Author Topic: round column solution  (Read 13597 times)

Offline Pete49

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round column solution
« on: July 30, 2014, 04:55:28 AM »
My simple solution to the round column problem of losing accuracy when adjusting the height of the head was finished yesterday :cartwheel: It was from a system in MEW but was not suitable to my mill/drill (ZX 30)which is a chinese version of the RF30 due to the belt cover. Anyways here's  a picture of my version and it seems to work  :cheers:
Pete   
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Offline Robert Hornby

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Re: round column solution
« Reply #1 on: July 30, 2014, 06:22:34 AM »
That's a really good looking solution to the problem. How accurate do you recon it is? within a couple thou? My drill mill has the same problem so I will make the mod myself.
I have just checked out my mill base and it is far from square with anything, so I guess you just packed the brackets until parallel with other?
Robert
« Last Edit: July 30, 2014, 07:26:29 AM by Robert Hornby »
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Offline PStechPaul

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Re: round column solution
« Reply #2 on: July 30, 2014, 08:04:32 AM »
I have a somewhat similar mill/drill HF 43976 and it has a gear rack and crank where your support is, but perhaps yours is on the opposite side? I can see where your support may help but I think the main problem is torsional movement and that would mostly just bend the bar in your attachment. I found that making the clamps extra tight works pretty well, but I'n thinking about drilling holes in the base and the head, tapping them, and then drilling conical partial holes in the column that will serve to mate with matching conical set screws. They can be loosened if the head needs to be rotated, but otherwise they should help keep it in good alignment with the table, and should eliminate most torsional (twisting) movement.

I would drill more holes in the column at, say, 2" increments, and the 3-1/2" vertical adjustment of the quill should take care of most situations.

Here are pictures of the top and bottom of the column on my mill:





I don't mean to hijack your thread - I just want to show what I have and how I plan to improve my situation. I'd also like to learn more of the details of what you have to see if it would also be applicable. Thanks for your contribution.

Arbalest

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Re: round column solution
« Reply #3 on: July 30, 2014, 02:37:52 PM »
It's a shame the Chinese didn't copy the Koreans like the Germans did!  :Lol:

http://lathes.co.uk/ixion/

Maybe a decent (replacement) rack and some shimming could produce a similar effect?


Offline dieselpilot

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Re: round column solution
« Reply #4 on: July 30, 2014, 04:25:58 PM »
My Arboga has a gib on the gear rack.

Offline sshire

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Re: round column solution
« Reply #5 on: July 30, 2014, 04:41:23 PM »
It would seem that, unless the rack were attached at multiple points on the column, there would be lateral flex in the rack.
The Ixion, according to the attachment, has a "bevel box at the base of the column." What is that? I've magnified the photo and don't see any sort of alignment part.
Best,
Stan

Offline philjoe5

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Re: round column solution
« Reply #6 on: July 30, 2014, 05:02:35 PM »
Someone, somewhere once posted their "fix" for this round column problem.  They firmly attached a laser pointer to the head of the mill, and placed a "target" across the room to position the laser.  I've never done the trig calcs but the claim was that you could move the head up or down and regain the datum you had? 

Anyone tried this?

Cheers,
Phil
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Arbalest

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Re: round column solution
« Reply #7 on: July 30, 2014, 05:14:08 PM »
The Ixion, according to the attachment, has a "bevel box at the base of the column." What is that? I've magnified the photo and don't see any sort of alignment part.

I assume the bevel box is the box on the base with the handle coming out of it Stan.



It's worth mentioning that the Ixion, as with the early Korean ones like the Naerok, have the head fixed to the column so the whole assembly moves up and down through the base. There seems to be at least one clamp (maybe two?) on the base to lock the whole assembly together.

I wonder if anyone has actually tried pinning the rack on the Chinese mill drills and then shimming around the pinion area and making a lock screw?
« Last Edit: July 30, 2014, 05:24:11 PM by Arbalest »

Arbalest

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Re: round column solution
« Reply #8 on: July 30, 2014, 05:15:05 PM »
My Arboga has a gib on the gear rack.

Have you got a picture you could show us?

Online mklotz

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Re: round column solution
« Reply #9 on: July 30, 2014, 05:23:49 PM »
I have to admit that I have my doubts about Pete's rod solution.  With the typically heavy heads on a mill-drill, I would expect the rod to bend easily and unpredictably without the operator being aware of the bending.

However, I'll reserve judgement until we see the results of some measurements.  Moreover, its utility depends on how much accuracy is expected.

Long ago, I experimented with the laser solution.  A laser was attached to the head and aimed at a steel wire plumb line on the opposite wall of Garaj Mahal.  After elevating the head, the head was tweaked so the laser again was on the plumb line.  Accuracy was measured with a DTI in the chuck riding against the vertical face of a trusted angle plate clamped to the table.

In a number of blind (adjust head without being able to see DTI) tests, I got measured misalignments in the ten thousandths range - not great IMO.

I attribute a lot of the error to being unable to reliably put the laser spot on a target that far away.

So I suspended a good first surface mirror on the wall and reflected the beam back to the mill-drill head.  Nice concept since it doubled the adjustment lever arm and put the target on the mill-drill head where it could be easily seen.  However, the amount of fiddling associated with this arrangement is beyond my, and I suspect anyone's, patience range.  It's simply not practical.

My final solution has been to not move the mill head.  A combination of tool-holding collets, screw-machine drills, cut-down reamers along with careful planning of machining sequence makes the need for head movements rare.

If I'm forced to move the head, I'll use the DTI against trusted vertical reference approach.
Regards, Marv
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Offline Pete49

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Re: round column solution
« Reply #10 on: July 31, 2014, 05:28:25 AM »
Paul crank is on the other side. I don't rotate my head as I haven't needed to and had thought of welding the rack to the column but still think I have solved the problem for now. I shall see how it goes.
Robert my mill is only square at the head and so I attached the base to the base of the mill column and packed it out about 1/16" because I didn't allow for the top of the T moving as I welded 1 side completely after tacking as I forgot to do a bit each side. The bar is 1.120" SS prop shaft I had laying around and it was accurate to drill bit it went neatly into the same hole within 5 thou or less. As the head is clamped before any machining or drilling is done torsional twist isn't a consideration. When I drilled a test hole and then moved the head up to the top of the bar then down to the next drill size (1/4" then 3/8") it was in the same alignment as I replaced the 1/4" drill bit and it went neatly into the pre-drilled hole.
Please remember I'm self taught and have learnt mostly by mistake :shrug: but I'm happy with this as it is a big improvement to what was a pita before.
All very nice to have the better machines and I would love a dovetail version but money only goes so far and this is just one of my hobbies though the most used one. I do however subscribe to Marv's method when I need very precise parts.
Pete
« Last Edit: July 31, 2014, 05:34:44 AM by Pete49 »
I used to have a friend.....but the rope broke and he ran away :(....Good news everybody I have another friend...I used chain this time :)

Offline BillTodd

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Re: round column solution
« Reply #11 on: July 31, 2014, 09:14:33 AM »
This is my solution:

http//:wktodd.webspace.virginmedia.com/drillmill/page4.html

RF30 CVT and other modifications: <a href="https://www.youtube.com/watch?v=7y7pPm5vPys" target="_blank">http://www.youtube.com/watch?v=7y7pPm5vPys</a>
« Last Edit: July 31, 2014, 09:18:23 AM by BillTodd »

Offline PStechPaul

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Re: round column solution
« Reply #12 on: July 31, 2014, 09:37:44 AM »
Those are some very clever mods. The wishbone stabilizer, it appears, keeps the head from twisting with respect to the base, yet allows the head to be moved up and down on the column, with power feed, yet! Very nice!

Offline Pete49

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Re: round column solution
« Reply #13 on: August 01, 2014, 07:53:36 AM »
Nice mods Bill. power feed for both is on the agenda but the X-Y is first to do ...getting sore arms winding it back and forth :LittleDevil:
Pete
I used to have a friend.....but the rope broke and he ran away :(....Good news everybody I have another friend...I used chain this time :)

Offline BillTodd

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Re: round column solution
« Reply #14 on: August 01, 2014, 11:53:50 AM »
Quote
power feed for both is on the agenda but the X-Y is first to do

Just working on a X axis power feed for mine.

My neighbour gave me a couple of rise & recline bed jack units, with nice German made motors and gear parts. I've butchered one to provide the worm drive and bodged it together on the end of the X axis.

Offline Ian S C

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Re: round column solution
« Reply #15 on: August 01, 2014, 03:07:13 PM »
There was a mod article in ME, maybe in the 1990s, there may also have been one in MEW.  The one I'm thinking of had a fitting on top of the elevating gear box, and used the side of the rack as the guide (can't remember) maybe a ball race each side of the rack.
                                     Ian S C

Arbalest

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Re: round column solution
« Reply #16 on: August 01, 2014, 03:21:18 PM »
That sounds like a good idea Ian.

Offline techonehundred

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Re: round column solution
« Reply #17 on: August 01, 2014, 04:01:13 PM »

Offline Mr Moo

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Re: round column solution
« Reply #18 on: May 18, 2018, 10:00:37 PM »
All very excellent.  The first of several modifications to my new warco 30......

 

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