Coulter discs

[henk]

On my Ford Ransomes EPJ plough I would like to assemble new coulter discs. For this, I bought 16-inch discs at a Dutch supplier. These are the same that provide Old20 and Westlake and correspond to the original Ransomes discs.
The discs are normally riveted to the axles. I’ve done this twice in the past by warm riveting. It gave no problems.
The disks I have now been heat treatment hardened and at the slightest heating they warp considerably. So warm riveting is not possible. After much searching I found a type of steel that is soft enough for cold riveting, but this way also deform and warp the discs.
I’m getting a bit frustrated about it.
Does anyone have experience with this and what can I do to solve it?

I know that bolting them on is not the right way, but I’m thinking of making a clamp disk with three M10 thread holes and put that in front of the disc and put the bolds in at the axle side. By using LocTide I can hold the bolds in place. Hoping that the discs are staying flat.
Would this work?

[oehrick]

Hi Henk

Do the disks fit the centre properly or is there a gap between them and the face of the centre ? If there is you may need to turn the face of the centre to fit the disk or make a shim to fill the gap.

If not, I can't see why they should distort with the rivets, if they distort with this little force they may not last long in the ground

Also if they distort I wonder where and by how much they have been hardened.

Retainer grade of loctite (and possibly studlock) should hold well enough if you go the nut and bolt route, make sure threads on both are completely grease and oil free and do not over torque the nut otherwise you squeeze all the loctite from the pressure side of the thread and almost half the strength of the joint.'d be inclined to take these 'just like Ransomes' back to the supplier with the centres and get them to show you how to do it 'just like we always did with Ransomes'

HTH and you didn't get any damage from that wind we had last week

Just a thought, are you heating the whole lot up when hot rivetting or just the rivets ?

Rick

[henk]

Rick,

There's some space on the center hole. The disk winds not over the circumference but sideways.
I think there is a lot of tension in the discs. That does not mean that they break easily.
The two times I've done it before, I have heated only the rivet on the stem after it was put in the hole with stem to the shaft side. I had to warm up then twice to make the rived head.
Now I've done the same thing the first time, but warmed the rived stem to the disc side. This made the disc very crooked. The second attempt I did as before. Then also the disc was crooked, but less.
I have done several ways with a dummy from warming to cold riveting and I have also done it with a 10-ton press.
The last attempt on the disc, I have done it cold. Now the disk did not bent to one side but he swings around to the sides by about 7mm.

This is what I had in mind.



We are used to a lot of wind from the west. All weak things have already been selected in previous storms so there is little damage. Storm from the East makes a lot more damage. I think the wind was a little less than you. We had wind 9 to 10.
There are always fools, who needs to ride, with a trailer, caravan or an empty trailer truck on a bridge, whilst being strongly discouraged and they are giving the most problems.

[oehrick]

OK Henk,

If the inside of the disk is flat onto the flange face of the hub with no interference in the bore then the problem has to be in the material - are you putting two well fitting bolts and nuts in the two holes when you fit the first rivet ?

Have you had the hub off its shaft and on a lathe to check for run out and perhaps a skim from the face ? if the previous disk ran true probably not going to help much but at least you would know you start with a plain face.

There are sometimes problems from heat treating & plating 400 - 700mm slicing blades for some of our machines (bacon, salami cheese etc cut at around 2000 slices per minute ) and the section that makes them employs a man retired from a circular saw blade factory who hits them with a hammer to equalise the tension, not many hits, he gets 0.5 euro per hit plus 50 euro for knowing where to hit . If nothing else you could try a 'saw doctor' after fitting if there is still run-out at the edge.

Your bolted housing idea looks fine and is easily serviced in the future.

Know what you mean about the IQ0's olice had to warn stupid spectators way from the areas of the coast here last time we had a surge in prospect - have you seen the 'Darwin Awards'? people so stupid they have killed themselves in some idiot way so have removed their genes from the human gene pool - so far I've avoided an award

Best of luck with your coulter

[henk]

I had them on the lathe and the surface is dead flat. And I put bolds and nuts in the other two holes when riveting. The only thing I can come up is that the power from the rivets is diffenrent.

I've tried to flatten the first disk with heat and cold bud knowing were to heat and where to cool is the secret. The same as hitting it on the right place.

Ik will grind the rivets of and see what happends when bolting.

Thanks for your comment and help.

[oehrick]

You seem to have covered all bases Henk - I know from previous discussions that you are no amateur at machining & metalwork so if it is mating to a true flat surface and there is no interference from either rivets or bolts it has to be internal stresses that are being disturbed by the localised heating or loading of the fixings. Hot rivetting is immensely strong as witnessed by steam boilers, bridges and ships from before the welding era.

At least, if you have missed something obvious, having shared it with us, we have missed it as well.

I think your best bet is to loctite the back face and bolt it on, only doing the nuts up until it distorts then back torque off a little until it runs true, I know Loctite is not traditionally used for flat surfaces but I have used both retainer and bearing fit grades in this sort of application on both cast iron and stainless steel with good results - let it cure horizontally so it doesnt drain out and I generally use a little heat to improve the cure - hot air gun rather than gas torch, a Henkel rep told me to spit on the item and if it spat back, it was too hot (i.e. keep well under 100C 8-C should be OK)

Good luck and may your furrows be forever straight