Rivermetal
Member
For the guys who have homemade air planishing hammers and have experienced a failure of the top die like this...
https://flic.kr/p/211MFP9
https://www.flickr.com/photos/154875609@N02/shares/jD645S
It happens because the air chisel hole side hits on the radius of the die making a groove which turns into a crack, breaking off the post. Make sure the barrel of the air chisel has sufficient clearance on the radius. The die should only hit on the flat under side of the die, 90 deg to the post.
https://flic.kr/p/211MCxE
To check this magic marker the barrel and the die radius area, place it in the bore and twist it , if you get a mark on the die it will break
https://flic.kr/p/HazayF
https://flic.kr/p/ZKNFH6
https://flic.kr/p/2274W3r
This pic indicates contact on die radius so bore of air chisel must be opened up. I do this by first placing a piece of rag down the bore to prevent filings from entering, you can remove it with a pick later. Using a die grinder removing a little material at time, apply magic marker again and recheck, it may take 2 or 3 trys
https://flic.kr/p/224puP9
I used this deburing tool as the final step to clean up the radius... there great for putting the final cutting edge on you lawn mower blades too!!!!
When your done you should not be able to see ant daylight between the barrel of the air chisel & the die.
it dosent hurt to check your lower anvil too
https://flic.kr/p/ZKNBAi
https://flic.kr/p/211MFP9
https://www.flickr.com/photos/154875609@N02/shares/jD645S
It happens because the air chisel hole side hits on the radius of the die making a groove which turns into a crack, breaking off the post. Make sure the barrel of the air chisel has sufficient clearance on the radius. The die should only hit on the flat under side of the die, 90 deg to the post.
https://flic.kr/p/211MCxE
To check this magic marker the barrel and the die radius area, place it in the bore and twist it , if you get a mark on the die it will break
https://flic.kr/p/HazayF
https://flic.kr/p/ZKNFH6
https://flic.kr/p/2274W3r
This pic indicates contact on die radius so bore of air chisel must be opened up. I do this by first placing a piece of rag down the bore to prevent filings from entering, you can remove it with a pick later. Using a die grinder removing a little material at time, apply magic marker again and recheck, it may take 2 or 3 trys
https://flic.kr/p/224puP9
I used this deburing tool as the final step to clean up the radius... there great for putting the final cutting edge on you lawn mower blades too!!!!
When your done you should not be able to see ant daylight between the barrel of the air chisel & the die.
it dosent hurt to check your lower anvil too
https://flic.kr/p/ZKNBAi
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