Getting the mill add on just right

[bogstandard]

This is a follow on from my post about the horizontal arbor I aquired a few days ago.

http://madmodder.net/index.php?topic=2058.0

Luckily for me, I have a few days to myself, so I thought I would get this out of the way first, before going back to my RT chuck holder.


So to get started, out came my notebook and a few measuring tools. This doesn't need to be a super accurate job except for the angle settings, they have to be spot on. Everything else will be made to split the line where marked. The casting isn't all that accurate on the outside, so things will have to be made to fit in places.

I am doing my little trick that I do with most things like this. The original equipment will not be touched, so I can revert back exactly to what it was before I started if needed.




The first thing to do was to accurately check the angles on the two mismatched parts. It turns out that the new bit is 50 degrees, and my machine is 55 degs. I quoted them as 55 & 60 in my other post, and that has now been corrected.




I searched all over my stock to find a piece of material to do the job and this is what I ended up with. It is not brass but some harder material, I suspect one of the bronze range. In fact it is a little short on height for the job, but that will not be critical in the long run.




The metal got a dose of side and face cutter, and was soon into the two bits I needed.




The two rough pieces look like that they will be plenty high enough, but once they have been dropped to the correct angle and had the locating faces machined, they will definitely be short.




So both pieces were fly cut all over, and they were brought into being perfectly square and parallel on all faces.




Now the parts were at a stage where they could be fairly accurately worked on, the retention faces were marked up and the first one was mounted in the vice.




My cheapo angle gauge was zeroed up on the table.




Then the block was set to the required 50 degrees. This is where squareness comes into it's own. If the sides were not parallel and square, the part could not accurately be mounted the way it is, it would be liable to be out of square to the vice fixed jaw.




I then machined downwards and sideways until I split my marked up lines.




Before it was removed from the chuck, it was checked to make sure it hadn't moved during the heavy machining. It was then stood upright, and the very sharp angled corner was flatted down slightly so that it would fit right into the corner on the casting machined angle.




A perfect fit.




The same crossways as well.




So what I will do for next time is get the other one to the same stage, then I should be able to cut the second angle.



Bogs

[Stilldrillin]

You`ve got the project nicely under way, and clearly shown John! 

David D

[Bourne Bill]

Hello Bogs, how do you like that angle finder?

[bogstandard]

For the cost (about 20 squid) they are a wonderful bit of kit compared to the older precision instrument methods of doing it, but not as accurate when going into really fine settings, then I would have used a sine bar and slips, but for everyday use and brain switched off measuring, they are perfect.

A useful addition to your arsenal.

Now if they could only get the magnets to work on ali and brass.


Bogs

[RobWilson]

Hi Bogs

very nice looking mill attachment,,i would not be without my HZ/V mill ,,,,, after seeing your mill i now have machine envey 

Regards Rob

[bogstandard]

Rob,

It is about the cheapest and smallest of the Bridgy clones, Chinese of course. I couldn't fit a full sized one in my shop.

But I have had it just over a year, and have yet to find anything bad to say about it, only that I love it more than my Chinese lathe, but it is a damned close contest.

You wouldn't have caught me saying that a couple of years ago, but in all honesty, I took the plunge, and have never regretted buying far eastern machinery, both are great machines.


Bogs

[DICKEYBIRD]

I just got one of these and it works great so far.  The 1st one was a dud and I had to send it back.  The 2nd one is fine.  They paid shipping both ways.

I later found out they have them in the local store and I could have used the 20% coupon.  Dangit! 

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95998

[Bernd]

Do they make one for brass and aluminum? 

I need to get one too. Sure would beat a sign bar.

Bernd

[bogstandard]

Getting my own back now for the wooden engine fiasco.

Now if they could only get the magnets to work on ali and brass.

That was from a post of mine a couple of days ago.

What's wrong Bernd, given up on reading, and only looking at the piccies? 

BTW, I was due to finish this post off last night, but a flat tyre on the passion wagon put paid to that. After struggling for well over an hour to change the flat (only on the bottom).

Me laying on the ground controlling the jack and wheelnuts, grandson on the standing up bits, and the torch, with Bandit going ballistic all over the place, all because he has a great fetish for chasing torch beams and reflections. We must have looked like a real weird bunch. Thank goodness it was in my own driveway and not somewhere more public.

I didn't feel much like going in the shop after that. Out this morning to find a replacement tyre (tire, just for you colonials).


Bogs

[Bernd]

What's wrong Bernd, given up on reading, and only looking at the piccies? 

Bogs

Owwww caught me again. Can't get away with nothing.   

Bernd

[bogstandard]

I just wish I could have got onto this a lot sooner, but anyway, I managed to squeeze in a couple of hours this evening to try to get this project on the road again.


Continuing on from the last post about machining the blocks, I got the second one made, just like the first. As you can see, the blocks self support because they lock into the dovetail system, so there will be no need for me to fix these to the main casting to keep them in a working position.
I have already mounted the casting onto the table, and clocked all over the two top faces, and it is perfect for alignment, except for the front corner of the RH face, for some reason, that area has a slight dip in it, not a lot, but enough to cause me a little concern.




I need to lock the new gibs in position so that they can be machined, so a little bit of 6mm threaded rod, a nut and a bit of bar with a 6mm hole drilled half way down it. The ends of the rod and bar had a rough 90 degree angle filed onto the end of them. These bits took no longer than 10 mins to make.




The next two pics show just how this jacking piece works, and work it certainly did. The two gibs were locked in solid.







I flycut the gibs down and the final operation was to take a couple of thou skim off the top faces of the casting and the gibs together.




The finished result. In fact the surface finish on the casting is better than the original.
You can just see the problem area on the right. It turned out to be a chilled area on the casting, and so much harder than the rest, but on rechecking, everything was now level, just that area has a slightly different surface finish. I could have mounted it onto the surface grinder, then the whole lot would have a regular finish, but I decided that what I had was perfectly good enough.




The gibs were now set up for final finishing.
The flycutter with a round nose does a great job of mass material removal, and still leaves a very acceptable surface finish behind. This was taking off 2.5mm (0.100") in one cut.




A little bit more trimming up.




The gibs are now finished except for having the angled face machined on. This will require a slick bit of measuring on my part, so I have decided to leave it until tomorrow (later today).



It is now time for me to settle down with an a**e ripping takeaway curry, and a good sci-fi flim.

See you tomorrow later.


Bogs

[Darren]

Very informative as ever John..

And looks good .... 

[dsquire]

Very nice John. Like the way you made and used the jack. 

Cheers 

Don

[bogstandard]

This, at last, is the final part. I got into the shop today and finished off what I should have done last night.


The gib sides at this time are still parallel, so I did some fine measuring up on both the machine and gibs, and found out how much metal needed to be removed.
Because there were 5 degrees difference between the machine and the arbor casting dovetails, the gibs were set up at 5 degrees.




After a few minutes work, the metal was gone. The other gib had the same done to it, and then they were both cleaned up and deburred.
Time to see if I had got things right.




This side seems to have matched up Ok.




And so does this one.
In fact this one looks rather odd. That is because this one side contains a moveable clamp (the big round bit in the middle of the end) and the gib doesn't actually rest on the main casting but a dovetail on the end of the clamp. I cut the jibs to a thickness to allow a 1/8" movement on the clamp before everything locked up solid, hence the 1/8" gap you see between the casting and new gib.




The full Monty.
I am really pleased that everything worked out as planned and the unit is very rigid and well supported.
The bottom small casting will be removed and stored in the box with the right angled head, the main bit of this casting will stay in position on the machine, it will not come to any harm and isn't in the way of anything, plus I won't have to find somewhere safe to store it away.



So now for a change.

For the last few months, I haven't had my better half to help me clean out my shop, which she used to do regularly every week for me.

I am absolutely disgusted at the state of the floor in my shop, even Stew offered to clean it out for me when he called today. But being as I am, I politely refused.

So starting tomorrow, I am having a good dig out and clean up, if the body can take it. It might have to be done over a couple of days.

Only then will I decide what the next project will be.


Bogs

[Bernd]

Bog's

Nice job as always. But am I missing something here. Those plates look awful thick. It looks like the distance on the dove tails on the arbor are further apart than the dove tails on the machine. Am I making any sense here? Do you understand what I'm asking?

Also how come you ued an end mill to cut on that last cut instead of a flycutter? To much material to remove?

Regards,
Bernd

[AdeV]

Bogs:

 

As a newcomer to machining, I'm pretty much hanging on your every word, as these are all really interesting techniques and tricks your showing. Kudos. I sometimes have trouble keeping up with you, luckily not this time 

Bernd asks why you use an end mill - same question, but also, any particular reason you milled on the X-axis? I'd have thought the Y axis would have needed fewer passes & hence been slightly quicker?

[bogstandard]

I knew that this would come up and bite me on the bum.

It is all because I was in a rush and in bone idle mode.

My tram is very slightly out, and at this late stage of the game, I just didn't have the heart to have a good clean down and retram the head.

I will try to explain why I went the route I did.

Normally, when your tram is spot on, you will have no problems at all, and you would be able to use a flycutter to get a perfectly flat face.

But even with the tram being a minute amount out, you cannot get a perfectly flat surface in the X axis or an accurate angle cut in the Y.

So I used a normal end mill to give me what is in effect a flat surface made up of a series of ridges.

I have done a couple of C-o-C's to explain why I went the route I did.

I showed this the other day in a post about a problem someone was having. Showing what is happening when the tram of your machine is out in the X axis. Most people won't have the facility to tram in the Y axis.




These are the exaggerated effects of using a flycutter when the tram is out.




This is how you can simulate a flat surface by using a series of cuts with a smaller cutter. The top faces of the ridges form a very good approximation of a flat surface.



Don't let these pictures scare you into thinking that just a small bit out of tram is going to cause major problems. If the tram is out say by a couple of thou, the 'dishing' effect is minute.

The reason I have shown all this is that it could, under certain conditions, cause head scratching problems, and if you are aware of it, it can be allowed for.

There is a moral to all this.

Keep your tram spot on, and don't get caught using an out of tram machine.


Head bowed in shame Bogs.

[bogstandard]

And now to answer Bernd's question.

If you have a look at the dovetail pictures in this post

http://madmodder.net/index.php?topic=2058.0

It showed the right hand dovetail in full contact with the top face and the left hand one just about on there, but still safe.

The reason for the thick gibs was twofold,  correct the out of angle, but also to move the RH casting dovetail across some, so allowing more contact on the LH one. In fact they are now sitting equally on either side of the machine dovetail.

I hope this has explained sufficiently.


Bogs

[Bernd]

Bog's

Ok, I understand your use of an endmill there. Makes perfect sense. And you don't have to hang your head inshame. We now know the reason why it was done.

I thought I had seen pictures of you showing the unit mounted. I thought it was in this thread. Now fully understand why they are that thick. I had thought I'd seen pics of a much closer fit, but my old mind is palying tricks on me.

Thanks for the nice explanation.

Now get that shop cleaned up and let us see what your next project is going to be. 

Bernd

[bogstandard]

Thanks Berndt.

I forgot to answer this

I'd have thought the Y axis would have needed fewer passes & hence been slightly quicker?

You are quite correct, it would have been slightly quicker, but exactly the same surface area needed to be cut. I have a tendency to cut from right to left. It is just a thing I do, and by doing it the same most of the time, I don't fall into the climb milling trap. I start at the far side and work towards myself.

I then don't overtax my brain cell too much, one less thing to worry about.


Bogs

[AdeV]

I'd have thought the Y axis would have needed fewer passes & hence been slightly quicker?

You are quite correct, it would have been slightly quicker, but exactly the same surface area needed to be cut. I have a tendency to cut from right to left. It is just a thing I do, and by doing it the same most of the time, I don't fall into the climb milling trap. I start at the far side and work towards myself.

I then don't overtax my brain cell too much, one less thing to worry about.

A perfectly reasonable explanation; I too have issues with a misfiring brain cell... I also have a problem with the Y-axis of my mill vibrating (like a resonance thing, it's a bit wierd) when the saddle is moving backwards towards the column; so I too tend to mill on the X-axis. Except when I forget...

[NickG]

John,

Kept having to mark this thread as unread but have just had a read through and found it very enjoyable. Could do with one of those digital angle gauge thingies. How do you ensure it's parallel to your work piece? Just align the front edge as best you can? Also, when you clamp things in the vice at an angle like you did, do you put any packing underneath or just clamp it tight and take light cuts? I know you didn't take light cuts though 

Cheers,

Nick

[Gerhard Olivier]

Had to go look at the first pic again to understand this one -now it makes sense

Nice post thanks

Gerhard

[bogstandard]

Ade,

That Y axis problem sounds like a locking up gib strip, it might be, if you have tapered gibs, the gib isn't locked in position by both end screws, allowing it to slide backwards and forwards, so it locks up one way then releases the other. Or it just might be a bit of metal in the gib area or just lack of lubrication.

Nick,

I wouldn't totally rely on one of those angle gauges, but I just do the squaring up by eye. Aligning one of it's edges with say an edge of the job or machine vice jaw, there is always somewhere square you can eyeball along. But I did mention that they are no use for short jobs as they are, because of the foot shape, it isn't flat, so I stick it on a parallel and use that as the datum foot, as I showed in one or two of the shots.

Because the piece I was machining was a big lump, and it was at an angle, I could only get a corner touching the parallels. That told me I was level in the Y axis. Because I was using a 16mm tungsten end mill, my depth on the first cuts were about 6mm deep by about 10 mm wide, only when I get close do I use fine cuts.

But you must remember, I have beefy machinery and a big grip on the vice, for normal small mills, those sorts of figures would be way over the top. But a lot of home machinists really do take too long in removing metal. In fact that can cause real problems at times when cutting materials such as bronze, stainless and high carbons. Sometimes just skimming the surface can cause the material to work harden instantly, and no amount of trying will get you thru the hard skin that they produce. That is when brute force comes in.

If you are brought up only doing machining at home, you tend to just tickle the metal because you are scared of it, and everyone tells you that you shouldn't take large cuts because it will do damage to your machine. The machine, metal and tooling will soon tell you if you are working it too hard, so you stay just below that threshold.

Out in the big world, what I am doing is mini machining, the big boys get the excess stuff off as fast as they can, time is money. That is why you can use one tungsten tip for weeks or months on end, whereas they will get thru them at maybe a dozen or more a day. In fact, at such a rate, some factories have dispensers like Coke machines, put the job number in and it will give you a load of tips for the job. The tip man comes round every so often and fills it up, makes a note of how many have been used, and then bills the company.

We are only playing at it.

Bogs

[NickG]

Thanks for the info John. I don't think I've ever had to seriously drill or mill anything on an angle yet! I've probably chosen designs where I don't need to. I always thought I'd definitely have to get a milling machine with a tilting head but that never seems to be the preferred method, suppose you have to fart on re-tramming the mill afterwards - although you don't with your device 

I am starting to get a bit more confident, taking heavier cuts, especially now I have a much heavier lathe and milling machine. That's the surprising thing, often a better finish and less noise and vibration is obtained when the cutter is given something to do. I am sometimes falling foul of inaccurate dials / backlash / human error in calculations though. The way I am trying to do things is once I have a clean concentric cut on something, measure it with the digi calipers then work out what needs removing. I'll maybe leave 10thou for finishing cuts and break the bit to be removed up into chunks. On the pistons I am about to show in my flame gulper thread I was taking 40thou roughing cuts which was quite a lot for me - I should probably take more. This is where DRO's definitely come into their own. When I can afford it, I think i may go down that route as it would transform my machines.

I know what you mean about the big boys, we have those tool tip dispensing machines at work.

I have always been told the bigger the machinery the better. When I asked advice at our club it was to buy machinery as big as your budget and space allows. A big lathe can machine anything a small lathe can but not vice versa! It took me a while to believe this but I definitely believe now!

Nick