Adjusting heavy milling head to an angle. Dealing with weight.

[TR]

I have a mill drill which allows the head to be adjusted. There are three bolts which hold the head in place. Now the motor and gearbox are incorporated in the head. Makes it very heavy. I find it could be dangerous tilting the head to say 30% because it could fall to one side and cause damage. Do machinist actually adjust the head to other angles ? Are there techniques one would use ?

This is my mill drill from a few years ago.

[Mcgyver]

It may not be that bad. To some extent its counter balanced. my XLO has a worm and wheel but you still want to take most of the weight by hand....as well you don't want to rely on the worm; ie something could break/be broken. So even on a full sized one, where it isn't that well balanced, its no big deal to take the weight over to say 45 degrees which I can do on single handed. One hand on the head, one on the crank.

A better procedure is to have two people; one to bolt and one to spot.

[bborr01]

TR,

Most of the
Bridgeports and clones have a worm gear for adjusting the head tilt or nod. I don't know how you would control the tilt on a machine like yours.

Brian

[wierdscience]

Simple solution for tilting the head safely is a small block and tackle between the top of the motor and ceiling.A 2 or 3 sheave block will give you good control add a small handcrank winch if you want positive positioning capability.Something like a commercial window blind winch would handle it along with the blocks.

http://www.na.lv/eng/sale/?c=154&p=382

[Dunc]

I have a much smaller mill but the advice I received (believe it was on this forum tho I can't quickly retrieve the post) was to avoid tilting the head and tilt the work instead. Saves all the hassle of re-tramming every time the head is offset.

[loply]

I've got more or less the same machine.

I've tilted the head several times, if you don't slacken the bolts off too much it's really not dangerous. It's actually quite hard to move the head.

To get it back in tram I would suggest making two brackets like these -> http://bbs.homeshopmachinist.net/sho...598#post761598

At least, if the bore betwixt head and saddle on yours is as bad as mine, you'll need them.

Cheers,
Rich

[Black_Moons]

I've got more or less the same machine.

I've tilted the head several times, if you don't slacken the bolts off too much it's really not dangerous. It's actually quite hard to move the head.

To get it back in tram I would suggest making two brackets like these -> http://bbs.homeshopmachinist.net/sho...598#post761598

At least, if the bore betwixt head and saddle on yours is as bad as mine, you'll need them.

Cheers,
Rich

Agreed, those heads don't move easy.. rather.. well bound, since most of the weight cocks the t nuts and such.
I loose my mine slightly then have to hit it with a huge dead blow rubber hammer to move it any... For precision adjustment (traming) I tighten the bolts slightly and hit it even harder.

[Mcgyver]

I have a much smaller mill but the advice I received (believe it was on this forum tho I can't quickly retrieve the post) was to avoid tilting the head and tilt the work instead. Saves all the hassle of re-tramming every time the head is offset.

of course there's always the "it depends".....but I disagree with this advice in principal in that tramming the mill head is part of good workmanship. Its not a one time thing; the mill head goes out of tram with use and needs to be resent periodically....an approach to working that avoids tramming isn't a good approach. if the work is very light it won't matter, but in general its often a more solid set up tilting the head and isn't required that often ....the mill head tramming gets done more often than head tilting (at least thats been my experience)

[LKeithR]

of course there's always the "it depends".....but I disagree with this advice in principal in that tramming the mill head is part of good workmanship. Its not a one time thing; the mill head goes out of tram with use and needs to be resent periodically....an approach to working that avoids tramming isn't a good approach. if the work is very light it won't matter, but in general its often a more solid set up tilting the head and isn't required that often ....the mill head tramming gets done more often than head tilting (at least thats been my experience)

Have to agree here. When I first started using a mill--years ago--I avoided tilting or nodding the head and had some real fights with awkward setups. I got to watching and talking with a couple of old hand machinists at other shops and soon realized that they seldom hesitated to move the head if necessary. Get the work mounted solidly on the table and then bring the tool into alignment was their motto. The trick is to "practice" tramming the head so it becomes second nature; so you know almost instinctively where to make the adjustments and how much the head moves when you do the final tightening of the bolts. It helps to have proper tools, too. Although I get by fine with a single dial indicator on a bent rod one of those "two-headed" devices works a charm. I don't own one but I've played with a borrowed tool and I really have to get busy and build myself one. One of those with a little trig would also make it a snap when you're setting up to take an angled cut...

[willmac]

...an approach to working that avoids tramming isn't a good approach.

This is very good advice. In fact it is more than that - if you don't check tram regularly you will eventually regret it with a vengeance. I once spent about 5 days machining two matched parts in some expensive Aluminum alloy. They were machined practically all over, had many tapped holes and two large bores. I made the bores first without any problem, exactly to size and was very pleased with myself. It was only when I had finished the parts and tried to assemble them with other parts that I found that the bores were not quite square, and for this job they had to be very close. The parts were scrap - and I still have them as reminders to myself - always check tram before boring.

[SGW]

I don't have the same milling machine but mine has the same problem. Loosen the 3 bolts and no end of excitement is just waiting to happen. I find that if I loosen two of the bolts so they are not binding anymore, then stand on the side the head is going to be tilting toward and carefully loosen the 3rd bolt just enough so the head will move with some effort, keeping the wrench on the bolt in the process for instant snugging-up if necessary, I've managed not to kill or maim myself yet.

Another trick I've used for "large" tilts approaching 45 degrees is to tilt the head until I get nervous (maybe 30 degrees), then put a wood block between the side of the head and the table so the head can be tilted in a controlled way by lowering the knee. Since the block's contact point on the side of the head will move in an arc, this stunt takes judicious observation and re-adjustment while you're doing it.

[mike4]

As was stated earlier , its no big deal to tilt the head for some setups as it can be safer than some weird hold down setup.
When the job is completed part of the next setup automatically is check the tram and make sure that any other adjustments were returned to normal as well .
its all part of the job.
Michael

[TR]

I've got more or less the same machine.

I've tilted the head several times, if you don't slacken the bolts off too much it's really not dangerous. It's actually quite hard to move the head.

To get it back in tram I would suggest making two brackets like these -> http://bbs.homeshopmachinist.net/sho...598#post761598

At least, if the bore betwixt head and saddle on yours is as bad as mine, you'll need them.

Cheers,
Rich

Rich, I like your brackets. I will try the brackets.
Good advice Guys. Thank you.
I do not post many questions, but seem to solicit good discussions. This is why I always return.

[dave5605]

Keith mentioned using the dual dial teaming device with trig to set the head on an angle. Not sure how that would work, other thsn fir a very shallow angle, but you can use the dual dial trimmer with a sine plate to set a precise angle. Just set your angle in the sine plate and adjust the mill head till both dials on the team met read the same when against the sine plate. Not my idea. I saw it on one of the websites selling the two dial trimming device.

[GNM109]

I move the head on my Webb mill when required and always re-tram afterwards. I'm careful to support the head when moving so as to take the load off of the worm gear in the center of rotation or for nodding. Also, when I return the head to its vertical position, I don't use the worm by itself to do the raising. I keep upward pressure on the head while turning the worm drive shaft in order to relieve strain on the worm gear. I had the head off of the mill when I was refurbishing it and those gears don't appear to be all that sturdy.

I've read about broken worm drives on Bridgeport and similar mills apparently from using the gears alone to do the lifting.