Expanding arbour

[Gerhard Olivier]

Could anybody explain how to make a 12mm diameter 20mm long expanding arbour that has to have a wider register to back material onto.  The other post somewhere made me think that this will make the tailstock die holder job easier but cant afford to buy the set from ARC at moment

Gerhard

[bogstandard]

Gerhard,

I hope this helps. Done in a bit of a rush, but should explain it OK

After you have turned down to right size, put part on and tweak screw to lock it on.


John

[Baldrocker]

John
Have you ever considered publishing a collection
of your crap o cad drawings, say 5000 of them?
Sure to be a hit in the m e fraternity plus an invaluable resource.
BR

[Gerhard Olivier]

Thanks Bogs -ideal and not to difficult to make

20mm EN1A MS
 



Tidy the back end




Cut down to 12.5mm drill and tap m8



add M8 bolt and skim to 12mm and the reduce and cut bolt to an angle



Leaving a 12mm expanding arbour.




Gerhard

[bogstandard]

But does it work Gerhard?


BR,

I find that run of the mill people understand a scrawled piccy much easier than a cad or works drawing.
This is how it is done on the shop floor when discussing how to get a job done.

The job is usually finished and all working before the engineer and draughtman have had time to draw it up.


John

[mklotz]

An even simpler bodge is to tap the arbor end with an NPT (National Pipe Tapered) thread and use a (commercially available) NPT pipe plug to effect the spreading action.  I've done several that way over the years and keep a collection of smaller pipe plugs on hand for that use.

If John does publish his C-o-Cs, I have the perfect title for the book - Pile of Crap.
(Just kidding, Bogs. It's not unusual for a C-o-C drawing to be the only design reference for many of my jigs and fixtures.)

[bogstandard]

Marv,

I was actually going to suggest a first cut tapered tap, and just by screwing a normal thread into it, it will expand enough, but I thought that was just too much of a bodge.


John

[mklotz]

Too much of a bodge for the likes of us, John?!  Surely you jest.  The concept begs definition.

I can tell from your no-nonsense, get-er-done approach in the workshop that you, deep in the dark of night, have bodged just as wildly as I.  We've just got the good sense to not advertise it.

[dsquire]

Too much of a bodge for the likes of us, John?!  Surely you jest.  The concept begs definition.

I can tell from your no-nonsense, get-er-done approach in the workshop that you, deep in the dark of night, have bodged just as wildly as I.  We've just got the good sense to not advertise it.

Until NOW! 

I just couldn't let that one pass. 

Cheers 


Don

[bogstandard]

There are times for, and times not, and to err is only human.

As long as it can't be detected, then it is perfectly acceptable. The only exception is when someone's life depends on it, then definitely not.


John

[Davo J]

Talking about bodgey and when someone's life depends on it,
My son in-law told me a story of when his father and grandfather made an elevator lift for the grandmother as she could not walk down all the stairs. Well the lug they welded on top was bodgey welded (they had no trade and little experience in welding). It broke and she dropped on the first lift and spent several months in hospital with broken legs.
Dave

[Gerhard Olivier]

But does it work Gerhard?


John

Not sure if you mean COC or the arbour but the answer is yes to both.  My mind understands COC better than any other explanation.

Used the arbour to cut 6 die holder tonight and they gripped well enough to reduce the body from 41 mm to 26mm in no time at all best of all is I could cut from one end and then turn piece around and finish the cut with no visible and feelable joint ( just to test consentricness)

Thanks again.

Gerhard

[bogstandard]

I was just asking to see if your arbor worked.

Glad it does.

John

[ieezitin]

Nicely done Geroli.   

Just a reference to Bodging, I love to cut corners, just ask my wife she will tell you that for nothing. But in the shop when I cut corners and it back fires I feel like I should face punch myself.
But old father time is wise and now I get less facial swelling. Another plus is your product comes out refined and shows quality.