dc309
Seasoned Member
Posts: 146 
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Post by dc309 on Jul 10, 2015 18:40:42 GMT
Hi all, I'm having a problem milling these blocks up. I'm using a 2" tipped cutter but I'm getting a ridge in it but I don't know why? Could anyone shed any light on it?  Regards Dan |
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Post by vulcanbomber on Jul 10, 2015 18:55:07 GMT
Head of the machine isn't square to the fixed jaw of the vice.
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Post by gwr14xx on Jul 10, 2015 19:06:01 GMT
It depends on the type of machine you have. If you move the table in or out to take the second cut, the head is not square to the movement of the table. If you move the head in or out for the second cut, the cutter is not square to the travel of the head. If it was just the cutter out of square to the vice jaw, you would still generate a flat surface, but it wouldn't be square to the face that was against the fixed jaw.
Eddie. |
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Post by Roger on Jul 10, 2015 19:58:59 GMT
You can check the squareness of the head by taking everything off the table and mounting a dial gauge on the spindle. I use a magnetic base and extend the arm so that with the spindle in the centre of the table, you can turn it through 180 degrees and see how perpendicular the axis of the spindle is to the face of the table.
Depending on the type of mill you have, you may be able to adjust it in both planes, one or none. I can only adjust mine in one direction which I find annoying.
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Jul 10, 2015 22:25:24 GMT
The technique Roger describes is called "tramming the mill".
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Post by steamcoal on Jul 11, 2015 6:35:59 GMT
This is just one of many tutorial YouTube videos. www.youtube.com/watch?v=U07X_0oo74oIt is worthwhile just checking the alignment every once and a while. I am new to machining myself but know that a bit of heavy cutting or a knock can upset the accuracy especially with a lighter type of machine. |
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jul 11, 2015 21:45:58 GMT
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dfh
Hi-poster
Posts: 197
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Post by dfh on Jul 11, 2015 22:19:41 GMT
Dan
I have a Super Lux and if it is the same as mine the column is bolted to the base, so to get the setup correct you need to shim under either the front or the back to tilt the column forward or back. Just make sure the head is locked up tight to the column dovetails when checking.
David
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Post by GWR 101 on Jul 11, 2015 22:38:09 GMT
Hi Dan, if it is out back to front you should be able to tell where the shim needs to go and how much by which way the step in the work is and how high. If you want to convince yourself that's what is causing the problem try a small cut using the Y axis and see if the leading or trailing edge of the cutter is cutting. We had a similar problem on the Society miller a few weeks back, but that was just the head angle, hope this helps regards Paul
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Jul 11, 2015 22:48:10 GMT
hi dan,
i assumed you locked the head when taking your cuts?
it may just be a case of too high a speed and too fast a feed. cast iron for a good finish requires (on my antiquated machinery) a very slow feed. using more than 2 passes ie taking cuts 1/4 of the tool dia will give a much better finish, but takes more time!
roger's advice is as usual excellent and shouldnt take more than a few minutes to check with a DTI if you have the correct bits to go with the DTI. it is well worth making up these bits if required.
cheers,
julian
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Post by rogsteam1959 on Jul 11, 2015 23:37:42 GMT
Hi Dan,
I wouldn't use those cutter on this mill. This kind of mills are not rigid enough.
Put your hand on the vertical column and you feel a lot of vibration.
On YouTube you can some video from guys who made a frame for the vertical column and srewd it to the wall behind the mill to reduce the vibration.
I suppose your cutter tips are not really sharp like most of these tips. Try to find tips that are designed for easy and silent cutting. This tips are better for this mill.
Cheers
Michael
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Post by Roger on Jul 12, 2015 6:28:50 GMT
The point Julian made reminded me that I forgot to say that you should lock the quill when tramming the head else you will get a false reading. On my machine there's a significant movement of the spindle axis in the X/Z plane when the quill is locked up. You can see what happens to yours by tramming it with it locked up and then release the lock on the quill. Obviously you should always mill with the quill locked up, but you need to be aware of this error because it can catch you out when you drill holes with the quill unlocked after milling operations.
On my machine, I've scribed a line on the locking handle boss and another on the machine body so that I can always tighten the quill to the same position and thus remove some of the variability.
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Post by peterdanastas on Jul 12, 2015 11:19:05 GMT
Head not square to job or tips blunt
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jul 12, 2015 16:49:40 GMT
I've done as you suggested Roger! I put my mag base on the spindle and rotated it round 180 degrees - From the back (nearest the column) to the front, it gains 0.015"! No wonder I was getting grooves in my work. Is this normal for a new machine?
Regards,
Dan
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dfh
Hi-poster
Posts: 197
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Post by dfh on Jul 12, 2015 17:31:24 GMT
Just looked at mine and it looks like I have put about 12thou of shims around the front to bolts
David
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Post by Roger on Jul 12, 2015 18:52:59 GMT
I've done as you suggested Roger! I put my mag base on the spindle and rotated it round 180 degrees - From the back (nearest the column) to the front, it gains 0.015"! No wonder I was getting grooves in my work. Is this normal for a new machine? Regards, Dan I don't know about the build quality of Chester Mills, but I have to say that it doesn't sound like they've set it up at all right. I'd ask them for a specification and see if they are prepared to come and set it up properly. If not, you'll have to shim it yourself, not an ideal situation really. You may get it better than they do though, at least you'll have an interest in getting it as good as possible. |
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jul 12, 2015 19:29:20 GMT
I'll be on the phone first thing in the morning!
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Post by springcrocus on Jul 12, 2015 21:57:23 GMT
Maybe I am expecting too much but if I was paying two grand for a milling machine I would expect the column to be square to the base within a tenth or two of a thou. Because the column is bolted to the base, an extra fiver on the cost to have four or more adjusting screws (tramming screws) in the clamping flange would make all the difference. Having to shim a brand new machine? Sorry, I thought this thing was a precision instrument. I can buy a hammer and chisel for a few pounds. Send it back!
Steve
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jul 12, 2015 22:01:26 GMT
Well said Steve. I've had no end of bother with it as it's already been back once... Like you say, when I paid my money I expected it to be right and not have to faff around with it. Ah well, these things are sent to try us - I think it'll be one of those Monday mornings for Chester tomorrow!
DC
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Post by springcrocus on Jul 12, 2015 22:42:54 GMT
I know this is preaching to the converted but consider the following scenario.
I purchase a new car. A few weeks later, I notice that the tyres are wearing badly on one side and take it back to the garage.
"Ah!" says the representative, "It needs the tracking adjusted"
"Why was it not adjusted correctly at the point of manufacture?" asks I. "And who is going to pay for new tyres?"
"Ah!" says the rep, "Nowadays we wait to see if the customer has a problem and THEN try to fix it. Oh!, and tyres are consumables and not covered by the warranty. Sorry."
I can assure you, the representative would spend some time extracting the logbook from a bodily orifice that would not normally be a home to said document.
I believe the correct words are "fit for purpose" under the trades description act.
Good luck,
Steve
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