Lathes & M/C tools

[2mm Dabbler]

Looking at the jig axles James is using, and the short length required to be turned to 1mm I don't believe distortion would be a problem assuming minimum overhang from the chuck or collet.

 

 

Whilst I've mentioned four jaw chucks and 'dialing in', though not DTI's specifically, I'm not sure James has either or experience in their use. I believe he's not possessed the U3 for long.

[AndyID]

Probably me just being thick but I still do not understand what Down-Under is trying to achieve.

 

Rather than modifying some existing part (which is always a bit tricky) it might be simpler to make an entirely new part and one good way to ensure that everything is beautifully concentric is to turn it between centers, but without knowing the dimensions and material of the finished part that might be a load of baloney 😀

[polybear]

56 minutes ago, AndyID said:

Probably me just being thick but I still do not understand what Down-Under is trying to achieve.

 

Rather than modifying some existing part (which is always a bit tricky) it might be simpler to make an entirely new part and one good way to ensure that everything is beautifully concentric is to turn it between centers, but without knowing the dimensions and material of the finished part that might be a load of baloney 😀

 

I'm not familiar with the Avonside jig (I have a Hobby Holidays jig) but my guess is that D.U. wants a set of "axles" for bearing sizes other than 1/8th, or more likely for the coupling rods.  Hobby holidays sell such axles for their own jig with either 1mm or 1.5mm spigots, depending on what crank pins the user prefers. 

[Enterprisingwestern]

As I don't possess a lathe, to do jobs such as this I use rod and tube of an appropriate diameter, would that not work in this instance?

 

Mike.

[2mm Dabbler]

4 minutes ago, Enterprisingwestern said:

As I don't possess a lathe, to do jobs such as this I use rod and tube of an appropriate diameter, would that not work in this instance?

 

Mike.

The photograph I've included above shows, apart from the reduced end, a collar and a threaded portion. Fabricating as you suggest is certainly feasible if the appropriate size material is available, you'd need to ensure the thread is 'square' for accurate use. 

 

Definitely worth considering as an alternative.

 

Michael

[Down_Under]

On 06/07/2022 at 00:41, AndyID said:

 

Can you post a dimensioned sketch of what the finished part should be?

Hi AndyID,

This is what I am trying to achieve:

 

The short pin - modify a 3mm short pin by removing the red area. This seems to be the easiest option, since there is little defection to begin with.

 

 

 

The longer pin - option #1 - modify long 3mm pin and machine off the red area.  However, issues with deflection when the tool is introduced.  The jig axles are steel and quite hard (i've reduced RPM and slow feed rate) to ensure good "chipping". seem to have helped - along with a sharp tool. 

 

 

 

13 hours ago, polybear said:

An alternative may be to centre-drill the end of some 1/8th or 2mm rod (using a very small size 0 centre drill) and then drill 1mm & insert a piece of 1mm silver steel (or maybe the shank of a 1mm drill bit).

 

You mean like this? 

 

Long pin Option #2 - start with 2mm pin and centre drill end to take 1mm pin. Pros - can hold the pin closer to the chuck / collet reducing deflection

 

 

11 hours ago, polybear said:

 

Yes, but likely no worse (and possibly a lot better) than trying to turn a 1mm spigot without distortion; a steel 1mm spigot would be a lot stronger too.  The other option (if James has one) would be to hold the stock in a 4-jaw chuck and centre it using a DTI.

 

I have a 4 jaw (just need to find the chuck) - and a set of collets on order (waiting for delivery from UK) so can use either or these. Also have a dial gauge to ensure running true in the 4 jaw. Which is the perference for ensuring centricity ? 

 

Thanks for all the advise - the first time lathing since I was 15 (20 on years ago), so apologies for any miss use of terminology. 

 

 

 

 

Edited July 7, 2022 by Down_Under

[Down_Under]

4 hours ago, AndyID said:

Probably me just being thick but I still do not understand what Down-Under is trying to achieve.

 

Rather than modifying some existing part (which is always a bit tricky) it might be simpler to make an entirely new part and one good way to ensure that everything is beautifully concentric is to turn it between centers, but without knowing the dimensions and material of the finished part that might be a load of baloney 😀

 

Yes, that would be the most logical I think - I just lack the skills, or the tools (eitehr thread cutting attachment, cutting tool or die (?))  at this moment in time to turn up the thread - something to learn for sure. 

[richbrummitt]

I’ve found some quick change tool posts for watchmakers type lathes. The one linked below comes with a ‘device’ that looks like it has a bearing each side of the holder. What I don’t understand is what is it for? 
 

https://www.ebay.co.uk/itm/364471781304 

 

If I don’t need it I could get one of their cheaper sets without this part. 

[froobyone]

9 minutes ago, richbrummitt said:

I’ve found some quick change tool posts for watchmakers type lathes. The one linked below comes with a ‘device’ that looks like it has a bearing each side of the holder. What I don’t understand is what is it for? 
 

https://www.ebay.co.uk/itm/364471781304 

 

If I don’t need it I could get one of their cheaper sets without this part. 

From what I understand it's for squaring a workpiece in the chuck. You place the bearing facing the work and spin the chuck. Then you advance the bearing against it. 

Dan

Edited December 12, 2023 by froobyone

[smokebox]

Used to ensure parts are running true in the chuck.  With the part held not too tightly in the chuck, advance the tool against the part.  When running true tighten the chuck completely.  

[Vecchio]

Would do that rather with a dial gauge...