- Joined
- Aug 26, 2020
- Messages
- 12
Hi all,
I have what's essentially a Sherline 5400 mill with a 15" column (I say essentially only since it started off as a vertical lathe column to which I added a base). For those who saw my previous post, I'm back to using the regular column (and I actually damaged the previous column quite badly, so I bought a new one very recently). Additionally, I only just got the headstock; I was previously sharing between the lathe and mill. So while I've been using the mill (and probably abusing it, I'm new to this) for maybe 6 months, most of the important bits are pretty new.
Since first getting the mill, I always felt that it wasn't as rigid as it it should be, only being capable of a 20 or 30 thou DOC and maybe 50 thou stepover with a snail's pace feed rate or else producing terrible vibration and screeching. For a long time, I wasn't sure if that was normal or not - this is my first experience with a mill, so I don't have much to compare to. The main source of doubt was the Sherline insert fly cutter, which would take 50 - 75 thou DOC on an inch-wide part all day without barely a complaint. So for the most part, I was assuming I didn't have the skill level to reach the mill's potential.
I bought a Beall ER32 collet chuck when I got the mill based on all the recommendations I've seen, and have essentially always used it. Well, about a week ago, I used a Sherline end mill holder instead of the Beall collet chuck since I had a cramped setup and the chuck would have run in to a clamp. I was shocked at how much smoother things ran with the end mill holder. I could take cuts there were simultaneously far deeper, with greater stepover, and faster feed than with the collet chuck. I've been using it with the end mill holder ever since, and its night and day. The mill finally feels exactly as I assumed it should.
Everyone here has spoken very highly of the Beall collet chuck, and I haven't been able to find any reports of issues like mine, so I assume I'm doing something wrong (or have damaged the chuck somehow).
Some context:
Next, I measured the various runouts. I'm still new at this, so I wouldn't be totally surprised if my values were off, but I think I'm fairly consistent, so the trends should be useful. (I know about cosine error, but I still find it tricky to get the tip in just the right position and orientation). I have a Mitutoyo half-thou DTI, so the tenths I report are estimates.
I'm seeing about 3 tenths in both the spindle taper and the face (is that what it's called? the flat part, that the threads pull the chuck against)
I see about 1-1.5 thou in the ID of the end mill holder and the collet chuck's taper, and 1.5-2 thou on an actual end mill.
There's quite a bit of variation when I take these measurements, so its hard to make a direct comparison, but I'd hazard the end mill holder has a bit less runout than the collet chuck.
I understand that the 3 tenths in the spindle taper/face is within specification, but the rest seems quite high. That being said, were runout my issue, I would have expected greater variation between the end mill holder and the collet chuck.
One final observation - when cleaning the collet chuck, I found these scratches in the taper. I assume they're caused by tightening the nut with the collet not properly seated (not that I can recall doing that).
So, does all this indicate any particular issue?
Is it worth trying a better quality nut, or even a whole new collet chuck?
Thanks in advance,
Elliot
I have what's essentially a Sherline 5400 mill with a 15" column (I say essentially only since it started off as a vertical lathe column to which I added a base). For those who saw my previous post, I'm back to using the regular column (and I actually damaged the previous column quite badly, so I bought a new one very recently). Additionally, I only just got the headstock; I was previously sharing between the lathe and mill. So while I've been using the mill (and probably abusing it, I'm new to this) for maybe 6 months, most of the important bits are pretty new.
Since first getting the mill, I always felt that it wasn't as rigid as it it should be, only being capable of a 20 or 30 thou DOC and maybe 50 thou stepover with a snail's pace feed rate or else producing terrible vibration and screeching. For a long time, I wasn't sure if that was normal or not - this is my first experience with a mill, so I don't have much to compare to. The main source of doubt was the Sherline insert fly cutter, which would take 50 - 75 thou DOC on an inch-wide part all day without barely a complaint. So for the most part, I was assuming I didn't have the skill level to reach the mill's potential.
I bought a Beall ER32 collet chuck when I got the mill based on all the recommendations I've seen, and have essentially always used it. Well, about a week ago, I used a Sherline end mill holder instead of the Beall collet chuck since I had a cramped setup and the chuck would have run in to a clamp. I was shocked at how much smoother things ran with the end mill holder. I could take cuts there were simultaneously far deeper, with greater stepover, and faster feed than with the collet chuck. I've been using it with the end mill holder ever since, and its night and day. The mill finally feels exactly as I assumed it should.
Everyone here has spoken very highly of the Beall collet chuck, and I haven't been able to find any reports of issues like mine, so I assume I'm doing something wrong (or have damaged the chuck somehow).
Some context:
- I almost always work with 6061 aluminum.
- In the past, my two main end mills were the Sherline 3/8th shank double-ended end mills (usually the 3/8th cutter width) and a 3/8th roughing end mill from LMS. Lately, I've been using a 3/8th high helix end mill from McMaster-Carr instead of the Sherline end mill.
- I almost always use Nikx Stikx, applied to the end mill, and periodically cleaned off and reapplied to remove stuck chips.
- I use convention cuts, except for an occasional 1 or 2 thou finishing climb cut
- When I ordered the Beall chuck, I did not say it was for a Sherline machine (I must have missed this suggestion the first time around, and saw it when looking for posts describing my issue).
- I started out using the Beall collets, but have since switched to Techniks (which I haven't also been using in the lathe), and did not see a large improvement.
- I'm still using the stock Beall nut. I was considering getting a better one for an incremental improvement, but am now convinced I'm seeing greater issues at play.
Next, I measured the various runouts. I'm still new at this, so I wouldn't be totally surprised if my values were off, but I think I'm fairly consistent, so the trends should be useful. (I know about cosine error, but I still find it tricky to get the tip in just the right position and orientation). I have a Mitutoyo half-thou DTI, so the tenths I report are estimates.
I'm seeing about 3 tenths in both the spindle taper and the face (is that what it's called? the flat part, that the threads pull the chuck against)
I see about 1-1.5 thou in the ID of the end mill holder and the collet chuck's taper, and 1.5-2 thou on an actual end mill.
There's quite a bit of variation when I take these measurements, so its hard to make a direct comparison, but I'd hazard the end mill holder has a bit less runout than the collet chuck.
I understand that the 3 tenths in the spindle taper/face is within specification, but the rest seems quite high. That being said, were runout my issue, I would have expected greater variation between the end mill holder and the collet chuck.
One final observation - when cleaning the collet chuck, I found these scratches in the taper. I assume they're caused by tightening the nut with the collet not properly seated (not that I can recall doing that).
So, does all this indicate any particular issue?
Is it worth trying a better quality nut, or even a whole new collet chuck?
Thanks in advance,
Elliot
