Talk to me about soft jaws...

[Hood]

A couple of pics using the home made setting ring.


Set into soft jaws ready for boring a 3mm step.

Step bored.

And the workpiece in the bored out step.

For this job I could have clamped a short piece of round bar at an appropriate diameter as I didn't need a through hole but the setting ring is easier than raking about for a suitable piece of round bar.

 

[Martin Hocking]

Not really an up to calibre comment compared to the info in this thread already but…

I have a recollection of seeing a tip published in MEW magazine about using some large nuts (*ahem*) slipped over regular jaws as a way of making temporary soft jaws which seemed like a very handy idea, well to a cretin like me at least anyway…

 

[Hood]

Not really sure how that would work as how would you hold them onto the jaws? Only way I can see is you fully close the jaws to clamp the nuts then bore them out undersize , if you bored them out to size you would have no means of tightening any further to clamp the stock.

 

[Seadog]

Large nuts that fit over the jaws. Clamped tight then bored?

 

[Hood]

Large nuts that fit over the jaws. Clamped tight then bored?

Yes but then you need to bore undersize as if you bore to size, which is the ideal, then you would not be able to tighten further to grip the stock.

 

[Seadog]

Well bore them slightly under size, or fit some shims before boring.

 

[pressbrake1]

I’ve done some terrible lash ups with soft jaws , so dreadful I’ll never tell

 

[Agroshield]

I have a recollection of seeing a tip published in MEW magazine...

It may be something related to that shown here:

What are these chuck jaws?

I have a 3 jaw with a gew sets of jaws, but I don't know what this set are for. The hex sections are held onto the jaw with a central hex bolt. The underneath of the large hex pieces are castellated like a bit so they can be rotated. It's like they are designed to be machined to accept a...

www.mig-welding.co.uk

 

[Martin Hocking]

Not really sure how that would work as how would you hold them onto the jaws? Only way I can see is you fully close the jaws to clamp the nuts then bore them out undersize , if you bored them out to size you would have no means of tightening any further to clamp the stock.

To be honest I’m not sure I do either, I’d have to dig out the issue which could take years! Please hold your call is important to us…

I reckon a bit of shim stock between nuts might do it but I’d probably just go a smidge undersize to keep my slapdash reputation!

 

[Martin Hocking]

I’ve done some terrible lash ups with soft jaws , so dreadful I’ll never tell

There’s hope for all of us then!

 

[Martin Hocking]

It may be something related to that shown here:

What are these chuck jaws?

I have a 3 jaw with a gew sets of jaws, but I don't know what this set are for. The hex sections are held onto the jaw with a central hex bolt. The underneath of the large hex pieces are castellated like a bit so they can be rotated. It's like they are designed to be machined to accept a...

www.mig-welding.co.uk

They could well have been the inspiration.
I’ve not seen those before thanks agro.

 

[Agroshield]

Please hold your call is important to us…

There is a spreadsheet index to the magazine, updated monthly, here:

The Latest INDEX to Model Engineers' Workshop | Model Engineer & Model Engineers Workshop

The MEW index to issues #1 - #333 is out MEW Index Folder link: https://drive.google.com/drive/folders/16Bbid9m5Sh-7qpQEaO69Tn-z-kDElVOi?usp=sharing The pdf ...

www.model-engineer.co.uk

Another index to ME, MEW, EIM here:

Model Engineers Workshop

 

[Brad93]

Bored the soft jaws today, had issues with chatter but got a half decent finish in the end.

I don't think it helped i was using a piece of 6" thin wall pipe

 

[Hood]

6" wall pipe?

 

[Brad93]

6" wall pipe?

thin wall i meant sorry

 

[Brad93]

Anyway on a 60mm shaft before boring (I would say the jaws were meant for 55-60mm shafts from the last guy machining them)
i had 0.0015" runout, which i unacceptable for what i was attempting to do.

This was also throwing out my tailstock end quite a bit despite a decent centre in the end of the shaft.

After boring, shaft chucked up and tighten from only one of the pinions, less than 0.0005" TIR, that was the most precise indicator i had with me.

 

[Brad93]

New problem today is i'm now certain the front v way of the carriage is getting no oil when pumped.
Applying it manually by oil can does little because the rubber wipers just push it off.

 

[Agroshield]

New problem today is i'm now certain the front v way of the carriage is getting no oil when pumped.

How does the oil distribution system work? It might be possible to block off the other exits from the pump so that only that one is connected and pump through the blockage. The oil will take the path of least resistance and if you force it to go that way, it has to go that way. Maybe a quick blast with an airline would provide more velocity than the pump and shock the oil line into working. Could you rig it up with diesel in it and leave it under slight pressure overnight? Can you poke the line with some thin wire?

What other reasonable options are there before being forced to remove the saddle?

 

[Brad93]

How does the oil distribution system work? It might be possible to block off the other exits from the pump so that only that one is connected and pump through the blockage. The oil will take the path of least resistance and if you force it to go that way, it has to go that way. Maybe a quick blast with an airline would provide more velocity than the pump and shock the oil line into working. Could you rig it up with diesel in it and leave it under slight pressure overnight? Can you poke the line with some thin wire?

What other reasonable options are there before being forced to remove the saddle?

None of those are possible, the oil on a colchester also lubricates the carriage gears

 

[Martin Hocking]

Take off the rubber wipers and squidge some oil in there in the mean time?