Terry,

I'm sure you know this, but: The amount of material used is largely irrelevant …

The important things are 'what material it is' and 'what the maker does with it'.

The common operating principle for these punches is clearly shown in Laurence Sweet's patent: **LINK**

https://patents.google.com/patent/US2384707

Build that properly, from good materials, and it will work, and will last

Build a rough approximation, from poor materials, and it will serve as a plumb-bob.

MichaelG.

Hi Terry

I have. Wish I had seen Michael G's info. Went all round the houses trying to get it to work.

To me shaft 17 canted over is the key. I put a ball bearing on the left hand side, the right hand side wants to be flat and so does 23.

As the spring is compressed the 2 cones come together and make shaft 17 drop down the hole, this is the hammer action.

On my punches the wear made it drop down the hole to soon.

HTH

Cheers Michael.

I've got an unbranded one with a knurled brass body that I bought from I don't know where, I don't know how long ago.

I do remember it was cheap – I think £2.99.

The punch point was too soft, so I made a new one from silver steel.

I use it regularly and it's worked fine ever since, with an occasional touch of the bench grinder to the point.

I'd assumed they were all like that – guess I'd better be careful if and when I come to replace it.

Thanks for the patent link Michael.

I have a couple of Eclipse ones that occasionally go into a permanent mis-fire mode. Usually corrected by winding the force spring tension right down and bringing back to the normal operation point. Sometimes needs tow or three goes tho'. Clearly the part that should tilt over to allow the force to build up when the end is pushed sometimes sticks in the straight up position so the force spring never gets pushed.

Are there any traps for the unwary when dismantling? I assume its wise to follow my usual precaution when dealing with things known to have springs of working inside a transparent container .

The external spring devices are interesting but needing both hands to operate and having to hold the business end in place whilst pulling the other end to stretch the spring looks little inconvenient. I'd have thought there was considerable risk of lifting the push point away from its proper position when pulling he spring out. Nice thing about the common push type is that the point is naturally seated in the right place as you operate it. I'm sure it doesn't happen but one has visions of the external spring flapping around when relased with considerable pinch potential.

Clive.

They're not brilliant and really they are only meant to make a shallow witness mark.

Edited By Michael-w on 23/09/2018 21:04:34

The automatic centre punch is I think intended for dot punching for split the dots marking out and machining, a rather heavier punch is required for drilling. Eclipse make two sizes of punch and if the dot punch is wound up to provide a full centre punch mark for drilling it is going wear quickly. The larger edition will make a centre punch mark but will be a bit clumsy for dotting duties. As usual it is use the right tool for the job. Maybe we are moving away from precision marking out as the availability of DRO for the home workshop relieves us of this old skill.

Mike

I inherited an Eclipse from my father, (MANY years ago, so it it has to be about 70 years old). It functions well, which is more that can be said of an unbranded cheaper version.. The latter does not function as well, or reliably.

As has been said many times, you get what you pay for.

Howard