tympan & frisket won’t clear bar
I’d appreciate y’all’s advice on this one:
We just had a *beautiful* tympan and frisket built for us by Steve Pratt for our Reliance Washington-style iron handpress, which recently came to us without t&p. Come to install the tympan on the press, though, and darned if it doesn’t clear the bar - by a good 3”! That is, when you lift the tympan, the backside corner farthest from the hinge point strikes the bar on its way up (or down).
There doesn’t seem to be anything wrong with the size of the tympan itself, which matches the bed very well.
Here are the salient clues to the mystery:
1. The tympan fits the corner irons and bed.
2. The corner irons fit the bed and look original to it.
3. The bed runs the full length of the rails without obstruction. (We’ve installed some 1/2” thick oak bumpers at the ends, so we could have a half-inch more right travel if we need it. But that only gets us down to 2 1/2” overlap.)
4. The bed seems to fit under the platen as expected, though perhaps 1” to the right of symmetrically.
5. The way the rails bolt to the frame doesn’t allow adjustment. (Besides, if we shifted the rails to the right to increase clearance for the tympan, the bed wouldn’t sit even less symmetrically under the platen.)
6. The press doesn’t show any signs of welding or repair.
What do you think is going on here? We could have assembled the press wrong, but I don’t see how.
Another thing that occurred to me is that the rails might not be original to this press. But that seems like a long shot - they seem to fit it just fine (except they’re too short, perhaps!).
If you have any ideas about what’s going on or how to fix it, we’d sure appreciate hearing them!
Photos attached, as well as here: http://bit.ly/HNRs8B
Miles Kimball
Texas Tech Univ.
front side of press
left end
left end showing how rails attach to frame
right end with bed rolled out to stops
tympan striking bar
clearance of tympan to platen, from off side
right end with bed rolled under platen
front side with bed rolled under platen
clearance, tympan to platen, front side
Forgot to mention, the bar seems to be at a conventional reach and fits the press as expected.
Although I couldn’t see clearly in the photo labeled ‘Tympan striking bar’, it looks to me that you have an excessively long bolt holding the handle away from the lever bar mechanism. If that was screwed in, or replaced by a shorter bolt it would allow the handle to swing back further. The bolt on my Hoe only extends 7/8”, and looking at it from the same angle I cannot even discern that it has threads, unlike yours which looks as if the bolt was either screwed out to it’s full length, or replaced with a longer bolt to essentially bring the handle closer to the operator.
The tympan frame on my press does not extend past the bed like yours as seen in your last photo, which would also account for the parts intersecting, but I don’t think it is the whole story. Your tympan frame looks like it extends 3/4” to 1” further than it should and it needs to be shortened. Shortening the bolt on the handle should make up for the additional distance needed.
Paul
You can bring the bed back by adjusting the rails, just loosen the bolt underneath the press and move the 2 rails a bit back. By adjusting the pressure on the springs, you can release the handle a bit, all this may just bring you ” Home”
The stop bolt for the extended bar is probably the most active factor here — screwing it in all the way, or using a shorter bolt, for maximum “rest” travel of the bar, as Paul suggests, may solve your problem. A slightly longer than usual tympan isn’t helping any. Moving the bed rails won’t gain you much, although removing your wooden stops and adjusting the rest may entirely solve the problem. These presses, while they do often have the hinge half on the outer corner irons, most often were furnished without a tympan. Another place to check, although I don’t think it would make a lot of difference, is whether the use of the other bar hook socket (there should be 2) on the toggle would make any difference. You’ll want to look at adjusting everything possible that can give you a little more clearance to achieve your goal of clearing the bar. Adjusting the spring tension won’t make much difference unless they are very slack.
Bob
I don’t think adjusting the pressure on the springs will change anything. You need to do what Paul said- shorten the stop on the bar so the bar can rest a bit farther from the operator. Look at the toggle mechanism in comparison to others at rest- yours looks like it isn’t able to relax as much as it should!
Daniel Morris
The Arm Letterpress
Brooklyn, NY
As I recall the rails have alignment pins, and the position of the anchor bolt wouldn’t get more than a fraction of an inch adjustment to the rails. The spring adjustments are for tension on the springs which return the bed to open position. You would have to adjust the actual height of the platen which would be done by changing the spacing between the ‘ears’ of the platen and the spring mount on the staple. This would totally change the distance between the platen and the bed, which would have to be made up with extra packing, while again only changing the pull of the handle a fraction of an inch. I would only look to that as a last (and ultimately unnecessary) resort.
The two depressions in the top toggle only affect the downward travel of the platen. In the top depression the platen travels less than the bottom depression, and in the top position the handle rests outward ever so slightly. I would suspect that this is an adaptation designed to deal with the differences in type height, i.e. Didot versus .918. My press was made before American type height was standardized, and this may have been effective later for presses sold to a European market. My Hoe is small, and the toggle depresses easily with hand pressure, but when I disassembled a Reliance it was a major effort to compress the toggle to release the handle.
Paul
Your picture above labelled “front side with bed rolled under platen” makes it look like the tympan frame is about an inch too long. Shorten that, take out the extra rail stop, and adjust the bar stop, and you’ll hopefully be there.
Preston
What is in the ends of the rails? Is there something at both ends keeping the bed from travelling all the way to the end? It could be that there is something there to cushion the impact.
I’ve also marked the bar stop that we seem to agree needs to be shortened or run in more if it is a bolt. On my R. Hoe & Co. presses it is just a plain metal stud.
Do you have the other two corner irons?
Dan
As for the bumpers at the ends of the rails, a piece of hardwood probably won’t absorb much impact. I use rubber furniture bumpers on my presses, and have seen presses fitted with thick industrial felt or cork. If you wish to use wood, a wide, soft-grained wood like pine would allow for some compression. If all of your other adjustments are correct you should have allowance for this on your press. Nothing is sadder than seeing a beautiful press with the ends of the rails punched out from over zealous cranking on the rounce.
Paul
Thanks everyone for your generous advice!
The stop bolt was one of the first things I considered, but if I take the bolt out, the bar can’t move back more than about 1/2” before the ball starts to fall out of the socket. Unfortunately there’s only one socket.
I hesitate to remove the wooden bumpers at the end of the rails for fear that students will knock off the ends of the rails, as Paul suggests. But felt is a good idea.
As to the rails, it doesn’t look as though they adjust at all. I might be able to get 1/8”, but that would be about it. And if I move the rails to the right, the bed won’t be able to go as far to the left and won’t center up under the platen.
We have the other two corner irons — I just had them off temporarily and forgot to put them on to take the pictures. But the bolts of the tympan do extend beyond the corner irons by about an inch. Steve has already agreed to shorten the tympan, but we agreed that something else must be going on.
If we adjust the springs to raise the platen it will give us a little bit of clearance at the bar, but as Paul points out it will also require a lot of packing. Although I suppose I could put the wedge in the platen to see if I could adjust the platen down a bit. The wedge came with the press, but uninstalled. (I’ve never actually worked on a press that had the wedge installed, so I’ll have to figure that out.)
So I guess I’ll go in and adjust everything to see what happens. Maybe cumulatively I’ll be able to get out of clearance that the shortened platen will fit. I’ll keep you posted!
would it be a “bad “idea to suggest that if all else fails, that some of the bed runner where it sits in the rails is removed so the bed can travel further back-but obviously not so far it disengages from the rounce mechanism………..looking forward to a post to say it is sorted….
also——the bar that the handle fits onto could be bent a little so the handle rests further away to clear a tympan??
If you adjust the springs to raise the platen that will also allow the toggle upper piece to move back farther, so it should stay engaged with the bar hook. Increasing the spring tension won’t raise the “on-impression” height of the platen; that is the purpose of the wedge. Check the clearance where the bar hook pivots in the bar — it needs to be free to move all the way to its stop, but if there is paint or some dirt in there causing it to bind that will add to your problem. I would also shorten the tympan past the end of the bed — enough to clear the bar, because while it would be nice to be able to print that much larger a sheet it’s more important that the tympan clear the bar. I would also look at some other kind of stop method for the bed in the rails — the wood blocks, even soft wood, are not enough cushion to prevent breaking out the ends of the rails. Paul’s idea of rubber door bumpers is safer, and they can be thinner.
Bob
Is there some sort of spacer or collar in the spot shown?
If so, removal or reduction of this plus shortening of the bar stop and more tension on the springs might do the trick.
Don’t send this back to Steve just yet- looking at the angle of the toggle parts at rest, this still doesn’t look quite right to me. The platen wants to rise higher.
Dan
If you look at photos of Reliance presses they all have collars in that position, they are part of the spring shaft assembly and are not removable, being welded to or cast into the piece. You guys are barking up the wrong tree. Relaxing the springs won’t affect the postion of the platen, all it will do is alter the return pressure of the handle. Only two things will really affect the position of the handle, 1. the set screw/bolt in the handle, which I think is too long (maybe replaced at some time). It doesn’t look right to me as I am seeing too many threads. 2. The position of the wedge. It mostly determines the position of the platen, but it would add more tension to the toggle and expand the upper toggle some. If the set bolt is too long it would be very difficult to operate the wedge.
I just went out to my press and unscrewed the set bolt to full length, making it almost 1/2” longer. Because of the geometry of the handle this translated to a 1 1/2” difference at the point where the handle meets the rising tympan frame, and prevented my tympan from clearing the handle. If the bolt is too long it is holding the handle out too far. If the tympan is too long it won’t clear the handle.
Paul
I was only suggesting the adjustment of springs if the collars were removed in order to restore the pressure required to lift the platen. If those collars are, as Paul has explained, built in to the spring assembly then I am indeed barking up the wrong tree. On our Hoe presses they are also built in, but are much shorter.
Dan
Remember that when the bar is pulled and the toggle is closed up to its max, the length of the toggle, head to cup, is fixed — you can not change it. That, with the wedge inside the platen under the cup, determines the impression. You can adjust the wedge or adjust the packing, but you can not adjust the toggle length. So you will need the wedge installed to obtain the correct amount of “daylight” under the platen for best impression, unless you want to use a lot of packing. I would position the disengaged bar so the tympan just clears it and then figure out what in the system needs to be adjusted to re-connect the bar hook to the toggle and get an impression from that bar position.
Bob
it may seem crazy??
You say bed sits 1” to the right-is the bed reversible,is it the right way round, can the fittings be switched to the other end and rounce still work, are the bed runners assymetrical or slightly different to allow it to go back further on the rails………
Mystery solved!
After tinkering with many of the potential solutions suggested here (thanks, y’all!), we brought out the wedge (thanks Bob!). I had my doubts, because the cup already extended above the platen about an inch, and I thought it could only move down. It was stuck, so I’d never had it out. After some judicious tapping with a plastic mallet, it finally broke loose. I hadn’t realized the concealed shape of the cup, with its shaft extending down into the platen.
Putting in the wedge lifted the cup, which lifted the lower pivot point in the toggle, which moved the angled member of the toggle out, which pulled back on the bar, and voila! The tympan cleared it. A little bit of movement in the wedge makes for a big move in the bar.
Things yet to do: the pull on the bar is really stiff, so we need to adjust the springs. Plus the threads on the wedge bolt and its female counterpart in the wedge are bunged up, so we’ll have to clean them up with a tap and die. And as many suggested, I’ll need to get a shorter stop-bolt for the bar.
Another thing that just occurred to me: I still have to check whether moving the platen lower so the tympan will clear the bar, makes the platen too low for the tympan to slide under it. If it does, we might still have to shorten the tympan a bit. But probably not as drastically as before.
Anyway, I’m seeing daylight. Thanks again, everybody!
Miles
My one question-
As it is now set, what is the measurement of the daylight you have between bed and platen when the bar is pulled all the way to the nearside stop?
Dan
That occurred to me to check, but only after I’d knocked out the wedge so I can fix the threads. It’s kind of a pain to get the wedge in and out without the bolt, so I’ll probably go ahead and make that thread repair first, then measure.
What should it be, ideally? A certain amount above type high, I imagine, with packing to make up the difference — but how much?
Inserting the wedge raises the cup and moves the bar back — but does it move the platen down as well? I didn’t notice anything except the movement of the bar (after which much celebration ensued — beer *was* involved).
If it moves the platen down below type high + a bit, that’s a problem. I’ll keep you posted.
Miles
Miles, if the wedge raised the cup and caused the bar to move, that is indication that tightening up the platen spring tension would help also — perhaps the platen isn’t rising high enough because the springs aren’t pulling it up all the way. There is a limit to how high it can go, limited by the spring bolt “head” or the flange that bears on the platen bracket hitting the spring bracket (see image). It will also affect the amount of daylight when the bar is “relaxed”, but the wedge is the adjustment for the amount of daylight on impression.
Bob
Platen support spring.jpg
ADLIB, keep in mind the ARM NYC said that the Tension has nothing to do with it :)
Hi Miles - I am in your collection out there..result of “colorprint”…we met at Lynwood’s one evening. I own a Reliance like yours and I built two tympans before I got it right (having a sculpture background helps) but it is a tight fit…when the “at rest bolt” is correctly adjusted, with wedge in..there should be about 1/16 inch clearance between the curved bar and the top cast iron keeper for the spring..Rummonds make a point of discussing these presses since they were designed for printing line cuts and not type and they rarely had tympans supplied and he discusses this very problem. Carl Montford (SVC) Seattle has a wonderful series of pics of his building of a tympan and frisket for this press and there is much to be learned by just looking carefully at his construction…They are great , and very efficient, presses and since they came on the scene later they solved most of the problems… the knuckle is the most efficient answer to pressure.. If you would like images or further exchange of info let me know. I covered my tympan with military Teflon fabric…it is smooth and doesn’t wear…very tough….it just “glides” under the platen with a wonderful whisper when correctly adjusted by the wedge….and doesn’t wear out or scuff up. Ke Francis
Tapped out the wedge and reinstalled everything - looks good!
The resting (“up”) position of the platen puts it at about 1 11/16” from the bed; fully down, it’s at about 1 1/4” from the bed. With type at 0.918”, that leaves 0.37”, which seems like a lot.
Miles, you can adjust that apparently excess clearance of 0.37” with the wedge, but of course that will also reduce the 1-11/16” as well. Or you can make it up with packing. Either way, it seems you’re on your way to printing with it. Great!
Bob
Nice