Diogenes

It is clear from your opening post that you already understand the issue, but let me just reiterate:

The manufacturer’s approach is “if you can’t make it right, make it adjustable”

That’s fine in concept … but has clearly been badly executed !

Your best approach is therefore to do the same job, but do it better.

MichaelG.

I’ve often wondered how this is done in the factory.  I can’t imagine them fiddling with a DTI to tram the head as we do.

As assemblers are unlikely to be skilled, I guess the answer is a jig.   Something hefty that aligns the machine’s base and column so all the assembler has to do is tighten the bolts.  The jig might have a few built-in dials for fine adjustment.

The resulting alignment is ‘good enough’ provided the mill’s components are machined sufficiently accurately.  Several problems: if the machining is too crude, the head could move in transit or whilst cutting.  And if the mill is dismantled, we have to tram it the hard way without a jig with fiddly adjustments to a column that can move.  And those fine adjustments are made with crudely made nuts.  All a bit yuk.  Industrial mills are machined more accurately, but that adds hugely to the cost, putting new machines well beyond most Model Engineering budgets.

Can’t think of a way of extemporising a jig.  Too big, heavy and accurate to make in my little workshop.   And having made one, it would only get used once in a blue moon.   More practical to tram by fiddling and cursing for as long as it takes!

In 10 years I’ve trammed my mill 3 times.   Not because the factory setting is bad, but because the head can swivel on a bolt to cut at an angle, which is handy sometimes.  This is pretty crude, I think ‘too simple’.  It works, except putting the head back square is a pig.   Once, the thing went back in 10 minutes, but my last attempt took a day because it moved when the bolt was nipped up at the end.

Since been advised on the forum to do it by bringing the head flat down on the table, and then tightening up.  Not needed to try it yet, but should help considerably when the time comes.   Might even be how heads are aligned in the factory: the table is a flat reference. Wouldn’t be as quick as the jig I imagined above though, because a jig reduces freedom of movement much more.

Anyone know?

Dave

In my experience it’s rarely worth futzing around trying to get this sort of overly simplified adjustment feature to work properly once it has decided it’s not going to behave itself. Whether due to abuse, incorrect operation or just an unfavourable line up of the stars.

Generally such arrangements are due to the “How can we make it cheap enough for the customer to afford?” pressure remembering its not just one things its all the other details. Usual result its something that works on factory assembly and stands up to careful use by folk who understand exactly WTHIGO but once upset never recovers.

I’d bite the bullet.

Designate one of the lower studs as the master about which things pivot and arrange a shake fee fitting stud either by making new or fitting a bush.

Then fix two blocks carrying pushers to the back of the machine on a level with the upper studs. The pushers can be either screws or eccentrics on a pivot. Screws are perhaps more positive but can be a faff to get at round the back. As you only need a small amount of movement a simple short cylinder drilled perhaps 1/8″ – 3 or 4 mm off centre with a hex so it can be turned with a spanner would probably work fine as an eccentric pusher. Certainly the feel is better with an eccentric than with a screw.

Council of perfection is to use proper shoulder bolts for the bottom pivot and eccentric shafts but finding the right size may be unlikely. Easy enough to make something.

Authorities differ as to whether the master pivot bolt should be tightened down fully as part of the set up or whether it should be a shoulder style bolt permanently locked down and shimmed so things are stiff but just shiftable for adjustment.

Clive

For the benefit of future adventurers … Whilst the machine is still split [or is it too late to ask ?] could you please post some detail photographs of the existing ‘adjusters’

Thanks

MichaelG.

Please don’t disturb anything  now that you have it that close !

MichaelG.

Hi Howard Lewis, I have one or two, which I have used a few times.

The tallest two in the middle are 120mm high X 50mm in diameter.

Regards Nick.

On 10 March 2025 at 18:59 Nicholas Farr Said:

Hi Howard Lewis, I have one or two, which I have used a few times.

The tallest two in the middle are 120mm high X 50mm in diameter.

Regards Nick.

Hi Nick,

Can you give me a clue as to where I can obtain such an item please.

Regards

Gray,

Graham,

Almost any company rebuilding diesel engines of above 6 litres, (Lorry, tractor, generator, marine) will have pistons and gudgeon pins that are scrap, and would likely be prepared to donate one or two. If possible, choose carefully, unlikely to be worn or damaged, but major disasters do happen!

Howard