machining conn./coupling rod ends.

[andy smith 7Participant @andysmith7]

[andy smith 7Participant @andysmith7]

Hello Gents,

First post for me, complete newbie to model engineering so please accept my apology if this question has been done to death!.

How are the round big / little ends of a coupling rod machined? I have a small lathe( 3 1/2 inch centre height) a vertical slide,so can do a little milling, but for the life of me I can,t picture how to go about this machining.

Needless to say for someone who served his time at Leyland Motors in 1980-84,

I am a little embarrassed My God was it really thirty years ago.

By the way, the loco is the Achilles 0-6-0. Any help / pointers would would be greatly appreciated. Thanks Andy.

[Jim GuthrieParticipant @jimguthrie82658]

Andy,

 

A method I have used some years ago on the coupling rods for a Gauge 1 loco was to mount a spigot on the vertical slide which fitted the bearing hole on the coupling rod. With the milling cutter in the chuck, mount the coupling rod on the spigot and feed the coupling rod down onto the milling cutter using the other end of the coupling rod as a lever to rotate the rod on the spigot to form the circular end.

 

I think I got the idea from the Model Engineer many years ago. It does look to be a bit dodgy but it does work – you just have to be very careful. You need a lock nut and washer on the spigot to hold the coupling rod firmly and you have to apply very light feeds. You would normally have to position the spigot above the milling cutter to give you sufficient angular movement to do an end in one setup. If you feel the coupling rod is not long enough to give sufficient control, you can clamp another length of metal to it to give additional leverage.

 

Nowadays I have a milling machine and a rotary table and I would use them in preference for the same job.

 

Jim.

[AndyPParticipant @andyp13730]

Andy,

 

I like filing buttons for that sort of job, as described in hint no7 here

 

Our club loco is an Achilles – absolute cracker!

 

Andy

[Terry LaneParticipant @terrylane]

Filing buttons will do the job, but this is a gizmo I made for use in the mill, you may be able to adapt it for lathe/vertical slide use.

[SpringbokParticipant @springbok]

Firstly Welcome

 

I use a rotary table on the mill, have used a bit of a stub arbour tapped .25 could be almost any dia depends on your kit, this goes into centre of table and I make up stubs to suit the job which screw into the arbour, or you can do what tel has done will post a pic to explain better.

 

Good luck

 

Bob.

 

 

[Clive HartlandParticipant @clivehartland94829]

Remember to use the ‘Up cut’ method if you do it in a lathe with a stub, it will grab otherwise and destroy the job and a bit of you as well.

As stated , a fine feed and with great care!

 

Clive

[andy smith 7Participant @andysmith7]

Hello Gents.

Thank you for the welcome and the superb ( and very quick) replies. Considering it was my first post I am quite humbled by the response. What a great forum.

Going to do some practice pieces and see which method I,m best at

Great to hear your Achilles is a good un” AndyP, Thoroughly enjoying myself with this project ( quite addictive is,nt it )

 

All is well with the world now ( until the next question)

Many Thanks again Gents.

 

Andy.

[SpringbokParticipant @springbok]

–

Edited By Springbok on 13/10/2011 17:12:09

[Gray62Participant @gray62]

Clive, can you clarify what you mean by ‘Up Cut’ I never use my lathe for milling parts so my understanding of milling cutting is either that of climb milling or conventional milling, how do these techniques relate to ‘up cutting’ on a lathe ?

[SpringbokParticipant @springbok]

 

Edited By Springbok on 14/10/2011 01:19:37

[SpringbokParticipant @springbok]

Hi hope this comes out, pic of rotary table

Bob

Edited By Springbok on 14/10/2011 01:32:07

[Clive HartlandParticipant @clivehartland94829]

The reference to ‘Up cutting’ means that as the lathe and the end mill in the collet turn anti clockwise then a job like the post asks about is put against the end mill and rotated anti clockwise when you look at it end on.

Try it the other way and it will grab the job and bingo you have no job and maybe sore fingers.

The force of cutting is quite considerable!

This method is quite dangereous and great care should be taken, if you have a rotary table use it!

‘Up cutting’ term is the same as conventional milling, ‘Down cutting’ is not normally used on a mill that  has no backlash compensation and  the tool climbs on the job. If its a small diameter cutter it will snap.

 

 

Clive

Edited By Clive Hartland on 14/10/2011 09:08:02

[andy smith 7Participant @andysmith7]

Hello Gents,

 

Thanks Clive for the extra advice, if I understand you correctly , if the mill were to grab using the upcut method it would pull the job out of my hand and away from me. Rather than pushing my hands down towards the bed / apron or whatever is in the way.

Quite like the idea of filing buttons But like the idea of a rotary table even more

Looks like you are having some problems posting the photo Springbok.

 

Andy.

[Clive HartlandParticipant @clivehartland94829]

No Andy, I will have to correct that for you.

If you offer the coupling rod end which you have held in a pivot secured in the tool post with the end mill rotating towards you then start the rotation of the rod end towards you.

This in effect is ‘Upcut milling’.

If you were to offer the rod end by rotating it towards the end mill then it will be ‘Downcut milling’, this is the dangereous way.

Stick to hardened filing buttons as it will be a lesson making them both in turning and in hardening.

With a file you can stop anytime but using a cutter in the collet in the lathe you have to be sure that all will be safe and sure. Again consider the rotary table as you have many crank ends to turn.

They will last a long time and can be used again and again.

I have completed all the motion links and cranks for my Evening Star ( see pic. in my photos) It all rotates without binding.

 

Clive

[andy smith 7Participant @andysmith7]

Hi Clive,

Thanks for the clarification, feel a bit of a numpty really . But in my defence it is a long time ago since I did this sort of stuff.

Have to agree that filing buttons will be a great excercise and very practical at the present time. I most certainly will be investing in a rotary table at some point.

Your 9F is a credit to you, absolutely stunning.

 

Andy.

[DurhambuilderParticipant @durhambuilder]

I’ve just finished the 040 version AJAX as a first loco, it’s fantastic on the club track so you’ve chosen a good ‘un. I have a set of 10mm thick steel boiler formers if you want to borrow them.

[andy smith 7Participant @andysmith7]

Hello Durhambuilder,

Good to hear about your clubs AJAX . Thank you for the offer of the boiler formers, but I am quietly confident that I have not got the skill to make a boiler.

When the time comes it looks like I,m going to have to buy one ( ouch.)

 

Andy

[SpringbokParticipant @springbok]

Hi Andy

I do seem able to get pics onto the posting so if you give me your email address ( your profile does not show it) I will send you some including details.

Will also send you details of a superb boiler maker if you are interested though be warned they are not cheap but as they say….

 

Bob

[andy smith 7Participant @andysmith7]

Hi Bob

Message sent. Andy

[SpringbokParticipant @springbok]

Edited By Springbok on 16/10/2011 04:59:56

[SpringbokParticipant @springbok]

Hi Andy will send more detailed pics as promised worked out how to post pic’s on this site very convoluted to say the least

 

speak to you soon

 

Bob

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