Repairing Little Giant guide wear

[fciron]

Hi all,

I've got a new style 25 lb. Little Giant hammer. I was doing some maintenance and tuning and I bought a new set of dies from Sid at Little Giant. I have been monkeying around with various found and homemade ones and decided it was time to get the right ones in there. I adjusted the guides to get the dies parallel side to side, but there was a gap between the dies in front.

I measured the dies, and the sow-block and they are all square and true. Then I pulled the ram, and it seemed to be square as well. Continuing to work outward from the problem led me to an answer I really didn't want. The ways in the frame are not square with the dovetail in the base.

This kind of makes sense, the top of the ram is getting tugged back and forth each cycle. It's also possible that doing lots of drawing at the front of the dies pushes the top of the ram back. On the other hand, the ways seem flat, not wallowed out like I would expect from wear, the surfaces on the ram and guides seem nice and straight too. The finishes are good too, no gouging or other signs of abrasion. Whatever the cause, I've got a problem.

It seems like the quick fix would be to grind the top die to square things up. (I'd have to remove about 1/16" from the back edge.) This would not bring the movement of the ram square to the bottom die. I can't thing of an immediate problem with this, but it just seems wrong.

The other option is to try and bring the ways on the frame back to square; either by grinding it back, adding a gib (brass or steel strip), or both. I don't have the machining equipment to do much of that, so it would be lots of angle grinder work and I fear that even my best efforts will leave it less flat and true than it's current state.

The more I think on it (as I write this) the more I think I'll just grind the die, but I'm still open to suggestion. I'd like to make the most informed decision that I can.

Thanks,

Lewis

[peacock]

STOP DO NOT grind cut or remove any metal from your hammer. you could have many other things causing this problem.
Is the bottom of the dovetail in the sow block flat? If it is put the die in and look at it the die from the end. Is the bottom corner of the die hitting the corner of the dovetail on the side opposite the key? If it is take it out and grind the corner off the bottom of the die so it doesn't touch in the corner. If it was hitting the key can rock the die up causing the afore mentioned problem. now make sure the key does not have the same condition. You can also have the same problem where the sow block mounts in the frame. Now go thru the same process with the die in the ram. If this is OK and you still have the problem remove the ram. If you have flat dies you can easily check if the die face is square with the back of the ram surface with a good square. Now with that done use the square to check the top of the bottom die with the front ram guides on the hammer. If you have found a problem in any of these things post again and we will try to come up with a fix.

[tdaleh]

did you ask Sid at little giant about this problem.

[fciron]

did you ask Sid at little giant about this problem.

Just got the dies Friday. I'll be calling Sid in the morning. (It's Sunday now.)

[Dave Hammer]

If your dies are only a 16th of an inch out of alignment, they are probably better than 90% of the hammers in use.

But.... If you have to have them perfect....

Do you have a spacer on one side of your lower die and a drift on the other? If so, you can solve this problem by tapering the spacer (to align the dies) and modifying your drift to fit the new angle.

If you don't have a spacer, make a spacer for both top and bottom dies (bottom spacer tapered...lining them up), then make new drifts.

[fciron]

Dave,

Thanks for the suggestion, but it's a vertical misalignment. If I put a piece of flat stock between the dies then the back edges touch and the front edges do not.

I thought about tapering the wedge and spacer vertically, but I'm pretty sure that anything that keeps the dies from sitting flat on the bottom the dovetail is a bad idea.

I'm guessing from your 90% statement that you don't think that having the ram come down a little off plumb will make a difference to anything. I can't see a big problem with it, especially front to back, a side to side problem might cause a tendency to forge a rhomboid/parallelogram.

I do want it as close to perfect as I can get. It's important for the edges of the dies to match up. Much, probably most, of the work we do on power hammers is drawing and if your dies don't match then it's difficult to draw straight and square. You can straighten at the end of each heat, but often there is also a slight diamond cross section in the bar and that can show up when you make a scroll.

For what it's worth, I use flat dies with a radius on the edges which I find to be the most versatile set up. The radiused edge is good for drawing and flat dies are best for tooling.

[harrismetalsmith]

FC
I had the same exact problem when rebuiding my Nazel hammer. The ram dovetail was not square to the ram by
3/32". I had a machine shop mill the bottom flat, and the corner of the dovetail I finished with an angle grinder.
You could do the entire repair with an angle grinder, just keep checking it as you go. I believe my hammer got worn this way from years of pointing work done with a tapered bottom die, which caused more wear on the back of the dovetail.
Be sure to not get the corner of the dovetail to sharp, as this could promote cracking over time.
I love to keep things original, but if original is screwed up, fix it right.
Good luck!
Matt

[Dave Hammer]

I should have asked... I assumed your dies were mis-aligned side to side...

The dies should definitely meet top to bottom without daylight. If they are out, even as much as you describe, your work will want to move in directions you don't want it to.

Talk to Sid and see what he recommends. I would grind one of dies to match the other.... Then smooth to the finish of the other die with sanding belts and polish.

[firefarm39]

One thing to check for is if your sow block is in backwards. Sow blocks on newer LGs are seperate pieces and are held in place with tapered wedges just like the dies. This often creates problems with dies lining up.

[fciron]

Thanks for all the input. I've checked the ram and the sow block and the issue really is that the ram guides at the front of the hammer lean back.

I spoke with Sid this morning and he agreed with my analysis. He said it might have been that way all along and no one noticed because it shipped with drawing dies. (It had drawing dies when I got it and I've been using a bunch of mismatched hand-me-downs, so when stuff didn't fit I blamed the dies.) I also remembered later that I dropped this hammer while moving into the shop, so there's any number of possible explanations.

After dropping it once, I'm not moving it back out and sending it to Sid to have the guides machined. That's a long darn trip, too. So we decided the best bet is to grind one of the dies to match.

I decided to grind the bottom die so that the motion of the ram will be perpendicular to the work. (The bottom die isn't level now, so that won't be a new problem.) If I ground the top die then the motion of ram would still be at an angle to the bottom die, which might cause unforeseen issues.

Thanks again for all the input and Sid at Little Giant was very helpful.

[peacock]

Sounds like the right fix to me. Sid is a great resource and an even better guy.
rough grind out of the hammer, then install in the hammer. Grind a little, put a piece of paper on the bottom die take a light blow with the hammer, paper will show where to grind.

[fciron]

FC
I had the same exact problem when rebuiding my Nazel hammer.

whodathunk my little 25 would ever have anything in common with a Nazel? B)

[Dave Hammer]

What Peacock said....

and good luck...

Incidently... There is commonality with all power hammers. Folks like us. That's one reason this community is a great thing to be part of.

[fciron]

Oh, I got the die ground down last Thursday, so the hammer was running for Friday forge day. (I light a fire and hit something whether I need to or not, just to remind myself I'm a blacksmith.) I tapered some square that gets scrolled into curtain tiebacks and flattened a rusty lump from the scrap pile just for fun.

With new bushings in all the arms and links, a new belt and new square, flat dies it sure is a nice little hammer. I think I might concentrate on rebuilding the 50 that came with the shop and quit dreaming about new hammers.

But first a new gas forge!