Re-installing Hern Treadle NS 8x12 C&P

Yes, definitely remove any roughness from the inside of the hook casting. A Dremel tool with a grindstone should get you where you need to be, or a grindstone that would be chucked in a drill would work as well.

Definitely also lubricate the hook and shaft with a grease, anything you have will be OK. Just remember that every time two pieces of metal meet and move against each other they need some sort of lubrication,and that lubrication must be repeated on a regular basis corresponding to the use of the press.

I think some of the previous posts have also mentioned that the hook might need to be filed down so it doesn’t hit something or other, so check that as well to be certain extra pressure is not coming to bear on the hook, increasing the potential for wear.

I would say this is why a wrought iron hook, which I believe is what was furnished with the press by the manufacturer, is better — the surface inside the hook should not only be smooth but it should be very close to the same radius of curvature as the crank journal on the shaft so there is maximum surface contact to spread the pressure. The wear on your old hook indicates that the hook was significantly larger in diameter inside than the journal. In addition, cast iron is brittle and there can be a lot of stress on this part if you put a lot of pressure on the treadle — 150 lbs (average person’s weight) equates to about 300lbs on the hook.

Sadly, there isn’t much you can do now about the groove except to try to ensure that the hook rides on a different part of the crank journal.

Bob

This is interesting. From the indication of the wear points on the hook, either the hook was much larger then the diameter of the shaft or as the shaft wore down, the area of wear on the hook got smaller. This amount of wear seems excessive compared to presses I have seen with original hooks. As if it was never oiled. If your shaft is that much smaller than the curve diameter of the inside of the hook, you will get the same results. If you oil it, it may slow the wear but make sure the inside of the hook is very smooth and as close to the diameter of the shaft as possible.

The wear on the shaft is what I find the most distressing. You are going to need to solve this or you risk destroying the structural integrity of the main shaft of your press.

Dan

Well, a new hook filed smooth on the inside and regular lubrication EACH time you use the press may get you by for your lifetime of printing. It does not address the issue of wear and loss of metal on the crank journal. The journal and the new hook are of different diameters.
It is difficult to add metal to the journal and machine it down to the correct diameter. Sometimes when you don’t have the money or the correct machine shop to make the machine like new, you do a farm fix. Those old farmers were pretty ingenious and kept the equipment working.
You can build up the journal diameter with an epoxy material that is used for auto body repair. Red Hand and J-Weld are two names. The material is applied and when thoroughly dry, it is filed to as near round as you can make it. Slightly under the diameter of the hook. Get a piece of sheet copper, or possibly a piece of thin wall copper pipe. If pipe, split it and place over the journal. Grease the journal before placing the copper. Close it as best possible and you have a copper bushing. Apply more lubricant to the outside and attach the hook. Now the wear will come on the copper. Don’t forget to lubricate each time you use the press.
Get some ink on your shirt.

Plan B 1/2
Perhaps a bit easier than my first farm fix suggestion.
Get either some iron or copper wire. Copper easier to find. Wind the wire on the worn crank journal to the diameter of the inside of the hook. Apply grease and apply hook. Inspect regularly for wear.
You might wish to incorporate the copper bushing described in the first fix. That way the wear would be on the bushing rather than on the wire.
Regular lubrication.
Get some ink on your shirt.

Thanks everyone—this is so helpful! I’m kind of surprised that this hasn’t happened to anyone else (or else they haven’t checked the crank) and I was rather shocked to see it like that.

@Dan and @Bob, yes I was very concerned about installing the new hook for that reason, so I will follow inky’s suggestions. I do have a variable motor for the press, but I like to use the treadle more often than not.

@inky even though I come from a long line of farmers, I like your Plan B better.

Frankly I don’t think Inky’s suggestions will work very long — the wire won’t stay in place unless you weld it there, and building up the shaft with epoxy can be done but getting it smooth and exactly concentric will be challenging. Perhaps a better solution would be a careful measurement of the crank journal diameter and find a piece of brass tubing that diameter inside, cut a piece the width of the hook, and get a machine shop to braze the piece into the hook, thus both strengthening the hook and making it fit the journal correctly. If the added bearing piece is a bit wider than the hook and the sides supported by a fillet of braze, it will bridge the worn groove. The brass (bronze would be even better) will not wear the iron crank as readily. That would be a more demanding but longer-lasting fix.

Or find a machine shop that would make you a hook out of steel bent to the correct shape, to match the length of the Hern hook and make the hook diameter match the crank and wide enough to spread the load across the existing wear. Again, a country farm blacksmith could do this easily and probably cheaper than my first suggestion.

Bob

i had a c&p with a home made wooden treadle, the hook was a piece of old leather belt that was wraped around the shaft, it lasted for years before wearing out.

Thanks for your input Bob. I guess the only thing that’s clear is that there’s no easy solution for this.

@dickg, thanks for your homemade solution. Might be a good option!

don’t see any oil or grease

for about 9 months
have been using the same lash up
Hern + New Style

no sign of wear on the crankshaft
very little wear on the hook

every time i use the press
that spot gets
a big squirt or two of 90 weight gear oil

feel if oil is not on to the floor
under the treadle
am not giving it enough lubrication