Maintenance and setup checking my mill

I think you are sensible in deciding to leave it alone. Tests like this are really very sensitive and can show inaccuracies that are never apparent on your work in the general run of things.

It’s useful to know where the shortfalls are in a machine even if it’s too much bother to correct. Often you can arrange the job to minimise the shortcoming and at least you know what the limits are likely to be.

regards Martin

To make trimming easier and more trouble free I got a new car brake disc and use that on the table

It eliminated the problems associated with the dti plunger dropping into the t slots and questions about has the setting changed. £10 on the bay, well spent

once you correct the nod  extend the quill and mount the dti on the table and raise/lower the head to check the quill, but correction of any error here is a much bigger problem. 

don’t ask how I know…….

Edited By Zan on 20/03/2023 09:58:14

I'm pretty much in the same camp but, as always, it depends on the type of work being done and the personality of the operator.

Most of what I do it old-fashioned 'fitting', in which my machines and workshop skills only need to be good enough to get parts to mate. I don't expect measure to better than ±0.02mm (about a thou), and only own a basic micrometer. None of my measuring tools are calibrated. Building to plans, I approximate, and then fit critical junctions together by using the parts themselves as gauges and references. I don't own slip gauges, or anything capable of reliably reaching down to ±0.002mm. I've experimented with 'fitting' using only spring calipers and a steel-rule : works well enough, but requires time and extra care. I'm also a slob, going so far as to accept poor finish and even looking for opportunities not to machine parts at all!

My exact opposite would be a fusspot, the sort of worker who likes everything 'just so' before starting work, who wants to do the best possible job on everything. Where I'd be happy with an el-cheapo adjustable spanner, he's gpt a set of carefully researched Swiss aero-space spanners in all possible sizes. Perfectionists are much more likely to be upset by warty Far Eastern machines than slobs who just see tools as a means to an end.

The acid test is rarely applied. Ask 1000 thousand Model Engineers to make a brass rod 9.7mm diameter and 30.1mm long. Half are far eastern, half are western. The rods are sent anonymously to a third party in an envelope identifying the machine used. The third party numbers the parts randomly, mixes them together and sends the boxful on to a team of judges.

The judges only have the parts to look at. They don't know who made them, or with what. The judges list which parts they think were made by Far Eastern and which by Western. The list is returned to the third party, who compare it with the truth. A chimp choosing randomly will get about 50% right, so only a much better match is significant. The degree to which judges do better than a chimp is a measure of how possible it is to tell the difference between the two types of machine.

This type of test is designed to thwart human bias, whether conscious and unconscious. It's completely fair. When applied, it often smashes belief systems, such as wine tasting experts really can tell the difference, and old violins are better than new ones.

If no-one can tell the difference between a rod made on a Myford Connoisseur and a Mini-lathe, then the Mini-lathe ain't so bad!

Actually there is a difference. Better made machines in good order tend to be smoother in action with more trustworthy positioning. They're easier and quicker to use, which is important when the workshop has to make a profit. Much less important to a hobbyist, who has time to coddle his machines, whether they be down-to-a-price Far Eastern, or clapped out Western antiques!

I have a WM18 mill that worked straight out of the box. Not perfect but close enough. I only had to tram it after deliberately tilting the head. I can think of several improvements but so far none of them have been worth my while. Other owners might insist on stripping the whole thing down and doing a careful rebuild. They're not wrong in that I'm sure it can be improved, but what arrived on a pallet is acceptable for what I do. It's not better than a Bridgeport and certainly not a tool-room jig-borer!

Dave

Cheers guys, I have adjusted the angle of the head and is now spot on as well.

So I may just leave the column

My problem is I have too much time on my hands

I shall clarify.

We shall have to agree to disagree on that point, Martin.

Regards,

Nigel B.

.

I suppose it depends upon how one interprets the word ‘should’

MichaelG.

Hi, well I'll not claim that my machines are exactly spot on as far as the head and spindle alignment goes, but I don't believe they are far enough out to be worried about. I did tram my Champion and mini mill up, using the same method as Zan, by using a brake disc, but I skimmed an old one up after removing the portion that fitted to the car. After skimming I did some tests to see if both sides were parallel to each other and to see if the thickness was consistent. My tests at the time showed a difference of about 0.0005" in just a small portion, which I accepted to be good enough. I've done a test to show how I decided upon the runout, which shows the result under two DTI's while rotating the disc through one complete turn. It might not be the most precise way, but the same result can be repeated time and again. The two DTI's are on the same radius and when they are both moved to an different identical radius, the DTI readouts are the same and in the same portion.

When I do any tramming with this, I usually rotate it on the table three or four times and recheck the results. I can't say that I've noticed anything really out to get worried about when I mill anything.

Regards Nick.

My mill is also "leaning" a bit as delivered, however it has two bolts you can force the head(Upwards) vertical using a measuring instrument as reference to check what you are doing. The distrubutersalesman was surprised to see it when I showed hin in person, seeing their latest ones and other does not have this ability of adjustment without adding shims(Resonable way of course). The additional question for me is why was it shipped this was, does tool pressure plays a role in decission-?

I did wonder about drilling and tapping 2 M6 bolts at the front of the column and using them to adjust

Don't, your next posting would be about the strange vibration you now have.

Ok OK I wont

The 2x bolts on my mill is in addittion, its not part of the setting or clamping surface where the shimming happens, so it should not interfere with the stiffness, most it should be checked at each height of operation of milling I would say.