Model Engine Maker
General Category => Chatterbox => Topic started by: zeeprogrammer on January 08, 2020, 11:20:18 PM
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I'm trying to get my machines ready for the next project (ha ha).
I'm using Rollie's method to square the head to the column.
Easy enough (ha ha) to square in the Y (i.e. left to right) direction but...
I used a 1/2" collet with a printer roller bar and noticed that in the X direction, there was a bit more than 3 thou change as I moved the head up or down.
I have no reason to think the printer roller bar is bent. I have plenty of reason to think the head is not square to the column.
I have no idea whether that can be corrected or if it needs to be. That is, whether squaring the column to the bed will take care of this or whether it's enough to worry about.
I'm not a precision type of guy (in that my projects do not require high accuracy) but there's no reason why the machines can't be better than I need.
I have a PM-25MV.
Thanks for your help.
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You need to find a happy medium where the head will tram and move perpendicular to the table and the quill will move perpendicular to the table as unlikely you will get both exactly the same and measuring quill tram is not easy as you have an unlocked quill which by it's very nature has a bit of movement and the action of pulling on the quill feed can affect things.
I think your mill has a tilting head so X can be trammed with that, to do Y you would need to shim under the column.
This is the SX2.7, spindle tram 0.006mm over 170mm that's two tenths of a thou over 6 1/2", column feed average 0.015mm over 50mm but Y quill feed is a little off at 0.05mm over 50mm but all not really worth worrying about for the engines that I make so you should be OK.
https://www.youtube.com/watch?v=jp4sqaAw11Y
As you can see both the leading and trailing edge of a flycutter leave marks which is a good indication that tram is about right, think this was actually on the X3.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/44290/783228.jpg)
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Zee I think you have swopped over the X and Y axis to try to confuse me first thing in the morning :headscratch: Convention is that moving the bed left and right is the X axis, in and out is the y axis.
When you tram you need to have the quill locked, and the column (Z axis) locked, otherwise as JB said the play in the movement will throw the tramming out. Lock everything up then Tram at one location, unlock everything move the opposite of the movement, relock everything then Tram again.
If you find that the Y axis is out this could be due to poor machining of either the back of the Milling head where it attaches to the column or the front it bolts to but more likely the bottom face where the column mounts to the back of the table. Sadly not unheard of :-\ Shimming will correct it ;)
Jo
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Thanks Jason and Jo.
(Yes, you're right Jo, I got X and Y swapped.)
I should have mentioned in my post that I was initially tramming the head to the column. Once that's done then I can tram the head to the bed.
I'm nearly sure I'll have to shim the column to tram the head to the bed. (Probably needs shimming in both X and Y.)
To tram the head to the column, I had an indicator mounted on the column and touching the bar. The bed has no part to play in this nor does the column to the base.
Indicating and tramming the head to the column in the X direction is 'easy' enough.
It was when I indicated in the Y direction (again, head to column) and raised/lowered the head that I saw a 3 thou+ change over a distance of about 6".
I have no clue how to correct for that (or if I need to).
I haven't raised/lowered the quill, just the head. That makes me wonder about the squareness of the quill to the head.
Perhaps I'm doing this wrong?
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Zee, here's how I aligned my mini-mill (years ago):
https://www.homemodelenginemachinist.com/threads/mini-mill-spindle-column-alignment.5337/
Shims for the Y-alignment first, then taking advantage of some tolerances in the head mounting bolts and holes for the X-alignment.
Regards,
Rudy
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Thanks Rudy. That was very helpful.
You mentioned you trammed the head to the column in the Y direction first. I was watching a video and they had trammed in X first.
Is there a particular reason why you went with Y first?
Today has been very frustrating. Mainly trying to get a dial test indicator mounted to the column using a magnetic base. It keeps slipping.
I've tried clamping but can't seem to get a good grip. Also tried double stick tape and that was even worse.
I'm wondering if sanding the column a bit for a rougher surface would help.
Having said that, I noticed Rudy removed the head and column and trammed the head to the column while it was laying down.
That would seem to make things a lot easier and could solve the magnetic base issue but this thing is a beast and I'm not sure I have oomph to move it (at least not without an engine hoist).
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Zee have you tried mounting the indicator on a rod held in a chuck in the spindle and run it up and down the column?
This will tell you if the face between the milling head and the column is nor square. If not you could add a shim ;)
Jo
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Zee have you tried mounting the indicator on a rod held in a chuck in the spindle and run it up and down the column?
This will tell you if the face between the milling head and the column is nor square. If not you could add a shim ;)
Thanks Jo. No I haven't tried that. I'm using Rollie's Dad method so the indicator needs to be on the column.
Shimming in X shouldn't be necessary - I can unbolt, align, and bolt again.
If I find Y out of tram then shimming will be necessary.
I/we keep talking about the head but isn't it about getting the quill square to the column?
I asked this before but no one has responded...isn't there the possibility that moving the quill up and down (leaving the head stationary) also a potential source of out-of-squareness?
I see videos where they raise/lower the head during this process...but nothing about the quill.
I'm probably overthinking a lot of this.
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...You mentioned you trammed the head to the column in the Y direction first. I was watching a video and they had trammed in X first.
Is there a particular reason why you went with Y first?...
Zee, loosening the spindle head enough to insert shims to align the Y-axis would allow the spindle head to move side to side, invalidating any previous X-axis alignment. That's why I did the Y-axis first.
Also, I dug out the paint and dirt in the seam around the spindle head and carriage with a knife to get rid of any paint or dirt there that might foul the fit between the two.
Regards,
Rudy
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Zee look at my video again where I tested both feeding using the quill and the head.
Spindle to table is the most important, where quill or column can come into it is if working on a tall part where you may have to raise the head a lot then there is a risk of the X-Y position of any holes for example being off. Also any deep holes could suffer for example if you have the head and retracted spindle trammed that will be fine if feeding say a boring head by lowering the whole head but if feeding with a quill that is off then the hole will be off by the same error which will get worse the deeper it goes.
Unless you have been finding major problems with te work produced (that are down to the machine) I would just concentrate on getting the retracted and locked spindle trammed to the table.
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loosening the spindle head enough to insert shims to align the Y-axis would allow the spindle head to move side to side, invalidating any previous X-axis alignment. That's why I did the Y-axis first.
Thanks Rudy. I was thinking that late last night. Good to have it confirmed.
Thanks Jason. That's just what I thought.
Now as to shim material...
I have feeler gauges but the thinnest is .0015" (.038mm) which is a bit more than twice the thickness of aluminum foil (which I've read other people have used).
Any other suggestions?
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Both my X3 and the SX2.7 use old bits of feeler gauge
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Zee from Zen and the Art of Motorcycle Maintenance beer cans make good shims. I have used beer can shims a few times.
Cheers Dan :DrinkPint:
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Well I did some measuring and it seemed I was pretty close to tram so I did some cutting with a face end mill cutter (flycutter with inserts).
I ran the cutter both ways twice and while I got the same results for each direction, each direction differed from the other.
I used power feed.
Thoughts?
1st picture shows feeding to the right and it seems there's decent cross-hatching.
2nd picture shows feeding to the left and there's no hint of cross-hatching.
Scratches you see are from wiping off the plate with a paper towel.
[EDIT:] Other than adjusting the head to the column in the X axis, I haven't done anything.
If it weren't for the 2nd picture, I should be feeling happy, no?
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Zee,
I would love to say I have something to add, but I really don't. I have seen where people have had to tram their column mill and shim it here and there. My mill is a column mill as well but I haven't done anything that led me to believe it wasn't trammed.
Art
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I'd say you are probably close enough in X not to upset things, I would say the left side of the cutter is slightly low hence the pattern in the second photo.
If you look at the first photo the cross hatch only shows where both leading and trailing edges are over the work so there is a bit of ride up going on which the "blunter" inserts will intensify, try it again with a really sharp flycutter and no rounding of it's corner and just a few thou cut.
Also try the same cuts in the Y direction
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Thanks guys.
Jason, I did the Y direction. In the -X direction I got cross hatches but in the +X direction a little less so.
Seems I'm close but can't smoke my cigar yet.
On a different note...today really sucked.
You all know I'm up for surgery on my right shoulder (can't move in a couple of directions) and now my left thumb got injured and I can't grasp. Not to mention the knees are out.
This is all especially bad what with gardening season approaching and T needing my help. She (who must be obeyed) will not be happy.
It's making me question having such large machines. I have thoughts of selling them and going for smaller.
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Understandable you should feel that way........but maybe wait until after surgery and see how you feel? Once recovered and through some PT you may feel more able to cope..
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On a different note...today really sucked.
You all know I'm up for surgery on my right shoulder (can't move in a couple of directions) and now my left thumb got injured and I can't grasp. Not to mention the knees are out.
This is all especially bad what with gardening season approaching and T needing my help. She (who must be obeyed) will not be happy.
It's making me question having such large machines. I have thoughts of selling them and going for smaller.
Well Zee...............I'd certainly agree with you that your day sucked for sure! >:( I hope things get on the upswing soon. They never told us about all this stuff in "The Handbook of Getting Older"! :shrug:
On a "lighter" note :Lol: if you decide to "see the light" and move to "lighter" machines..............Chris, Bill, and myself will welcome you.
:cheers: Jim
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They never told us about all this stuff in "The Handbook of Getting Older"! :shrug:
Probably on the same shelf as "The Handbook of Growing Up".
I've never seen said handbooks but have the next best thing in parents and grandparents.
(Grandparents are long gone but I'm fortunate to still have my parents.)