More Cleaning & Painting

I took off the ink plate support braket, cleaned and painted it. The disk advance leaver as well got the same treatment. As I was working on that I realized that it is easier to shim the whole braket up (to make up for the ink disk machining hight loss), then to make a bronze disk to put on the disk journal. Then I takled the rear of the press bed (under the ink disk), with those deep pockets formed by the web of reinforcing bars. That area is a real trap for dirt and junk and is also the place where I have found the worst scaling (likey from the original casting process).

After yet another night of cleaning and painting the rear and sides of the press bed are painted. For a while now I thought the paint I'm using (Tremclad dark blue) was too soft. But I'm changing my mind on that. The first items I painted more than a week ago now are getting harder every day. I was worried about being able to wipe oil of the surface if it stayed relatively soft. And I'm getting used to the colour as well - I thought that it was too light, but it's nice to be able to see all the parts even when the light is not right on it, and also I'm just getting used to it.

A New Surface on the Ink Disk

Tonight the ink disk got machined. There was significant run-out, although not as bad as it looked when we put the straight edge across it. There is something about the light coming through that little gap formed by the straight edge and the surface being checked that really amplifies any error.

The gap looked huge, but on the lathe with a dial indicator it "only" measured 0.020". In any case, to get a decent cut and a feed rate without chatter resulted in 0.030" being taken off the ink surface.  A big deal was to have secondary support at the ratchet ring to the lathe chuck. Before that the cutting tool action on the disk was just screeming with vibration. The surface is not perfect, but it is perfectly flat and I can polish the rest in position on the press. Now I've got to get myself a machinist straight edge so that I can measure if the disk sits too low, and if I have to make up a bronze washer for the bearing to bring it up the 0.030" that it was sitting higher before.

Finally Moved Inside

After a bunch more moving stuff around, throwing stuff away and recycling - the press is inside! Its mot pretty, and there is a lot more stuff that will have to go, but it's inside before the snow!


And if that is not enough, the first piece has been painted. I took off the ink platter, cleaned it and painted the under side.
The top side will take some more work. When the press was shut down and stored something was left on the platter - it was likely ink - and that has eaten into the surface. The Scotch-Brite pad on the die grinder is cleaning it up but there are quite a few pits left. So I took the sanding disk and tried to get more agressive in polishing the marks out. I'm not happy with the results. I'm going to look for a machine shop to grind the surface on a lathe so as not to remove too much metal. But its a start!
 

I found a machine shop, but that started some real concern: We put a straight edge across the ink surface and discovered either the platter is seriously distorted - or it is supposed to be crowned (the center being sone 3/16" higher than the sides). I will have to wait until it is put on the lathe before we can be sure. In the meantime I'd appreciate if anybody can check their C&P ink platters to see it they are crowned or really flat?

A Better Tool

What a difference a better tool makes! I visited a machinist tool shop and came a way with an air operated die grinder, a disk mandrel and a selection of sanding and cleaning disks. The tool runs at 20,000 RPM and does a real nice job of cutting through surface rust. So far I have only used the polishing disks, I really don't want to take off metal unless I can measure the results.

Now I just have to deal with the fact that my air compressor is waayy too small to power the tool properly. Right now I have to wait 30 seconds, make a pass, wait another 30 seconds and so on.
What I really went there fore is a machinists straight edge, so that I could check the bed and platten for straightness. They did not have those in stock and I got talking with a real helpful guy behind the counter and I came away with this real fine tool. Now I'll have to rent a better air compressor for a few days.

When do you stop?

It has been cold, and the progress of getting the place for the press clean is slow. But there was a good day a few days ago and as I looked over the back side of the press I felt that some good cleaning would be all thats required. After all, what could be wrong with the simple spring with the attachment to the chase clamp and handle? And with all that grease and dirt on it, it would just jump like crazy when I got it off - and who knows what a pain it would be to get the spring back on after.
But then some sort of a guilt mechanism clicked in place and I removed the spring attachment to the handle, and then the handle hinge bolt. Sure enough the spring jumped around just to prove me right. After cleaning up the spring though, here is what it looked like:

I'm sure glad I took it apart, it's worn almost half through! When that spring lets go the chase is loose in the press - that would make a mess! There is a lesson in that.

Anybody Need a Motor?

The motor that came with my press:

It's for sale!
Offers?

Saddle Post Spring Detail

Turns out there are two different springs. one. the shorter one for the double saddle post & rod:
Length 31", 190 turns of 0.079" diameter spring material, wound to 0.465" inside diameter (0.620" outside diameter).
The longer spring is for the single saddle post & rod:
Length 34", 196 turns of 0.070" diameter spring material, wound to 0.467 inside diameter (0.608" outside diameter).

To be able to get the spring off the rod you need to be able to compress the spring a bit while removing the cotter pin at the end. I found a pice of 1/2" PEX pipe (for residential water pipe use) handy as it has just the right inside diameter and enough wall thickness to push in the spring. Once you get the pin out and release the pressure on the spring be ready to have the spring jump right into your face. A set of leather work gloves on your hands go a long ways to contain the spring force, letting it go more slowly.

Notice that on one end the springs have a little straight tail, that is the end near the saddle post (keeps the spring from yurning).
 
It'll be fun  getting the springs back on...

More Rust, Dust & Gunk Removal

For a few days It's been very cold. Since the press is still out in the driveway I haven't got much done. Today was a good day. Worked most of the day on the press, removed the saddle stud & rods and the gripper bar. Noticed a difference between the double saddle stud and sthe single one. The double saddle stud springs are shorter than the single saddle springs. I wonder if that is because the single saddles were not used on the press (by the previous owner), thus never got compressed or cycled? Or is there a technical reason for it? Tomorrow I will measure and document the springs. Made good use of degreaser and cleaners today. The platten cleaned up real nice with the rust remover.

Made a decision on the oil holes today. While I have things appart anyway I will redrill the top part of the oil holes and get oil hole covers to try to keep these locations from accumulating dirt, and make them more obvious for long term maintenance.

Interesting Encounter, Speed Calcs

Had an interesting encounter today at the farmers market. When I was looking to sit down to enjoy my danish and espresso, there was no table free. So I shared a table with an older couple. We got to talking about things and surprize surprize the gentlemen used to feed a C&P letterpress many years ago in a little town west of Red Deer. I asked about the speed and he insited that they were doing about a hundered pieces a minute top speed. Hm, that seems a lot. The other production number I have heard a few times is about 2000 impressions per hour (iph).

I am going to aim for half of that, 1000 iph. My press has a 24" diameter drive pulley. The smallest I am likely to get for the motor side pulley is 2" diameter. So that works out to a 12 to 1 speed ratio.

Here is a picture of the press as it arrived, with all the ties and chains removed, free at last.


With 7 turns per impression on my press, that is 7000 rotations per hour, or 116.7RPM. On the motor side that is 116.7 times 12 = 1400RPM. For an 1800RMP motor, operating at 1400/1800 = 78% speed of maximum is not that bad, but there is something else I have not mentioned before. I would like to increase the time available for the paper removal and placing task (while the platen is open) by manipulating (reducing) the drive speed depending on the press position (when the platen is open). During the three truns of the drive wheel while the platen is open I'd like to reduce the drive speed to about 40% (for a 1800RPM motor that would be 720 RPM). And during the four turns while the platen is closing/opening I'd like to run it at full speed. My press was equipped with a 1800RPM 1/2 HP motor, I have the original motor but not the motor pulley. My plan right now is to use an inverter duty 3/4 HP motor and VFD to be able to handle the cyclic acceleration/deceleration.
An 1800RPM motor actually runs at about 1750RPM at full load. Assuming that it will take half a turn (on the press) to accelerate from 720RPM to 1750RPM, and half a trun to decelerate back to 720, that makes one turn at an average speed of (720 + 1750) / 2 = 1235RPM.

So here is what my prediction is for overall rate:
3.5 turns at 1750RPM (at the press that is like running at 1250iph)
2.5 turns at 720RPM (at the press that is like running at 514iph)
1 turn at 1235RPM (at the press that is like running at 882iph)

Working out the average speed for the time weighting that each speed applies:
(3.5/7) * 1250 + (2.5/7) * 514 + (1/7) * 882 = 934.6 iph average speed, pretty close to the 1000 iph I was aiming at, and I gain a safety advantage with long platen opeing time. Let's see what that would actually work out to: 720RPM / 12 is 60RPM at the press, that is 1 rotation per seconds, so for the 2.5 turns the platen is open - that makes it 2.5 seconds. Plus the bit of time the drive is speeding up and slowing down. So maybe close to three seconds time for the paper shuffle. That seems lots. We'll see! One other feature I have been thinking about is to have two buttons on the feed table that have to be depressed before the press will return into the high-speed mode (or possibly if they are not pressed bring the press to an emergency stop via dynamic breaking). If anyone can think of holes in this reasoning, I'm open for suggestions.

Some Days are Easier than Others

Today was another day of rust removal. Now my order at Acklands came in and I have better emery-cloth and some rust remover to try out. Had bought a new set of wrenches at Home Depot, an open end - close end ratchet combination set in the typical heavy plastic packaging that you need a set of shears to open. When I came to use the 9/16" wrench I find the ratchet did not work, and looking at it closer it was a used wrench of a sightly different style (still a Husky). Back to Home Depot for a refund, but that was not so easy. Even though the packaging claims lifetime warranty there was a lot of waffling going on, I felt they were of the opinion that they were letting me get away with something. Frustrating.

Here is my friend Tom at the top of Rogers Pass, with the press in tow.

Then a slight, could have been bad mishap. I had attached the thow-off leaver linkage and left the lever pushed forward. Then I worked on cleaning rust off the platen and the tympan bale areas. I left the top bale folded down while I got busy with something else. As I turned the flywheel cleaning the main rocker shaft I felt a bit of resistance on the flywheel. Hm that's not right. As it turns out there id just the right amount of extra space left in the throw-off position so that the bale just gets squeezed a bit - without damage.
 
Note to self:
1. Never leave anything on the platen that could cause damage.
2. Always turn over the press for a full cycle by hand, and check if anything seems to take too much force!
3. Never leave the platen bales open!