Problem installing spring in Little Giant 100lb.

[Quilbilly]

 

I have a 100 pound Little Giant that I am putting back together. I bought a new spring from Little Giant.com and it is 7 1/2” long which they say is for the older machines. The one it replaces is only 7” and I cannot for the life of me get the new one compressed enough to install it. I talked to the folks at Little Giant thinking my machine might be an oddball with a 7” spring but they say it is not.

It is a transition machine serial number 865 and it does not have adjustable toggles links. It does have a spring tensioner which is a big tension bolt going through the toggle arm. But even with that backed all the way out I can’t compress the spring enough. They told me to use a large ratchet strap and I did but it was so tight I was afraid it was going to break and hurt me and  I still had another 1/2” of compression to go. I also tried a pair of clamps on the toggle arms but couldn’t squeeze enough. 

So my question is, does anyone have any tips on installing it. Is it normally this hard to do? And since too much spring tension apparently causes problems, it seems like I am already starting with too much tension. With the old spring in place the machine seems to work pretty good so another question is whether there is a small group of machines that use a 7” spring. 

Thanks in advance for any help.

Todd

[beaudry]

Your toggle arms look short. 

With the spring at the proper tension the toggle arms should be level or pointing slightly uphill toward the ram when the hammer is full down at rest, not pointing down like yours are.

A  spring that is too long is going to make the problem worse , I think. 

 

[Andrew T]

I don't think you will ever get the arms to point uphill on a hammer without adjustable knuckles.

Beaudry does have a point about arm length, it might be worth your time to get some pin to pin measurements from similar machines. Call Little Giant again and ask.

I think Clifton Ralph said he did not like that style of spring tensioner or the single knuckle type, and favored converting to the two knuckle adjuster type. Although I'm not sure why your style wouldn't be fine if the spring fit.

I made new tee-toggles for a 50lber using long grade 5 bolts with the tee welded on, and welded knuckles from bushing stock. Ken Kern shows it in his Little Giant book, which I no longer have a copy of.

Longer arms might give you more throw/power as long as the ram doesn't hit the spring and knock it out into your face.

[Frosty]

I used two bar clamps to install the spring  my 50# LG. It wasn't necessary but it made it a lot easier. By bar clamps I'm referring to the ones that the heel jaw screws onto a length of pipe and the hook jaw slides and locks in place when pressure is applied. 

Safety wire the clamps to the arms and spring in case it slips. You do NOT want a bar clamp launched across the shop like an ugly harpoon! 

Frosty The Lucky.

[Andrew T]

The right arm looks a little shorter than the left in your photo. Measure both and compare length to replacements from Little Giant.

[Quilbilly]

Thanks for the replies. We have been busy with our first grandchild's birth the last few days. As far as the arms being different lengths, they are the same and I first tried the two bar clamp idea to compress the spring and couldn't get it compressed enough that way so I called Little Giant and they suggested the ratchet strap. Like I mentioned the hammer seems to work okay with the old spring I just wanted to replace it for safety. I actually am not using this hammer and plan on selling it so I'd rather avoid making new parts. I was hoping someone would say, "oh some machines just have a 7" spring" and I could cut the new one down with an abrasive saw. I agree with Beaudry that a longer spring just makes the problem worse because when I tightened the old spring the hammer didn't hit as hard. I am still open to other thoughts.

 

Thanks Todd

[Adair]

I have the exact same hammer.  I will check on measurements.  The spring I have was purchased from Little Giant 20 years ago.  

I made a compressing clamp to securely pull the toggle arms together while I pin the toggle links.  I did it once with multiple pipe clamps, but that was sketchy. There are so few surfaces to gain purchase on.  

-Adair

[Quilbilly]

I would appreciate that. If my new spring is the correct length making a spring compressing clamp  seems like a wise idea. Like I mentioned I tried bar clamps and it seemed like a good way to get hurt. Let me know, thanks 

Todd

[beaudry]

Adair, you might consider making a guard for that hammer.Lot's of heavy moving parts going around right there at face level on those hammers.

A simple flat bar frame with expanded mesh panels will provide both protection and visibility. The bolts that hold the ram guide are a good place to attach the guard.

Mock it up with some plywood or cardboard to get the right shape and still have access to all the necessary adjustment and lubrication points.

The guard frame also gives you a good place to mount the pivot points for a  mechanical band brake over the top of the crank plate. 

Here's the one on my 100# hammer

 

 

 

[Adair]

Todd, 

I grabbed a photo of the spring.  As compressed (leaving about 1-1/2" gap between dies at rest) the spring is 7-1/4" long.  It feels a bit tight to me when I'm running hard.  I've worked under at least three other 100# LGs over the years for comparison.  With the clutch fully engaged, it feels like the links are already pulling up on the ram before it has transferred all its energy to the work.  I bet if I could back the spring off just a hair more all would be in order.  

Beaudry, 

I confess, the lack of a spring guard is due simply to laziness on my part.  It's as careless as not putting on a seatbelt.  As for the brake; I did turn my crank plate on a lathe when I acquired it so that I could easily fit a brake strap.  It's on the list.  

 

[beaudry]

If you use your hammer  for hand held top tool work ,a guard around the front of the hammer makes the operation much safer , so you can concentrate on the task at hand.

Keep the bottom edge of the guard as high as possible for maximum visibility . Guards for hammers with nuts at the ends of the toggle arms need  room for a pair of wrenches to adjust the tension.

[Quilbilly]

Adiar, thanks for the photo. I am not near my machine right now but I will compare it when I get back. It looks like your spring must be the 7 1/2" one since in the picture it looks like 7 1/8" after being compressed when installed. And my old sprig is only 7" uncompressed.  So I am inclined to make a clamp to compress the new one and see what happens.   

Todd

[Adair]

Ugly, but it gets the job done.  It can't slip any direction.  The tapered cross section of those toggle arms makes any other clamping solution pretty sketchy.

-A.

[beaudry]

Adair,  looks like an interesting modification to the back end of the treadle in that last picture. Care to explain what's going on there ?

[Adair]

Beaudry,

Ha, it may make the engineerring-minded laugh.  I have always hated little giant treadles.  I made my own that is balanced with minimal slop in the linkage to reduce treadle stroke and the resulting flamingo dance.  

The parts you see are pillow blocks to make the pivot points wide to reduce twisting.  There are twin tubular push rods that go up each side of the frame. They are actuated by a lever that extends from the treadle behind the hammer.  They push up on the clutch arm rather than pull down as the original did.  I built a new clutch arm with a lever running the opposite direction to make that possible.  I love it because the action feels like a large air hammer, but I am not a gifted fabricator.  

-A.

[Quilbilly]

Adair, thanks for the idea of the compressor. I made one and got the new spring in place in a safe and sane manor. But now even with the spring tensioner completely relaxed the ram barely kisses the bottom die. So I was hoping I could get one more measurement from you. That being between centers of the Pittman and the crosshead pins. I think that is the only adjustment left. Thanks. 

[jeremy k]

 

Quilbilly, that measurement can change depending on stock size your working - The general starting point is explained in the info below.

As per page 196 of Richard R. Kern's book - The Little Giant Powerhammer.

[Adair]

Quilbilly,

For what it's worth, 4". As Jeremy K stated, I change the crosshead position on the Pittman as needed.

A.

 

[beaudry]

 Adair,  that looks like a good setup you did on the treadle and linkage.

The factory setup on the  Little Giants  is a little sloppy. When mine was rebuilt, the hole in the frame for the pivot  was reamed to size and a new machined pin fitted so the treadle pivots without noticeable slop . There is also a grease fitting to keep that point lubricated.

[jason0012]

Your link arms are the problem. Originaly it would have had an adjustable arm on one side. The adjustable arms help balance the hammer and make installing the spring a lot easier. I would recomend making replacements for both. They are easy to fabricate and make a big difference.