peachy.

However, I wonder how much gronk (torque) is appropriate on the drawbar?

Also, to tighten or loosen the drawbar, I've been dropping the mill into low gear having the gear train resist me as I give it a yank.
Is this how it's done(TM), or am I going to wreck something?


Siggi
 
However, I wonder how much gronk (torque) is appropriate on the drawbar?

You should have a wrench that's about 250mm/10 inches long and give it a solid tug with your arm and shoulder. Don't throw your entire body weight into it!

Also, to tighten or loosen the drawbar, I've been dropping the mill into low gear having the gear train resist me as I give it a yank.
Is this how it's done(TM), or am I going to wreck something?

That's also what I typically do as well, it works fine, everyone I know does the same.

Important: I realize that it is not relevant to collets, but do not forget to use drive rings on any setup where there is substantial torque and there are drive slots available. Also preload these in the direction that the cutting forces tend to turn them. That way if your drawbar is not tight enough, it won't wreck the internal taper.
 
.... Eventually I noticed that one of the nuts had a ridge on it, and it dawned on me that the cutter was retreating into the U2 collet. ...

These collets seem to like that....I have had it happen three times since my first euromill, everytime with these 355E (U2) collets.
I remember each of these times....(in my cases, due to the cutter geometry, cutter decided to start coming out of the collet, which is also why I remember each case...:) ). It gets much worse with larger cutter diameters.

SK40 collets seem to behave. I would assume 355E would be much better when new, in a new adapter (I've only used old ones), but, still, weren't designed for high cutting forces.

BR,
Thanos
 
I remember each of these times....(in my cases, due to the cutter geometry, cutter decided to start coming out of the collet, which is also why I remember each case...:) ). It gets much worse with larger cutter diameters.

Yeah, my little Taig CNC mill uses ER16 collets, and I've had a 3/8" endmill pull out gradually during aggressive[*] milling. Thankfully I copped on before it pulled all the way out and made a HSS projectile...

SK40 collets seem to behave. I would assume 355E would be much better when new, in a new adapter (I've only used old ones), but, still, weren't designed for high cutting forces.

Maybe I should look into getting some SK40 collets, I need to figure out how I'm wanting to do tool holding.


[*] For a toy/gateway mill, these "aggresive" cuts are a Sunday stroll for the FP2 :).
 
...


Maybe I should look into getting some SK40 collets, I need to figure out how I'm wanting to do tool holding.

....

Already discussed a million times. All solutions have advantages, the more you have the better off you'll be.

BR,
Thanos
 








 
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