I have started fabricating my hammond 12x8x2 chassis for my EL84 PP amp and happened upon a NIB 4pc set of the Greenlee conduit punches model 7235BB with 0.89", 1.12", 1.36", and 1.70" actual hole sizes for $55 and free shipping.
I previously used a drill and step bit which worked OK but these punches were much easier and didnt warp the top plate at all - very clean cuts.
The 0.89" hole worked perfectly for the 9 pin chassis mount sockets and the 1.36" one worked great for my PCB mounted octal rectifier socket that needed full clearance.
Harbor freight has a similar one for $25 I think but not a convenient location so I figured after shipping and tax I would spring for the greenlee ones.
I cant wait - my Edcor iron arrives today!!! Might be up and running this weekend...
I previously used a drill and step bit which worked OK but these punches were much easier and didnt warp the top plate at all - very clean cuts.
The 0.89" hole worked perfectly for the 9 pin chassis mount sockets and the 1.36" one worked great for my PCB mounted octal rectifier socket that needed full clearance.
Harbor freight has a similar one for $25 I think but not a convenient location so I figured after shipping and tax I would spring for the greenlee ones.
I cant wait - my Edcor iron arrives today!!! Might be up and running this weekend...
The HF ones are not as hard nor are they machined as tightly (which makes them pinch instead of cut). They are fine for aluminum as long as you get a reasonably tight one (tolerance is all over the place). Cut steel a couple of times and they are trashed. The Greenlee ones are pricy but they work great. Haven't worn mine out yet either and I have used them for other things besides tube amps, including (*shudder*) conduit!
Yup, Greenlee punches rawk! I've got dozens that I acquired over the years up to 3½ inches. But since I only use NOS American parts, couduit punches are impractical for me. They're meant for EMT connectors which are oddball sizes. But if one uses Chicom sockets that are metric (oddball) sizes themselves, I suppose they'd be good to have. Find them on eBay or imports at Harbor Freight.
Knockout Punch Kit
Knockout Punch Kit
Hello ,
Greenlee tools are worth the price. For grins I tried HF punches they are junk! For the holes that I do not yet have a real punch I chuck up a hole saw in the drill press. I drill with a piece of plywood for backup. With the work piece backed up with solid wood the holes cut very clean. There is just a little ridge that needs to be removed. Another trick that works to slightly increase the size of the hole is this. Use a piece of hardwood dowel that just fits into the hole. Wrap the dowel with sand cloth and work the sand cloth around enlarging the hole as needed. This works out very neat clean and round. Custom size too.
DT
All just for just for fun!
Greenlee tools are worth the price. For grins I tried HF punches they are junk! For the holes that I do not yet have a real punch I chuck up a hole saw in the drill press. I drill with a piece of plywood for backup. With the work piece backed up with solid wood the holes cut very clean. There is just a little ridge that needs to be removed. Another trick that works to slightly increase the size of the hole is this. Use a piece of hardwood dowel that just fits into the hole. Wrap the dowel with sand cloth and work the sand cloth around enlarging the hole as needed. This works out very neat clean and round. Custom size too.
DT
All just for just for fun!
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Yes, they are normally coated in a sort of wax to prevent corrosion. It can be removed with most solvents, even WD40.
Indeed. I only have 3 Greenlee punches (all conduit sizes) but I have lots of hole saws. On aluminum, even a cheap set of wood hole saws work well in a drill press as long as you take your time and use lubrication to keep the temps down. I've done dozens of holes this way and haven't worn out a saw yet. They'll stay sharp as long as you don't let them get too hot. If you are dealing with steel, the same technique works with the more expensive hole saws meant for steel. I have a couple of these that I used to use to cut fan holes in computer cases. They have seen a lot of abuse but are also still sharp.
They were used. And stored. So had some dried lubricant mixed with dust on them.
They cut like butter
Hmm... a well-contorted analogy. Nice.
Seriously though, which size Greenlee punches (or which kit) is best to buy for most chassis mount octal and noval sockets?
..Todd
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