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-   -   Rong Fu Mill/Drill head lift guide (https://www.shopfloortalk.com/forums/showthread.php?t=46294)

cutter 07-04-2016 06:11 PM

Rong Fu Mill/Drill head lift guide
 
This is food for thought for tackit in the midst of his travails with his mill/drill. :)

Some of you may remember I built a motorized head lift for Mildred a couple or three years ago. I was hoping that it might at least minimize the rotational drift from registration experienced with round column mills.
It did not.

I have posted a You Tube video which demonstrates that she still shifted both to the right and to the left a 1/2 an inch or so under travel.
The indicator in this video is not touch the test bar; it is only a pointer to show how much drift there is.

So I worked for about a year, off & on, to build a guide bar to at least minimize this rather glaring deficiency so that poor old Mildred could feel prouder of her performance. This was inspired by the one Mark Ball posted a couple of pictures of 2 or 3 years ago.
I did not post this build project because of the tedium involved, the false starts & do over's and the general frustration all that entailed, scattered over most of 2014.

But I do have another You Tube video showing the result. It limits her error to plus or minus .005" and she usually settles down to about zero when the motor switches off.
Not perfect but honestly, for the kind of work I get around to doing it is generally good enough & certainly a lot better than trying to use that damned crank, which now resides in a drawer.

Head lift guide video # eleventyfortyone or something. :)
In this case the indicator is in contact with that old WWII boring bar from my grandfather's tool chest.

clive 07-04-2016 07:53 PM

Cutter, I have a mill/drill ( but with a tilting head) and the round column is a pain, I tried to find the alterations you did to steady it but couldn't. Do you have a link to that?
Clive

dubby 07-05-2016 08:33 AM

That's pretty darn good, and better than most will ever get out of their machines. Great job!

tackit 07-05-2016 09:03 AM

That's really great work cutter, I'm impressed. :D

cutter 07-05-2016 12:23 PM

Quote:

Originally Posted by cutter (Post 663495)
I did not post this build project because of the tedium involved, the false starts & do over's and the general frustration all that entailed, scattered over most of 2014.

Quote:

Originally Posted by clive (Post 663503)
Cutter, I have a mill/drill ( but with a tilting head) and the round column is a pain, I tried to find the alterations you did to steady it but couldn't. Do you have a link to that?
Clive

I did not post a thread about it, Clive. I took hundreds of pictures along the way, most of which are details but they are disorganized and probably not very helpful unless I put a lot of time into trying to recover my memory of "what was that all about?" It really was a frustrating build because this old mill was downright determined to defend her right to choose to rotate. I was very surprised at how much torque was involved and how much force it took to overcome it.

I have looked at the pictures, trying to find a decent overview and nothing I have would be very helpful.
However, this thing really does work so it is doable. I'll try to get some decent pictures to show you here.

clive 07-05-2016 06:33 PM

Thanks, I guess a shot of the finished article, those who are keen should be able to work it backwards from there.
Clive

MarkBall2 07-06-2016 07:55 AM

3 Attachment(s)
Now why didn't I think of that?????

cutter 07-06-2016 11:41 AM

Quote:

Originally Posted by MarkBall2 (Post 663621)
Now why didn't I think of that?????

Quote:

Originally Posted by cutter (Post 663495)

This was inspired by the one Mark Ball posted a couple of pictures of 2 or 3 years ago.

ummmm?

MarkBall2 07-06-2016 01:11 PM

Quote:

Originally Posted by cutter (Post 663634)
ummmm?


electric lift (head slap)

cutter 07-09-2016 04:49 PM

5 Attachment(s)
Quote:

Originally Posted by clive (Post 663582)
Thanks, I guess a shot of the finished article, those who are keen should be able to work it backwards from there.
Clive

Now Clive, surely you've been around here long enough to know me better than that. :)
However, I will try to be more brief than my usual.
I've been noodling around in the pictures for a couple of days trying to reorganize what my thoughts were from 2013 and '14 when I was pecking at this project.

First of all I have some Thompson linear bearings & a 3/4 inch rod from an old laminating machine or something that I dug out of a dumpster behind a print shop. I just had to try them to see how that worked.
Don't do that.
Linear bearings have way too much play in them.

Second thing, the castings on the head and on the base of these Rong Fu or Harbor Freight or Jet or whoever puts their names on these mill/drills do not have any flat surfaces that are perpendicular to the spindle. So don't think that you're going to be able to bolt any kind or right angle mounting bracket to them & have a useful basis for tracking in line with the column or the spindle.

1 - 5. So I determined that Mark has it right with making a yoke to attach to the top of the column. I made mine from a small slab of 1/2" aluminum plate that I'd had for over 20 years. First I roughed it out on the old Delta bandsaw & milled the straight edges just so they'd be smoother.

I rough cut the semi-circle on the vertical bandsaw then used a flycutter in reverse to cut to the pencil line I had guesstimated before I started cutting. You can imagine my astonishment to find that it fit perfectly to the column on my first attempt. The damned thing actually fit so snugly that it would hold itself to the column with no weight or pressure on it.

So I very gingerly milled a slot in the center of the yoke to fit over the rack because this attachment has to fit on the crank side of the head. That's where the rack is.

Then I made a "headband" to hold the yoke to the top of the column.


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