Metal Shear

[B K]

I recently purchased a floor shear (Gargrave's Shear No. 5) and I am in the process of cleaning/repairing it. Besides being monstrously heavy and hard to move the biggest problem i've had is finding information on it. I talked with the guy who operates the hydraulic shear at the mill I'm Interning at and he said his shear operates with an average clearance of .004". Mine has ~1/8" between the blades when closed. and it isn't aparrent to me how to close this gap besides shimming out one or both of the cutting blades.

Any thoughts on adjusting the clearances or why the clearance would be so large? Maybe set up for cutting hot metal (I did purchase it at a blacksmith auction)? Also any tips on the usage and upkeep of shears in general would be of great help.


More Pics
http://www.uwplatt.edu/~krautkrw/shear2.jpg
http://www.uwplatt.edu/~krautkrw/shear3.jpg
http://www.uwplatt.edu/~krautkrw/shear4.jpg
http://www.uwplatt.edu/~krautkrw/shear5.jpg
http://www.uwplatt.edu/~krautkrw/shear6.jpg
http://www.uwplatt.edu/~krautkrw/shear7.jpg

Thanks,
BK

[Geno]

The closer the gap the cleaner the cut.
1/8" will bend it all, not much cut.
First check the pivot, too much play and no amount adjusting will help.
If the pivot is solid, grind the new edge, shims won't help.
(shims just put more stress on the pivot)
The pivot is where the problem probably lies.
Hope it helps.

[B K]

The upper cutting arm is already tightened down against the base. There is a raised section of the base at the pivot that doesn't allow them to get any closer than they are now. I could tighten it up a bit more at the pivot a bit but that would impede the upper arms motion and wouldn't come close to closing the ~1/8" gap between the blades. I drew a quick diagram that may better explain what I mean. I can't figure out how the gap was ever less than it is now unless the blades are supposed to be wider then they are.

Diagram


You can kind of see this area in pic #6


If shimming won't work them I guess the raised area in the pivot will need to be milled down. Would getting wider blades made to close the gap cause the same problems as shimming?

Thanks,
BK

[Geno]

That would be my next choice, or shim the blades over.

[B K]

When I was moving it recently I noticed indents under the dirt that had accumulated on the wood base. closer inspection revealed several round steel cutoffs burned into the planks. Looks like it was being used to cut hot steel.

[Alden Sherrodd]

I believe that this type of shear should be used to cut flat stock only. It was probably overstressed. In one photo there appeared to be a horizontal bolt with a jam nut on in. That should be an adjustment.

Good Luck

Alden Sherrodd

[Geno]

If there is any adjustment, it would probably be on the bottom side, or stationary side.
See if you can get the bottom die closer by shim or adjustment underneath.
If it was used for hot cutting it may be distorted from exessive heat.
Let us know...

[B K]

I don't believe it's distorted. If I remember correctly the gap between the two blades is pretty even along their lengths@~1/8". There is an adjustment bolt under the cam to adjust the end of the blade arm in/out slightly but it only adjusts the end of the arm under the cam. When I'm home for thanks giving I'll try to snap some better shots. I've been so busy the last year I haven't had a lot of time to do much with it. I did manage to lop off some 1/4" round with it when I first go it home but it was more tear than cut.

Judging by the dirt accumulation and the condition of the wood base it hasn't been used for some time. When I bought it I got the impression that the previous owner never did much with it as he had no info to offer up on it. In any case I think I'm going to attempt to make some new blades of the proper thickness to close the gap if I can get the shop at school to help me surface grind the stock to the proper thickness and cut/mill the bevels. What steel would you suggest for this? Hardness? Some machinists I've talked to have suggested M2 and D2. I have some 5160 big enough but I imagine there are better choices out there.

Any idea where I could find info on capacities? I've searched google for the manufacturer/model# and haven't come up with anything. I suppose if I can try and calculate the force the shear can impart at the cutting edge and compare this to other shears and their listed capacities.

I've been looking for shears better suited for thicker bar stock or rounds but haven't come across many manual ones.

Thanks

[birdog4]

I have a similar shear made by the Buffalo Forge Co, Its stamp says it is a T and Angle cutter. bruce