Advice on large purchase please
|Cabinet Enforcer||24/04/2018 13:16:24|
|25 forum posts|
No you haven't, you aren't measuring anything meaningful there, there is more than 1 axis of freedom.
You said you had trammed the head, but video 2 above clearly shows it is miles out. Step away from the spanners before you make it worse, go and have a cuppa, then engage the brain.
|2681 forum posts|
I agree with gas_mantle, the tests themselves are suspect. (Close tolerance testing is rather difficult!)
Have a look at this photo. Does it show that my table isn't flat, or does it show that one or both of my set-squares are untrustworthy in the sideways direction? (This might chime with MickB1's comment).
The answer is that my set-squares are only trustworthy in one plane. The one marked 'Conforms to BS939' is particularly bad. Sticking a DTI on the flat-side and running the quill up and down produces errors consistent with the blade leaning and flexing.
The test as performed by STK008 is better - he runs the DTI up and down the safe edge of his set-square, reducing the effect of a bent blade (if he has one), and eliminating any tendency to flex. But there's another issue: when you ramp the quill up and down, there is nothing to stop the quill rotating slightly. Trouble is that a tiny circular movement appears as a big error on the DTI. You can't tell if the error is due to the quill turning, or because it is misaligned in some way.
Next photo shows a slightly better set-up. The DTI is fixed and bears against a rod in the collet. This makes my quill look considerably better than when I tested it using STK008's set-square method.
A further improvement is gained when the measurement is taken with the spindle turning. It still bounces about but the effect tends to average out. There are still several sources of error; how straight is my test rod; are the collet and collet chuck in good condition; is the taper clean; why aren't I using the biggest diameter rod I can fit to the machine?
It's possible that STK008 has a faulty mill, I'm certainly not trying to prove otherwise. If it's wrong or you're unhappy, talk to Warco. But I agree with gas_mantle at this stage - I'd give the mill and yourself some practice cutting metal first.
12543 forum posts
Send a copy/link of that last video to Warco and ask them if it's acceptable.
John, these small mills generally use the quill to put on a cut that is why it has the cheap digital reader on the quill.
|116 forum posts|
I've just checks that the tram left to right is good and it is over 20mm I get 0.002".
Tramping back to front I get 0.006" with no way to fix it as the head does not nod.
I have just places a verdict in the er32 collet and zeroed it on the bed in one corner and moved the bed from back to front I get no more than 0.001" and left to right I get 0.002" which is good seeing g as the bed a big .
So it's not the table.
If I lock spindle from rotating then do test again seen in my last video and still get same results then does that show any thing?. I know what u mean about the collet rotating yes that would give a bad reading BRB gonna do that. Edit Yep that's right it has a fine feed on quill so if I'm right and I extend quill further down with what I'm thinking is wrong it's not gonna be very good.
Edited By STK2008 on 24/04/2018 13:36:09
|David Standing 1||24/04/2018 13:35:15|
|979 forum posts|
I agree, and I would go one step further...........
Although I use it because sometimes it is the only practical method, I am not a great fan of a DTI on a magnetic stand with three joints in it, as again it introduces some margin for cumulative error. The minimum I do is try and get all the rods as short as possible.
Were I conducting that test, I think I would be inclined to do away with the DTI stand altogether, and (carefully) clamp the lug on the back of the DTI directly in to my machine vice, the latter being bolted to the table.
|436 forum posts|
To check if the quill is perpendicular to the table, proceed as follows :
Fully extend the quill and clamp it.
Then repeat the process, but with the dial gauge set on the side of the quill & "wipe" it with the Y axis (table moving front - back) rather than the X.
The readings "should" be pretty well the same top & bottom from both setups - my guess is that the side value will be close & the front value will be out.
|John Rudd||24/04/2018 15:29:12|
|1077 forum posts|
I assume your comment was aimed at me.....?
I must have missed the reader ......never mind...its late in the day and I've been busy with other stuff
Edited By John Rudd on 24/04/2018 15:30:21
|116 forum posts|
|I shall try that mgnbuk thanks|
I did message warco and they just replied saying
We are sorry to learn of this. Can you slightly slacken off the larger of the two nuts which lock the head. Only the small nuts needs to be tight to lock it.
There is two nuts one through centre the head pivots about and one just below which is the locking nut I assume he means the centre nut to slake it off a tad?.
Edited By STK2008 on 24/04/2018 16:46:13
|David Standing 1||24/04/2018 16:47:32|
|979 forum posts|
I would ask the person at Warco that sent you the message what he meant!
|Mark Dickinson||24/04/2018 18:59:44|
|44 forum posts|
STK, to tram the head fore and aft, do a google for G0704 3 Bolt mod. You may fid that will help fine tune the head.
|116 forum posts|
Ok then did what I think Warco meant and made no diff.
I redid my test when I ran the DTI up and down the Z column just to see if the spindle spun it realy does not its to stiff for it to rotate etc plus as you can see the DTI returns to zero every time if the spindle had spun it would read some thing else.
I am slowly loosing the will to live I have spent 3 days on this and every test I do all be it not 100% the best gives same sort of results.
I did what mgnbuk
Believe it or not I got 0.001" so nothing so the quill is square in the casting so to speak.
So only thing it can be is the head not sitting on the Z axis square front to back? off course this is ok left to right as I can tilt the head but not nod.
In the videos its off that much the verdict actually leaves the surface completly.
in both these tests the spindle did not spin.
I can only think of a few things that would cause such an issue.
A . Head not correctly seated on Z axis piller
B. Quill on the pee (but seems ok)
Would a set of these be better to move the quill up and down on rather than my engineers square?
Edited By STK2008 on 24/04/2018 20:41:40
|1531 forum posts|
I agree, this is what I was taught as well. I only ever use the quill on my VMC for drilling.
I don’t know why some compromise the rigidity of their mill by extending the quill instead of raising the knee or lowering the head but they do.
|Andrew Johnston||24/04/2018 21:53:23|
3730 forum posts
I also use the quill on my vertical mill with a boring head, when the power downfeed comes in useful.
As has been said it is pretty difficult to set up a measurement so that one, and only one, possible geometric error is being measured. It's even more difficult to get consistent results, and if the measurements are not consistent all bets are off. The OP would be best advised to stop worrying about a potential error and just use the mill to make some parts to start with. If indeed there is a geometric error it will show itself soon enough.
|Michael Gilligan||24/04/2018 22:36:01|
10976 forum posts
It's impossible to answer that meaningfully, without knowing the accuracy of your square.
But, I can see no reason to expect them to be any more accurate than a decent test square.
... is their squareness specified ?
Schlesinger illustrates the use of a square, and mentions in the text that it should be clamped to the table.
In general terms, I believe your test method is correct.
Checking the square; clamping it to the table; and improving the rigidity of your indicator-mount would all improve confidence in your results though.
|116 forum posts|
|So yeah from that diagram I'm seeing the head being trammed while moving the table up which would be what I'm doing when I move the whole head up and down|
Then I see in the diagram moving the quill up and down to also check that.
Now when I move the head up and down if I'm not wrong it shows that my z axis column is fine as I get no more than 0.002" over about 60mm or so I can live with that.
But as soon as I move the quill up and down its game over 0.015"+.
I understand what every one is saying g.
Is square well square yes I'm sure moving head up and down would show more than the 0.002" I was getting g if not?.
So I removed that and used the z axis column same issue.
I then made sure spindle is not moving I'm sure it's not its to stiff to rotate and I did not see any movement at all plus verdict returns to my original zero.
I'm not going to lie this issue is gutting me I've saved for a very very long time I just want to make stuff etc.
I will cut some metal tomorrow and see what I get.
Thank you to every one for assisting me with this truly do appriciate this.
P.s I'm on me phone and it's terrible on this forum the window I have to type in is about 2cm big what's up with that? Lol.
|2681 forum posts|
I fear there's a distinct possibility you're winding yourself up. Another explanation to A. and B. is that your measurements are suspect. There's much more to taking reliable measurements than common sense and it's easy to make mistakes and mislead yourself. (As I know to my cost!) At the moment I can't tell if there's a problem with the mill or not; I can see why you're suspicious but the evidence is flawed.
Here's an example. I've never tried using a lever DTI sideways as shown in your video.
Isn't it likely that the lever will tend to flex and scuff across the surface? I don't know, and bet you don't either. Another issue - the DTI is mounted on the end of a long bendy rod acting as an amplifier - a small movement at the spindle end will register as a much bigger movement on the dial. Good if that's the aim, very bad if it happens by accident. The video suggests it's accidental.
What I suggest is that you put your measuring kit in a box and swallow the key. While it's temporarily in transit use the opportunity to cut metal. Try the mill for real and see how you get on. Experiment and ask more questions. Add to your experience, gather more evidence and take it from there. With luck all is well; if not Warco are only a phone call away.
Edited By SillyOldDuffer on 24/04/2018 22:54:20
|not done it yet||24/04/2018 22:50:46|
|1731 forum posts|
The classic method of checking a woodworker’s square was to scribe a line across a face or side and then turn the square around and scribe another line at thecsame origin. If both lines coincided, the square was good.
Same would apply to an engineering square but using a dial indicator to check any deviation and in which direction.
|116 forum posts|
|Yeah I see your point about the sideways verdict.|
I did do same test with dti though.
I understand the jig is um rather long and could flex.
I will place my verdict directly into an er32 collet tomorrow so no jig at all the run it up and down my engineers square which I shall also check is square but I'm pretty sure.it is but I will check.
I'm going to cut metal tomorrow honest lol.
I've read that saw toothing will happen on a none trammed head etc so will do a few passes over metal moving the table across some to cut a largish area and see what finish I get.
If I had a flycutter I would cut a large surface I would expect to see it uneven if I then checked the surface with my verdict chucked into me er32 collet but hey I ain't got one so can't lol.
Thanks again all .
300 forum posts
Silly Old Duffer has hit the nail on the head, put the measuring gear away and cut some metal.
I can't believe after all the hype that it may take a few days extra for delivery you then spend 3 days trying to measure a fault that quite possibly doesn't exist without cutting metal first.
I'm no expert but I have the same machine from a different supplier, all I did was cut scrap for a week then start measuring, a bit of an adjustment to the gibs and a squirt of oil is it needed once it had been used a bit.
|1531 forum posts|
Agreed, cut some metal and see how it performs. And get a Flycutter, something with about a 2” dia head. They are extremely useful for getting nice flat surfaces on modest sized workpieces.
This thread is closed.
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