pressbrake1
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For tight fit I use an old reamer or gently blunt one .
Accuracy isn’t a given it take time and experience
Accuracy isn’t a given it take time and experience
- Thread starter Beanwood
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sako243
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As a picture paints 1000 words- this is what I am trying to replace. It has worked reasonably well in the form shown, but was only supposed to be a prototype- then I ended up using it several hundred times… I hadn’t hardened anything or polished it enough- but you get the gist.
The holes are each 4mm.
The holes are each 4mm.
This is my first foray into reamers - so don't have any old ones - so if I need one I have to buy it. I also bought 'cheap' as I don't know the right size (Accuracy and exerience!), and only need it for 8 (Well 16 or so if it works well) holes. Interesting idea on blunting one though - would I just treat it roughly, or with no oil ?
I hadn't realised, but the picture above probably shows the problem I'm trying to solve - some of the chads have elongated/stretched aluminium on one side. Those are where it's been torn away by the punch, rather than sheared - so leaving a ragged edge on the finished part.
If I get the hole and pin size match closer, I hope to eliminate/reduce that.
pressbrake1
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One thing is to grind relief on the punch so there’s more shear action . With sheet material up to about 4mm this really helps
Yes, I've wondered about that, but never worked out how that could be achieved. With a really small grindstone on a dremel or similar, whilst turning in the lathe?
Also wondered if a 5/32 reamer would be a better fit after all...
Would a bull nosed slot drill bit do it?
Brad93
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Punch grinder or a tool & cutter grinder
pressbrake1
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Just a half moon going through from one side to the other so it shears . A hollow in the centre gives a positive punch but it’s still punching in one go
Had an hour spare late yesterday...
Cut myself a little piece of steel, turned it down to the perfect dimensions on the lathe..
Mounted the rotary table on to the lathe, put the piece into a chuck onto a rotary table (easiest way to hold it).
Used my new 5/32" slot drill to drill 6 holes...
Took the piece out and tried a 4mm silver steel rod - which was EXTREMELY loose.
My first learning for the day
- my little mill which in the same realms of rigidity as a Bridgeport et al was made MANY times worse by having a rotary table, and a chuck thrown into the mix. I know it was wrong - but didn't realise how wrong it would be.
Next to lighten my mood, as I was surprised how loose it was I just thought to check the 4mm Silver Steel for size. Well. My second learning of the day - It seems that some suppliers may be selling 4mm, but actually supplying 5/32.
(As I have some of supposedly each, and they are identical - at about 3.95mm.
So, the 3.9mm dormer drilling slightly oversize (thanks to my drill runout probably) is ALMOST big enough for the hole without further work. I'm now left wondering about just hardening some silver steel and banging it through like a broach. Would that work?
I need a cup of tea.
Cut myself a little piece of steel, turned it down to the perfect dimensions on the lathe..
Mounted the rotary table on to the lathe, put the piece into a chuck onto a rotary table (easiest way to hold it).
Used my new 5/32" slot drill to drill 6 holes...
Took the piece out and tried a 4mm silver steel rod - which was EXTREMELY loose.
My first learning for the day
- my little mill which in the same realms of rigidity as a Bridgeport et al was made MANY times worse by having a rotary table, and a chuck thrown into the mix. I know it was wrong - but didn't realise how wrong it would be.Next to lighten my mood, as I was surprised how loose it was I just thought to check the 4mm Silver Steel for size. Well. My second learning of the day - It seems that some suppliers may be selling 4mm, but actually supplying 5/32.
(As I have some of supposedly each, and they are identical - at about 3.95mm.So, the 3.9mm dormer drilling slightly oversize (thanks to my drill runout probably) is ALMOST big enough for the hole without further work. I'm now left wondering about just hardening some silver steel and banging it through like a broach. Would that work?
I need a cup of tea.
