Re: Painted Myself Into a Corner Again
Photo bucket wants me to disable my ad-blocker before it will show your photo. ? Not going to do that. ?
You need to use the DI in two places. 1. on the park very near the chuck and 2. on the part very near the end.
Maybe a little plastic faced hammer could be used to adjust the DI reading near the parts end.
On Tue, Jul 25, 2017 at 2:12 PM, acoe@... [7x12minilathe] <7x12minilathe@...> wrote:
?
Thought I was being clever this time and started turning a piece on a long hunk of 2" stock - so I'd have plenty of margin for error.? See photo: ?
Next step is to drill a hole through the center of the turned section, starting from the tailstock end.? Unfortunately, in my cleverness, I didn't account for the length of the chuck and the drill - I either need a longer lathe bed or a shorter set up.
So, the next step now is to cut off the turned section and re-mount it in my chuck.? Which leads to my question.
I've gotten pretty good at centering a piece in my 4-jaw chuck, using DI.? But, in this case, I need to center the counter sunk hole (where the tailstock is currently mounted) and also make sure the axis of the hole I drill will be parallel with the axis of the turned portion (IOW, make the axis of the turned portion parallel to the bed).? The turned down portion is about 2" long, so if it is not aligned parallel with the bed the hole will be off by quite a bit.? Any advice on the most efficient way to achieve this alignment?.
--
Chris Albertson
Redondo Beach, California
|
How does the side mounted ball screw work? ? I'd be worried about the torque trying to turn the milling head.
The design I like better places the screw on center line and almost touching the existing rack.? The head's weight is basically hung off the stationary screw.? The screw does not turn.? A motor is used to rotate the nut.? I think the overall design is simpler.
People are getting better than .001" with this kind of setup.
Searching around I find a photo of this design here.? It lifts from the center of mass.? Disadvantage is you need a full height ceiling but likely a non-issue for most.
Allthat said.? I have a simple DRO mounted to the z-axis and it is accurate to .001 and reads to .0005 if I use the gib lock if there is any depth movement it does the DRO is not detecting it so I amuse not movement over .0005" ?and this is with a stock mill, I'm not done with the CNC conversion.
On Tue, Jul 25, 2017 at 8:01 AM, WAM ajawam2@... [7x12minilathe] <7x12minilathe@...> wrote: I bagged that whole rack-pinion thing for something a bit more robust:
Actually my wife wanted it changed. She used it when we first got it,
said it sucks, and suggested the stepper I did, or something like this:
I can send the 3D model of that if you'd like...Uses off the shelf gears
from Boston Gear. Uses the same CNC Fusion ball screw.
I've been using the stepper/Arduino thing for years and really like it.
I can get accurate depths that hold.
As to the stock mini mill setup, everyone states you should lock the
gibs, or tighten them up. Also you can check your rack-pinion mesh and
shim the rack to make it a bit more tight.
I didn't like any of those suggestions. A rack-pinion is great for a
drill press; not so much for a mill, at least in my opinion...
//
On 7/25/2017 10:12 AM, 'Johannes' johannes@... [7x12minilathe] wrote:
>
> l.JPG?dl=0
>
>
>
> This is the fine-adjuster to LMS 4700 Mill.
>
> Have somebody made a lock for this?
>
>
>
> My adjuster is moving (turning) when I am milling, and before I am doing
> something stupid, I want an advice from you.
>
>
>
> Best regards
>
> Johannes
>
>
>
>
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--
Chris Albertson
Redondo Beach, California
|
Painted Myself Into a Corner Again
Thought I was being clever this time and started turning a piece on a long hunk of 2" stock - so I'd have plenty of margin for error.? See photo: ?
Next step is to drill a hole through the center of the turned section, starting from the tailstock end.? Unfortunately, in my cleverness, I didn't account for the length of the chuck and the drill - I either need a longer lathe bed or a shorter set up.
So, the next step now is to cut off the turned section and re-mount it in my chuck.? Which leads to my question.
I've gotten pretty good at centering a piece in my 4-jaw chuck, using DI.? But, in this case, I need to center the counter sunk hole (where the tailstock is currently mounted) and also make sure the axis of the hole I drill will be parallel with the axis of the turned portion (IOW, make the axis of the turned portion parallel to the bed).? The turned down portion is about 2" long, so if it is not aligned parallel with the bed the hole will be off by quite a bit.? Any advice on the most efficient way to achieve this alignment?.
|
Disregard my comment, I was unaware that the 4700 has a
spindle that moves up and down, unlike the other mini mills where the entire
head moves up and down.
Mike from mikesworkshop has the correct
solution.
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Show quoted text
?
Hello Johannas,
?
I'm not familiar with the 4700 mill, but from the photo of it
on the LMS website, there is a column/gib locking lever on the left hand side of
the column. Locking this down should lock the head from moving. Any movement
from vibration of the fine adjust wheel while milling should not matter, and
will not move the milling head.
?
All unused table and head travel
should be locked down prior to milling.
Michael - California, USA
Micro-Mark MicroLux 7x16
LMS 3990 Hi-Torque Mill with power
feed
?
This is the fine-adjuster to LMS 4700
Mill.
Have somebody made a lock for
this?
My adjuster is moving (turning) when I am
milling, and before I am doing something stupid, I want an advice from
you.
Best regards
Johannes
|
Hi and thanks for response. Here is how the fine adjuster looks inside: https://www.dropbox.com/s/s2tx6cgt0j8wm7s/adjuster.jpg?dl=0 ? My thoughts was to look the axel from underneath, it have most of the steel to make a hole for a screw. But may maybe I can fix the problem from the other side as Mikes workshop suggest. http://mikesworkshop.weebly.com/mill-quill-lock-lever.html ? I will think about all suggestions for some days and I will come back when I have done the job. ? /johannes
|
Hello Johannas,
?
I'm not familiar with the 4700 mill, but from the photo of it
on the LMS website, there is a column/gib locking lever on the left hand side of
the column. Locking this down should lock the head from moving. Any movement
from vibration of the fine adjust wheel while milling should not matter, and
will not move the milling head.
?
All unused table and head travel
should be locked down prior to milling.
Michael - California, USA
Micro-Mark MicroLux 7x16
LMS 3990 Hi-Torque Mill with power
feed
?
This is the fine-adjuster to LMS 4700
Mill.
Have somebody made a lock for
this?
My adjuster is moving (turning) when I am
milling, and before I am doing something stupid, I want an advice from
you.
Best regards
Johannes
|
That's a great idea.
You always have cool stuff for these Sieg things... your site should to be required reading for anyone with any of these mill/lathes...
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Show quoted text
On 7/25/2017 2:18 PM, mikey.cox@... [7x12minilathe] wrote: WAM there is a recessed M8 socket screw bolt that locks quill in position on the other side of the headstock. I have added a lever to mine so I do not need to find the M8 allen key, see:
Mike
|
WAM there is a recessed M8 socket screw bolt that locks quill in position on the other side of the headstock. I have added a lever to mine so I do not need to find the M8 allen key, see:
Mike
|
The GrizHFMinimill group has been dormant for some time. I think most posting has been done here. ---In 7x12minilathe@..., <mark.kimball2@...> wrote <SNIP> I would have just suggested you visit the GrizHFMinimill group but many folks in this group belong to that one, too.? However, it would be the one to get input on how owners have tried to address various parts of the z axis problem.
Mark
|
Does it move when you have the Z axis lock lever on the left side
of the column locked down??? Unless you are really using this in
the "drill press" mode, that should be locked after the cutter
depth is set.
Does the cutter move, or does just the knob move??
On the X-2, the knob will move within the slack zone, and it is
important to take up the slack before unlocking the Z axis.?
However, with the Z axis locked, the tool itself does not move.
I dont like the sloppiness of the X-2, so I work with an
indicator on the Z axis to measure/set depth.
Warren L
On 7/25/2017 10:12 AM, 'Johannes'
johannes@... [7x12minilathe] wrote:
toggle quoted message
Show quoted text
?
?
This is the
fine-adjuster to LMS 4700 Mill.
Have somebody
made a lock for this?
?
My adjuster is
moving (turning) when I am milling, and before I am
doing something stupid, I want an advice from you.
?
Best regards
Johannes
?
|
Johannes,
The Z axis fine-adjustment mechanism is one of the more poorly-designed components of these machines.? It is a sloppy worm drive that engages a sloppy castle nut system which drives a sloppy rack and pinion.? Sloppy cubed = VERY sloppy :).
The end result is the so-called head drop problem where the head will suddenly drop during a milling operation.? The vibration encourages the head to seek equilibrium, with sometimes bad results.
Solutions include an improved head lift -- replacing the torsion spring with an air spring (your machine probably already has the air spring), and ALWAYS lock the z axis before you start milling.? Putting a DRO on the z axis can be helpful here because the z axis often moves a little when it is locked (mine moves about .001" down).
If your fine-adjust knob is moving even when the z axis is locked it's probably not affecting the actual z axis position, just messing up your positional accuracy.? This is where a DRO or DI attachment shows its real worth.? They are independent of the crappy z axis drive system.
I would have just suggested you visit the GrizHFMinimill group but many folks in this group belong to that one, too.? However, it would be the one to get input on how owners have tried to address various parts of the z axis problem.
Mark
|
I see you have the 4700 micro - a bit different than the mini that I posted a link to.
Not sure how you'd fix the slop in that...
toggle quoted message
Show quoted text
On 7/25/2017 10:12 AM, 'Johannes' johannes@... [7x12minilathe] wrote:
l.JPG?dl=0
This is the fine-adjuster to LMS 4700 Mill.
Have somebody made a lock for this?
My adjuster is moving (turning) when I am milling, and before I am doing
something stupid, I want an advice from you.
Best regards
Johannes
|
I bagged that whole rack-pinion thing for something a bit more robust:
Actually my wife wanted it changed. She used it when we first got it, said it sucks, and suggested the stepper I did, or something like this:
I can send the 3D model of that if you'd like...Uses off the shelf gears from Boston Gear. Uses the same CNC Fusion ball screw.
I've been using the stepper/Arduino thing for years and really like it. I can get accurate depths that hold.
As to the stock mini mill setup, everyone states you should lock the gibs, or tighten them up. Also you can check your rack-pinion mesh and shim the rack to make it a bit more tight.
I didn't like any of those suggestions. A rack-pinion is great for a drill press; not so much for a mill, at least in my opinion...
//
toggle quoted message
Show quoted text
On 7/25/2017 10:12 AM, 'Johannes' johannes@... [7x12minilathe] wrote:
l.JPG?dl=0
This is the fine-adjuster to LMS 4700 Mill.
Have somebody made a lock for this?
My adjuster is moving (turning) when I am milling, and before I am doing
something stupid, I want an advice from you.
Best regards
Johannes
|
? This is the fine-adjuster to LMS 4700 Mill. Have somebody made a lock for this? ? My adjuster is moving (turning) when I am milling, and before I am doing something stupid, I want an advice from you. ? Best regards Johannes ?
|
Re: Constant surface speed cutting CSS
Thanks for posting, very interesting!!
Youtube had problems loading your video.
I'd like to see a photo of the sliding pot and a wiring diagram.
It is really nice to increase the speed as you get a smaller diameter.
Ralph
|
These are abrasive blades. ? Abrasive work for the cut-off job because only a tiny part of the blade is in contact with the metal. ? Abrasives don't work as well for drilling holes in metal
On Fri, Jul 21, 2017 at 6:58 PM, stan2778@... [7x12minilathe] <7x12minilathe@...> wrote:
?
We also have 14" diamond blades for rebar on the big gas powered cutoff saws, but again, the guys think they are masonry and not very goo for that.
--
Chris Albertson
Redondo Beach, California
|
Re: Constant surface speed cutting CSS
Glad to know that my mini is not the only one that gets pretty loud. :)
|
Constant surface speed cutting CSS
Thought this may be of interest.A mod I did 2-3 years ago.
Sorry, for the quality of the video as I am not?a professional movie maker.
As I regularly cut largish?diameter bar up to 120 mm dia, held in a standard 4" (100mm ) Chuck using special soft jaws, I decided it would be practical?and doable to increase the cutting?RPM?s as I moved to the center.thus constantly changing the cutting surface speed keeping to optimums.
This avoids taking one hand off the cross slide handle to alter the speed on the lathe control box pot and therefore not creating ?"dwell" marks on the surface as you are cutting.
I like to use hands crossing over one another when feeding, that's the reason I made larger hand wheels than those silly "spoke" ?type that came with the machine.
The CSS principle is similar?to CNC lathes using the G96 and cancels with G97 codes.
Very basically, the wiring configuration is a sliding "pot" attached to the top of the cross slide, similar to the types found in recording studios etc. This sliding?pot is wired into the two other pots that control and set the starting and finishing speeds as determined by the type of metal to be cut,? From there to the original pot on the lathe control box. There is a 3-way switch and the 2 ?start and?finish speed pot knobs on the CSS plastic control box that is adjacent to the main lathe control box. The 3-way switch allows CSS and or normal lathe and the center position isolates the CSS and the main lathe pot.
It all works very well.
I fitted my?own gear reduction drive unit to the lathe, that?s why I can get good torque and good cutting out at large diameters without stalling the machine.
Thanks, again?may be of interest to some of the forum members.
John Spain
|
I have one of these at home. I want to put it on my 14" Dewalt electric chop saw, if it works, it would be great. The electric is no where near as fast as the gas saw. I stopped using the dewalt much when i bought a bandsaw .Bandsaws are not as intense as a chopsaw, but chopsaw will cut axles, bandsaw wont.
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Thanks I been looking for something like this my wife does not like the smell of burned carbon.? One of these blades should do the trick. Thanks again.
toggle quoted message
Show quoted text
-----Original Message-----
From: stan2778@... [7x12minilathe] <7x12minilathe@...>
To: 7x12minilathe <7x12minilathe@...>
Sent: Fri, Jul 21, 2017 9:47 pm
Subject: [7x12minilathe] Re: diamond bits
?
I use these occasionally, they work quite well. they seem to disappear from work so i dont know how long they last. Most of the guys think they are for masonry. Nope, cut steel with a standard angle grinder, dry. have one on my cordless grinder, use it like a standard cutoff. Available at lowes too.
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Johannes
Warren LeMay