Putting right the bargain I bought

[Bogstandard]

A few of you may have read about the boring /facing head that I had bought

http://madmodder.net/index.php?topic=4418.0

Well it is now time to get it to a state where I can use it on my machine.

When you buy something for just over 20 squid, and the item most probably cost getting on towards a grand when new, you can't expect it to be in top notch condition. But actually, this one wasn't too bad. So this is my little escapade in getting it ready to be used on my latest project.


One of the missing items was the operating key, which is used to move the boring bar as the tool is spinning with the spindle. I have no idea what the original looked like, so I have made something that works.

Just a piece of 5.5mm silver steel with a 3mm silver steel cross handle. At the tip I rivetted in a safe breakaway, consisting of a piece of 3mm brass bar which was filed to shape to fit snuggly inside the key hole.




This is how it fitted.




The next missing pieces were one of the locking/friction blocks that act on the t-slots in the side of the moving block holding the boring bar.
The bearing block was soon knocked up and a bolt shortened to fit.




And again, this is how it fitted.




The next job was a rather major one. After removing the adaptor shell, I was left with a 3MT spindle. I could have used an MT to R8 adaptor, but I don't want to go that way, purely because it would lessen my working throat depth on the mill, and also it wouldn't be as rigid as I would have liked. So now it was time to turn the 3MT into a parallel spindle that would fit into an R8 collet.

I measured the depth of the plain portion in the collet, and transferred that depth onto the side of the taper. Measuring just on the line, I worked out the largest size of collet I could use to hold the head. In this case 7/8".




This is the setup that I used.
I bored out some soft jaws using two recesses. One to fit the OD of the head, and one inside that to clear some bolt heads that just protrude out of the face on the end of the head. You can see that better on the following picture.
Because there was just a bolt hole in the end of the MT taper, I fitted a screw tang into the end, just to give me a centre drilled support. The screw in tangs are available from Arc Euro. The bottom of this page.

http://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Lathe-Accessories/Tailstock-Accessories

This allowed me to support the end with a rotating centre.

I had to swing my topslide over by 20 degs to clear the tailstock, but the toolpost was exactly square to the centreline of the job.




This is a shot from the other end, and if you look carefully, you can just see the double recess in the soft jaws.




So I then took a roughing cut, but unfortunately I had forgotten to put in a marker where the spigot should end up, so I swapped the tool over and using a chamfer tool I put in a cut. This serves two purposes, the first being that there will already be a chamfer on the end of the spigot, and I will also know where to part off to, half way across the groove.




After putting my turning tool back in, I gently removed material until it was exactly on size.
It wasn't too difficult with a tipped tool, just a bit tough. The finish didn't end up super smooth.




But with the help of a tiny bit of emery cloth and fine wire wool, the finish was restored back to normal. The spindle ending up 2/10ths under size, perfect.




I parted off most of the way thru before taking out the centre tailstock support before finishing off. The end was then faced off.
Because of using the soft jaws, I had a fantastic grip on the part, and at a push, I could have done the whole lot without tailstock support, but I felt it was safer to use it.




The collet fitted perfectly.

Spigot end done!




I then fitted the correct boring bar I was going to use on the job.




It was then tried for fit and operation in the mill,

Just like a new 'un.

Job done.





All that needs to be done now is to make a removeable stop bar for the mill, and one for the boring head. Then I can get on with the flamelicker build.


Bogs

[madjackghengis]

Hi John, that's a right nice find you got there, and a bargain at that   Very fine log of the work needed, and a fine looking piece at the end of the job.   It reminds me how much I'd like to have my boring head a facing head as well.     cheers, jack

[kwackers]

That's a nice boring head.

I'm currently looking for a decent boring head (with MT3 taper!) I've a Soba one which imo is rubbish, it's impossible to lock up the dovetail tight enough to do a decent cut.

[arnoldb]

Very nice indeed John 

I would have balked at trying to machine that morse taper down; from some personal escapades I know that they are usually hardened; HSS doesn't touch them.

If you happen to take the head apart one day to clean/lube it inside, some photos would be greatly appreciated.  I can't get my head around how they work internally.  It seems as if there must be a lot of delicate internals, and yet it must be robust enough to handle the forces involved in boring and facing operations.

Kind regards, Arnold

[shoey51]

Im not sure how that thing works but Ill keep watching and hopefully you will reveal the secrets.
great work as usual Bogs

[Bogstandard]

I have no qualms about using second or even tenth hand bits of tooling.

If they can be made to work cheaply, like this one, it puts very expensive tooling, which I couldn't possibly justify being spent for use in my amateur workshop, into my grubby hands.

I can honestly say that my precision cupboard has had very little cash outlay on my part, but there must be many tens of thousands of pounds worth of tooling in there. Most of it donated by no longer with us engineers or my seaching about and picking up bargains like this one.

Ten or twenty squid spent on a bit of tooling that you will hardly ever use will become a great investment for when the time arises when you can't do a job without it, plus if needs be, it can always be sold for more than you paid for it.

If I think that one day I might be able to use it, and it is not a lot of money, then I will buy it.

If I don't get to use it, then someone I know most probably will.


Arnold,

I was going to do a deep strip on it this time around, but thought better of it. Needs for use come first.

As and when I feel up to it, I will get it done and catalogue my progress.

Actually Shoey, unlike a normal boring bar, where you have to stop the machine to put another cut on, because the centre portion is held static by a bar sticking out of the side, you put the cut on while the machine is still in motion.
Not such a big thing while boring, as you would need to stop so that you can measure up the bore, but the main advantage is when you come to the facing part. You can put an outside face on the job that is perfectly square to the bore, just by turning the key and bringing the tool out as far as you want the face to be.
That saves a second operation, where you would normally either transfer the job onto the lathe or RT to carry out that facing bit. With this bit of kit, you do it all in one.

I hope that has explained it OK.


John

[Rob.Wilson]

Nice one John ,,, i am pleased you got one for a good price 


Handy it of kit when the need arises 

Rob

[Bogstandard]

Thanks Rob, it came at the right time.

Whenever I came to use a tool that required a rotating portion to be stopped, my coaxial thingymajig DTI or my power tapping head, and now this, I would either use my hand or a rigged up mag base to do it. I have now decided to make something a little more permanent, and have it fitted to the mill all the time.

So this is what I came up with. A few bits from the junk box and a few bits of metal and fixings from stock.
The black plastic knobs came from somewhere many years ago, and it was time for them to earn their living. The brass faced grub screws will give a good grip without doiing too much damage.
There are two holes for the 1/4" rod. At the moment it is in the stored position, when moved to the vertical hole, it is ready to use.




This is where it is fitted on my machine. Not in the way of anyone or anything until it is required for action.




The head needed a stop bar as that was missing, so I made one up out of bits of stainless, it has it's own locking collar that locks up the thread to stop it rotating out of the hole.




After shortening the stop bar to the correct length sticking out of the side of the boring head, and putting the vertical stop rod into it's operating position, I then turned the spindle to rotate and took a couple of shots, hopefully to show how the centre barrel is stationary while the spindle and boring bar are rotating. You can now realise that if I turn the key, I have control of the boring bar tip position while the head is turning.







NOW things are ready for carrying on with the licker build.



Bogs