Author Topic: Peening tips?  (Read 753 times)

Offline Mike K

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Peening tips?
« on: October 27, 2021, 05:20:45 PM »
I'm making a pair of Kant Twist clamps.  I'm not using threaded fasteners to hold the plates together; according to the plans I have, I've made pins and am peening the ends.  The trouble is that the slop that I thought would go away hasn't.  My pin shoulders wound up about 2-3 thou smaller than the holes, and they're about 102 thou long going into 16 gauge (62 thou) thick arm plates.  After a few minutes of peening with a small ball pein hammer I have the pin staying in and not falling out, but the 2-3 thou slop is still there and the extra 40 thou that I thought was needed for peening hasn't reduced that much.  So, there's slop in both directions.

I'm wondering if: 1) My hammer is too big?...it's 8 oz and on the scale of the 3/16" pins maybe the end is too flat?  B) The extra 40 thou beyond the plate thickness is too much?  The plans were calling for 60 thou, though.  And iii) I just need to spend much more time hammering?

Any tips for peeing would be appreciated.

Offline awemawson

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Re: Peening tips?
« Reply #1 on: October 28, 2021, 02:46:01 AM »
You are peening round the edge of the pin not just hitting it square on arenít you?
Andrew Mawson
East Sussex

Offline Mike K

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Re: Peening tips?
« Reply #2 on: October 28, 2021, 09:05:33 AM »
Well, no...I was hitting it square, but with the round nose end of the hammer.  I guess this is an obvious mistake.

Offline Mike K

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Re: Peening tips?
« Reply #3 on: October 28, 2021, 09:45:38 AM »
Actually, I was hitting every spot on the face, square on as well as the edge.  I think I need a smaller nosed tool, like maybe a small drift with the nose rounded?  The pin face is only 3/16".

Offline chipenter

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Re: Peening tips?
« Reply #4 on: October 28, 2021, 10:16:00 AM »
Rivet snaps are the tool to use , you can make them with a ball nosed end mill or buy them ready made . 
Jeff

Offline philf

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Re: Peening tips?
« Reply #5 on: October 28, 2021, 10:54:40 AM »
Mike

Far from your hammer being too big I'say that 8oz is much to small. Try a 2lb hammer.

Phil.
Phil Fern
Location: Marple, Cheshire

Offline Mike K

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Re: Peening tips?
« Reply #6 on: October 28, 2021, 11:25:24 AM »
My thinking for needing a smaller hammer is that the peen end will have a smaller radius.  The peen of a larger hammer has a face that's nearly flat compared to what I'm peening.  That would be like hitting it with a flat faced hammer, no?

Offline WeldingRod

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Re: Peening tips?
« Reply #7 on: October 28, 2021, 11:26:35 AM »
Maybe a beefy center punch?

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Offline Mike K

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Re: Peening tips?
« Reply #8 on: October 28, 2021, 12:32:48 PM »
Okay, I finished up one side of the pin and did another pin very quickly.  First pin literally took about ten minutes.  Second pin under a minute.  Both pins are nice and tight.  I changed up a few things.  I was using the "drill block" directly on the vinyl floor (concrete slab underneath).  I moved that onto a wood block that I use as a car jack stand.  I also took bigger swings, I think.  And I was angrier this time. :)

Thanks, guys.  I've literally never done peening before.  I think I should still get an anvil for future use.

 

 


Offline awemawson

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Re: Peening tips?
« Reply #9 on: October 28, 2021, 12:46:41 PM »
 :mmr:
Andrew Mawson
East Sussex

Offline Mike K

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Re: Peening tips?
« Reply #10 on: October 28, 2021, 07:36:17 PM »
Another question...

The elbow hole of that harm holds a pivot piece that the leadscrew fastens to...It'll turn as the clamp opens and closes.  I have a rod of bearing bronze that I was thinking of using for it.  Will that peen well?  Or will it distort too much and leave me with a bad pivot?  It's part #7 in the diagram.

 

Offline chipenter

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Re: Peening tips?
« Reply #11 on: October 29, 2021, 03:28:47 AM »
I made my pivot pins longer and when peening kept turning the pivot until it felt right .
Jeff

Offline efrench

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Re: Peening tips?
« Reply #12 on: October 29, 2021, 05:31:41 PM »
#7 and #4 are not peened on the real thing. 

p.s. One of the #3's is not peened.

Offline Mike K

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Re: Peening tips?
« Reply #13 on: October 29, 2021, 06:14:11 PM »
#7 and #4 are not peened on the real thing. 

p.s. One of the #3's is not peened.

Now that I think about it, it makes sense...the pivots don't need to be peened as the plates are already bound by the other pins that *are* peened.  And that explains why there is a #3 so close to that pivot.  Thanks.
« Last Edit: October 29, 2021, 07:40:09 PM by Mike K »

Offline Mike K

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Re: Peening tips?
« Reply #14 on: October 29, 2021, 07:39:13 PM »
I made my pivot pins longer and when peening kept turning the pivot until it felt right .

I may do this if the 16 gauge plate winds up being too flexible.  Thanks.