Boring head won't fit (but not for long)

[Bogstandard]

I've been searching for a second hand boring and facing head for a while now, but haven't been able to find one cheap enough, so last week, I treated myself to a metric boring head, but a small one, 40mm diameter. I have plans for it, so I didn't want a 50mm one to match my Imperial boring head


The problem is that although it comes with an MT2, MT3 & parallel shanks, I use R8 on my mill. So at the same time, I bought a blank R8 arbor.
So this post is just to show the unitiated how I go about machining it up to fit.




The R8 arbor is a little difficult to hold rigid enough in a lathe chuck, and because it already had a centre drilled into the end, I set it up between my chuck and a live centre.




It was soon down to rough size, but because I was getting tight on the live centre, I swapped it for the old standby, a solid half centre with some grease on the end. This allowed me to get real close up




I had already measured the thread required, it was 14mm x 1mm pitch, a thread size that is being used in a few bits of tooling nowadays. So the thread spigot was turned to size, a thread runout slot cut just a little deeper than the thread depth, and the lead in taper put on the end.




It only took a couple of minutes to cut the thread once I had swapped over one change gear, and slipped the selectors into their correct positions. The swing up threading tool did it's great job, just like normal.




The new head fitted really smoothly.




So now I have the set of mandrels so that the head can be used on any of my machines, but I have now got to go find it a home in one of my racks, as it now won't fit back in the box it came in.




A nice easy job to do on a quiet Sunday morning, now I can get stuck into the Minimag build.


Bogs

[ieezitin]

Nice job john on showing people that they sell soft blanks for just requirements like you have, for people who would have a bane of a time in tapering this is just the out.

BTW what’s the doodad on top of the tailstock?

Anthony.

[trevoratxtal]

Many thanks Bogs.
Great photos, it says it all to me.
Trev

 

[John Rudd]

Nice job john on showing people that they sell soft blanks for just requirements like you have, for people who would have a bane of a time in tapering this is just the out.

BTW what’s the doodad on top of the tailstock?

Anthony.

Another of Bog's mods...Its a linear indicator/digital readout or whatever you wanna call it...
I think I'm right aren't I...?

[Bogstandard]

Anthony,

John has it spot on, but as I don't have any long shot pics to hand, but if you go to the last bit of this message, it shows my read head setup for my DRO on the tailstock.

http://madmodder.net/index.php?topic=1938.msg20484#msg20484

BTW, I always have MT blank ends in stock, just stick them up the spindle spout and machine the ends to whatever you want to do, it is amazing what sorts of little tools you can come up with to make life a little easier. The R8 ones are a little more difficult to hold, but as I have shown, perfectly doable.


Bogs

[arnoldb]

Thanks for showing Bogs  - great post as always.

Its interesting to note that your boring head appears to have a .75mm pitch lead screw...  I was wondering about that when I built mine; 1mm pitch would have been too coarse, so I settled on .5mm for "easy" size calculations as 1 full turn makes a hole 1mm bigger.  My second option back then was to go for an M5x.75 lead screw.

Thanks for the heads-up on the M14x1 as well; when I build more tooling in that range it's good to know that that specific thread is getting regular use.  I'm trying to get away from using "whatever happens to be convenient" thread sizes.  With a bit of standardisation, things gets easier in the long term.

And that swing-up tool holder is still a definite to-build on my list 

Kind regards, Arnold

[Bogstandard]

Arnold,

I am a little perplexed over the leadscrew as well. As you say, a pitch of 0.75mm, each division (50 off) actually gives a movement of 0.015mm. I haven't tried it yet, but my Imperial one enlarges the bore by 0.001" for each division, I am expecting this one to enlarge it by 0.03mm, so not as accurate as the old one.

I have noticed, even over the last few weeks, 14x1 is a standard sort of size. My RT that I modded a few weeks back is over 25 years old and that had it on there, and a lot of the watchmakers chucks and holders use it as well. If I am going to be doing a lot more small tooling I just might invest in a set of taps and dies. I am a great believer in having standardised tooling that fits other things.

In all honesty Arnold, I think that swing up threader has to be one of the best tools I have ever made, it makes single point screwcutting a joy to do, but your lathe must have a reversing chuck and leadscrew.
I have already thought up a fairly easy design for one that does internal screwcutting, but at the moment, I just don't have the time available to develop it.


John

[krv3000]

well dun bogs   

[Rob.Wilson]

Hi John


Nice mod ,,   ,,,, i have the same boring head set ,,, not a bad bit of kit for the price     


rOB

[Bogstandard]

Rob,

The reason I went for this one is that I am thinking of boring the cylinder for the R&B on my mill, horizontally, and this will go into the bore, allowing a shorter boring bar, whereas with the 2" one, I would have to use a bar as long as the bore.

Just an idea I had, it won't be started for a while yet.


John

[Dean W]

Nicely done and shown, John.  Straightforward instruction and good pictures, as usual.
Thanks for sharing.

Dean

[Rob.Wilson]

Rob,

The reason I went for this one is that I am thinking of boring the cylinder for the R&B on my mill, horizontally, and this will go into the bore, allowing a shorter boring bar, whereas with the 2" one, I would have to use a bar as long as the bore.

Just an idea I had, it won't be started for a while yet.


John

Hi John

Very cunning plan you have there 

I used mine to do the boring on the side of the R&B casting



Rob

[Ned Ludd]

Hi Bogs,
Is there a reason you did not want to use the parallel shank, from the set, in an R8 collet? I have to admit that I would be tempted, just to save the odd inch of vertical height under the quill, but then I am always looking for an extra inch.
Ned

[JimM]

Thanks for the post Bogs

Although not particularly relevant to anything I need to do (at the moment) just the pics showing the machining has taught me a new trick. I would never have thought to have the tooling on the right hand side of the toolpost, instead I would have mounted it in the normal way and struggled to fit everything in the restricted space around the tailstock 

Guess it's another one of those things that are obvious when you see it in practice and comes naturally to experienced machinists but are like a flash of inspiration to the newbies

Jim

[75Plus]

Hi Bogs,
Is there a reason you did not want to use the parallel shank, from the set, in an R8 collet? I have to admit that I would be tempted, just to save the odd inch of vertical height under the quill.
Ned

I had the same thought. As I looked at the kit I saw arbors for 2MT, 3MT and a UNIVERSAL arbor which would adapt to ANY taper system using collets.

Joe

[stefang]

Nice Job on the R8 shank

I am a little perplexed over the leadscrew as well. As you say, a pitch of 0.75mm, each division (50 off) actually gives a movement of 0.015mm.

I got the same boring head from chronos.ltd.uk, and with the 0,75mm pitch it is very arkward to work with, so I got myself threading tools (In and out) for a M6x0,5mm thread.
My plan is to bore out the old M6x0,75 thread (Got a second, smaller 25mm boring head) in the head and insert a bronce nut with the new thread (and, of course, make a new leadscrew).

Should be a job for a rainy sunday afternoon

Stefan

[Bogstandard]

Ned & Joe,

There is method in my madness, as I explained to Rob.

Normally, as you say, I would have used the parallel shank. But a little later, I will actually need to bore some holes deeper than the actual head and cutting tool, in fact, I might even need to add an extension piece between the new arbor and the head.

I am looking to do it this way as it will be a much more rigid setup than if I used a longer boring bar.

This is all because I cannot stand up at my lathe for long to do the setup for between centres boring, I would be trying to set it up for hours, standing for a couple of minutes, resting for half an hour, whereas, I can do the whole lot at my mill whilst sitting down.

Sorry for any confusion.


Jim,

I am glad that you managed to pick up a bit of a techinque or method from my post, that is why I take so many pictures of the setups, just to show people how I do it.

Experience is only based how many tips and techniques you can pick up and mentally retain over the years, plus a little bit of your own thinking as well.

John

[75Plus]

Ned & Joe,

There is method in my madness, as I explained to Rob.

Normally, as you say, I would have used the parallel shank. But a little later, I will actually need to bore some holes deeper than the actual head and cutting tool, in fact, I might even need to add an extension piece between the new arbor and the head.

John

Makes perfect sense John, I suspected that you had a very good reason for it. I should have picked up on it in the first post as you gave your reasons for obtaining the 40mm size.

Joe

[Ned Ludd]

I too had every faith that there would be a good reason, I just wanted to know what it was.
Ned

[J Harp]

Another fine project Bogs. Since the swing up threading tool project anything with Bogs name on it is a must read for me.
Jim