Author Topic: Peter E - Light Duty Live Center w Changeable Tips  (Read 14547 times)

Offline PeterE

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Peter E - Light Duty Live Center w Changeable Tips
« on: June 24, 2012, 08:38:23 AM »
Some time ago I posed a question about fit for needle roller thrust bearings. I got very useful info, and my intended target was this light duty live center with exchangeable tips.



It was in this thread: http://madmodder.net/index.php?topic=7054.0

So at last, a day when I could get into the shop to continue with the light duty live center, my version with exchangeable tips. The idea originally came from the book about Unimat 3 lathe accessories by Bob Loader. I made the accessories for my MJ-189 (which I stll have) and found them to be very useful every so often. So useful that I wanted the same stuff for my C3.

But as in many cases you have to make something else to be able to start on what you had in mind ...  :bang:  So I had to make a drawbar for the lathe to be sure that the MK tooling in the spindel stayed there. A drawbar is nothing complicated, it only takes some time, and out of the machine came the following contraption.



A brass bar with an M10x1.5 thread in one end, and an M12x1 thread in the other. The M10 end was for the MK tooling end. As a "nut" I made a sleeve with a close fit in the spindel in one end, supported by a shoulder to act as a stop when tightening, and a handwheel in the other end. All made from brass bits form the scrap box.

The C3 have an MT3 taper in the spindle and as the item I made would have an MT2 for the tailstock I used an MT3 to MT2 sleeve with a nut. This nut makes it possible to release both the MT2 part from the sleeve and sleeve itself from the spindle without having to bang in the axial direction, something I avoid to keep the bearings in shape.



The whole setup looks something like this when out from the lathe. Actually very good and solid during work.



The handle end is made so that the end cover can be kept in place during work. It becomes much tidier then.



OK, so now it is possible to start with the real job. I used a ready-made blank end arbor as I have not made myself a taper turning attachment yet. As can be seen, I took down the outer diameter fom 40 mm to about 30mm and then made a hole for the needle roller thrust bearing I had (21x4x8 mm).



The hole was made 25 mm deep, the bearing used 4 so the plain bearing sleeve to in to the hole should be 20 mm deep to avoid locking the bearing. Still the outer bearing ring missing in the picture.
 


The sleeve has a small shoulder and is made to a close but still easy and wggle-free fit in the housing. When all parts were assembled I drilled a crosshole through the housing and the bearing sleeve to lock them together but still be easy to take apart if needed.



I also drilled a small oil-hole through the securing  screw which can be seen from the picture in the tailstock.



Then I made some different ends to fit, but the one I show here is the tip that I use to fit my small drillchuck etc.



This tip mimics the MJ-189/Unimat 3/4 spindle nose on one end and has the 12 mm dia end for the center in the other. Using this tip I can fit different tools from my MJ-189 machine range such as drill chuck ...



... or a small 55 mm diameter scroll chuck, ...



... or a 60 mm 4-jaw, ....



... or a face plate that can have anything fastened to it.



The other tips are:
  • A small male center allowing the turning tools to get very close to the end of the work.
  • A female center for supporting thin bars without havin to centerdrill the end.
  • A large diameter pipe center.
  • A larger diameter flat pushplate used for example for thread finishing using dies.

Well thatīs about it. Another useful addition to the C3 tool box, and also widening the use of the parts for the MJ-189 at the same time.

Thanks for watching  :thumbup:

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline krv3000

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #1 on: June 24, 2012, 10:45:42 AM »
hi a job well dun

Offline Stilldrillin

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #2 on: June 24, 2012, 11:46:38 AM »
Peter.
Very handy tooling. Very nicely made.  :thumbup:

Well done!   :clap: :clap:

Defor
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline andyf

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #3 on: June 24, 2012, 11:56:11 AM »
Nice stuff, Peter!

What do you anticipate using the free-to-rotate 4-jaw, drill chuck and faceplate for?

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline PeterE

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #4 on: June 24, 2012, 12:49:26 PM »
krv and Defor, thank you!

@andyf: The reason for making possible to use the chucks etc in the tail stock is to support oddly shaped stuff which may go out of balance. For instance the heavy end the wrong way so to say, and no chance of using a normal live center, or if you simply do not want to remove the thing from the chuck from start. Another example can be to support a long slender thing held in the drill chuck to lessen the risk of it bending away from the turning tool bit, a longish conical pointer where a travelling steady does not work.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline DaveH

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #5 on: June 28, 2012, 07:05:34 AM »
Peter,

That is a very handy piece of kit you've made - will come in very useful  :thumbup: :thumbup: :thumbup:
 :beer:
DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline PekkaNF

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #6 on: June 28, 2012, 07:29:29 AM »
Very nice work. Also enjoyed your reasoning and solutions.

Any change for additional photos on remaining interchangeable tips? I can vision them but everyone has some design ideas.

Pekka

Offline Fergus OMore

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #7 on: June 28, 2012, 10:35:18 AM »
As an owner of a MJ189, I also enjoyed your additions to your tooling.
Might I mention that a Reg Tingey also wrote up how to make up accessories in his Making the Most of the Unimat. This is now out of print but it is copied in the YahooGroups Unimat forum.
True most of it is dimensioned for the original SL but a downloaded copy can be most useful.

I bought my machine together with a host of accessories really for the time when I was somewhat older( I'm only 82) from an old chap  who went into residential care.

Cheers

Offline DaveH

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #8 on: June 28, 2012, 01:11:38 PM »
I bought my machine together with a host of accessories really for the time when I was somewhat older( I'm only 82)
Cheers

Hi Norman,
Good for you   :thumbup: :clap:
 :beer:
DaveH

(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline PeterE

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #9 on: June 29, 2012, 04:45:10 PM »
Thanks a lot everyone!

@Pekka: The other tips will be made according to or very nearly the early drawings below. I have not yet had time to make them, but they and the little wooden tray will be made during my upcoming vacation  :D

The tips.

Please note that the outer diameter of the shanks now are 12 mm diameter instead of 10. This as I found during work that 12 mm would be far better for the needle roller thrust bearing I had and still make the brass bearing steady enough. A suitable material for the tips or tip shanks would be 12 mm dia silver steel (drill rod) as it is precision ground from start and thus only need "end manufacturing" which simplifies a lot.

Tip no 2 now tapers from 6 to 10 mm diameter, but when it increase to 12 mm I will make the tip with a straight turned-down part at 6 mm diameter and let is taper quickly (30-ish degrees) to the 12. This will make a center small enough to allow tools closing up to a work piece end.

Also, as you have already seen, the chuck attachment is drilled out in the same manner as the Unimat tailstock.

The sketch for the wooden storage block layout will look something like the following.


I hope this may trigger a though or two.

@Fergus: I have been on the look-out for Rex Tingeys book but not yet found it. I have heard that it contains many useful small items for the Unimat/MJ-189, and probably also the SIEG C0 range machines. Must look through the Unimat forums files and see if I can get hold of a copy (tahnks for pointing that out :thumbup: ).

As said at the beginning, I made much the same set of tips from the Bob Loader book and they turned out as below.


BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline PeterE

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #10 on: July 01, 2012, 04:40:45 PM »
Thought I would just show the tips made so far.

1 - The Chuck mounting tip (better picture than the old one)


2 - An ordinary but smaller tip than my normal live center.


3 - The very small tip. I did not want to make it longer as it might become unstable.


4 - The small female or hollow center


5 - One of the push pads, this one is for a threading die handle (sorry for the blurryness didnīt notice until afterwards.)


6 - The large pipe center. My ordinary live center handles up to 25 mm dia and this one from 20 to just under 50 mm dia.


7 - The large hollow center for things up to about 40 mm dia.


These should handle most situations, but it is very easy to make new ones as required.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline Alan Haisley

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #11 on: July 18, 2012, 09:23:33 AM »
Very nice work. I'm curious about how well the brass bushing performs. While thinking about making a live center I keep thinking in terms of using roller bearings where you use plain brass. I'd like to hear some pro and con opinions about the two different designs.

Alan

Offline krv3000

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #12 on: July 18, 2012, 09:29:13 AM »
yep well dun good work and a good post

Rob.Wilson

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #13 on: July 18, 2012, 12:11:51 PM »
 :scratch:  how did i miss this thread  :palm:

Hi Peter , now thats a cracking set of centres you have made for the lathe , :clap: :clap: :clap: :clap: looks like you have covered all the bases  :dremel:


Rob

Offline PeterE

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #14 on: July 18, 2012, 03:49:39 PM »
Hi all and thank you for kind words!

Alan; the brass I used is a type of hard brass that suits very well for bearings. Together with a light oil film it works a treat. I did think of using needle roller bearings to begin with, but decided that it would be over-engineered so stayed with plain a bearing. This is a light duty center basically aimed to give support and some guidance for various odd setups, not aimed for "full force" work.

There is a bearing in the bottom of the thing, a needle roller thrust bearing to avoid rubbing or milling the bottom. I guess I sould have used either one larger or three smaller ball bearing balls as bottom bearing, but decided on the compact needle roller thrust version.

I have the smaller vesion made for my MJ-189 from the Bob Loader book drawings and those use a plain bearing in the form of the housing itself. No problem with that either. So my reasoning was that if the brass bearing variant turns out to be unsatisfactory it is easy to change to either roller bearings or a plain bearing of cast iron.

krv3000; thanks and good to hear you liked the post.

RobWilson; Thanks a lot! The made bits are my parts of basic kit leaving room for other more specific additions.

As a means for keeping the bits in order I also made a stand from a piece of old oak-topped flooring:

The tommy bar is for the chuck mount.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline John Stevenson

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #15 on: July 18, 2012, 03:54:22 PM »
:scratch:  how did i miss this thread  :palm:


Rob

Blinded by reflected light off CNC mill parts by any chance ?   :zap:

John S.
John Stevenson

Offline PekkaNF

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Re: Peter E - Light Duty Live Center w Changeable Tips
« Reply #16 on: July 21, 2012, 11:58:30 AM »
Great work and very good explanation Peter! Thank you very much.

Pekka