# Home Built Press With Robust Clamp Registration



## mrobsessed (Sep 30, 2007)

Hi All,

I've recently finished building my long-planned four-colour one-station press, so I thought I'd share some details of what I've made and how I did it.

I'm just starting out in screen printing and wanted to give it a try without having to spend a lot of money to get set up. Having already built an exposure lamp (see another thread from myself) the next step was to construct a press that would hopefully be able to handle up to four-colour jobs and have a registration system that would be very solid and not loosen with use and wear. Also being not very good at carpentry I wanted something that could be fairly easy to build and also able to be dismantled to modify later if needed.

I had seen a few designs for simple carousel presses (usually four colour) that looked fairly easy to build but I was not satisfied with the 'peg and hole' registration systems that were used to hold the carousel turntable in each of the four printing positions. These looked wobbly and such a system is bound to loosen with use as the peg and hole wear. I settled on a clamp system that could be tightened, firmly locking the carousel into each position and would not wear with use.

I'll just show the pictures and explain each of them as I go - this is pretty much the order in which I biult the press though I dismantled it after it was finished to get the photos. Apologies for the poor quality of the photos they were taken with a low quality phone camera under yellow safe light darkroom conditions.
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Pic 1 Base Board Underside*










This board supports all the parts of the press - the picture shows the underside, the carousel part of the press and platen board is not attached.

*A: The platen arm bolt and nut*
This single nut and bolt holds the entire platen arm rigidly in place by compression - the nut visible in the picture has been highly tightened and there is a big washer underneath it to stop it digging into the wood of the board. The bolt itself is a hefty 200mm (8 inches) M10 (10mm) machine bolt. The platen arm assembly it supports cannot be seen in this picture.

*B: The Clamp Arm*
This has the registration clamps attached and is firmly fixed to the board by numerous screws from the board side (just visible). The Clamp arm like most of the wood in the press is square section planed 44mm softwood. This beam also holds the turntable bolt in position (not visible).
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C: The 2 Registration Clamps*
These are what holds the turntable in each of the four printing positions. They are attached to the clamp arm by 150mm M6 carriage bolt, washers and thumbscrews. The clamps swing freely on the clamp arm and so in this pic they are hanging towards the floor.

*D: Baseboard Beams*
These are just to add rigidity to the base board - they are each attached to the board from the board side by 5 50mm screws. These beams also give clearance for the platen nut end to sit in between the board and the surface it sits on. These beams are also 44mm square softwood.

The board itself is 47 inches long and about 18 inches wide, it is made from plywood and is about 15mm thick.
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Pic 2: The Baseoard Top*










*A: Castors*
These support the (considerable) weight of the turntable section and help it to turn easily and smoothly, acting as simple bearings. They are slightly higher than the top edge of the clamp arm, so anything sitting on them has a clearance of a few mm above the arm. The castors are mostly arranged to be the same distance from the point about which the turntable rotates and are positioned so the castor wheels point along an imaginary circle from this point. The castor wheel housing can rotate in any direction (like a shopping trolley) but the movement of the turntable moves the wheels into the correct orientation when it is rotated. The castors are normal screw-on furniture fixtures bought from a high-street household supply shop. The middle castor of the right-hand group of three is not in a circular position like the rest but this does not affect its operation (I had four castors to start with but added two more to better support the weight)
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B: The Turntable Bolt*
This bolt holds the turntable in position and keeps it pressed firmly against the castors (not too tight or the turntable is hard to move!). The nut end of the bolt is countersunk in the clamp arm where it touches the base board. Enough countersink space was chiselled out so that the clamp arm can sit flat on the base board without the bolt head getting in the way. Obviously the bolt was installed in the clamp arm before the clamp arm was attached to the base board! The Bolt is a 150mm (6 inch) M6 (6mm) carriage bolt. Try and drill the hole for the bolt in the clamp arm as straight as possible - use a bench drill if you get the use of one - the bolt should be as vertical as possible.

Again in this pic you can see the loosened clamps have again swivelled around to point towards the ground when the base board was turned over.

In all these pics the press is sitting on a work bench as a temporary support!

I'll post the rest of the pics over the next few days - hope this has been of some use so far, feedback is appreciated!


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## Sheepsalt (Sep 12, 2007)

Very nice! Can't wait to see some shirts come off this thing. I dig your ingenuity.


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## A Perfect Pixel (Jul 4, 2008)

wow... pretty impressive rig there...

are you finished with it yet?


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## mrobsessed (Sep 30, 2007)

Thanks for the comments.

Yes the press is complete and I've printed some shirts successfully.

So far it has worked very well and been useful. It took quite a while to construct (2-3 whole weekends or equivalent) but was not too hard. Hopefully this guide will allow others to give it a go too!


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## mrobsessed (Sep 30, 2007)

OK I'll continue with part 2 of this thread where the platen board arm will be added.

*Pic 3 The Platen Arm*










This pic shows the other end of the of the base board and now you can see the platen arm (A). The arm is open at the front of the press so the platen can slide off the arm and be removed or replaced.

As mentioned previously, the platen arm is attached in a very simple manner, with a single 200mm M10 bolt, washer and nut. The Platen arm and the two shorter pieces of wood that support it (C) just have a hole drilled through them large enough to for the bolt to fit through and the base board is drilled through in the same way.

The wood is all cut from the same beam of hardwood and I had a local timber yard cut this to be the correct size (50mm square) so the platen bracket would fit (as discussed later). I was lucky enough to get some hardwood that was 50mm by 70mm so I just had the timber yard chop 20mm off one side of the beam.

I actually fitted the platen arm after I had finished the turntable so a screen mounted on the turntable would be correctly positioned on the platen.

The 'stack' of wood A, C and the base board are kept in position solely by the pressure of the bolt so partially tightening and then adjusting the platen arm to be correctly positioned along the centre the base board is important. Once the platen arm and support is correctly positioned the bolt can be tightened fully - once this is done the platen arm is rigid enough to stay firmly in position.

If you prefer you could screw and/or glue the platen arm and its mounting together but in practice this is not needed. Leaving the platen arm assembly as a loose stack of bolted pieces of wood gives another advantage - the bolt can be removed and the mounting pieces (C) can be replaced with pieces of different thicknesses making the height of the platen board above the base board adjustable. A number of thin pieces of hardboard with a bolt hole drilled in them could also be used to give a fine degree of height adjustment to the platen arm by adding and removing them from the stack. The platen arm retains all its strength and rigidity when the bolt is replaced and tightened - care must be taken to check that the platen arm is re-centred every time the bolt is removed.

The bolt head is recessed in a small square hole which I chiselled out of the top edge of the platen arm so it does not get in the way of the platen board which sits on and slides along the same flat top edge. This can be seen more clearly in another picture. The position of the bolt through the wood is indicated with (B).

the heads of some of the screws that hold the base board beams in position are marked with (D).


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## mrobsessed (Sep 30, 2007)

*Pic 4 Turntable Base*










Next comes the lower part of the turntable.

This consists of a square piece of plywood - in this case it is 23.5 inches square but this large size caused some problems which I had to fix later.

The reason I chose this size was so that when four screens are mounted on the turntable there would be enough room for them to be folded vertically and not get in each other's way. In practice I think a smaller octagonal board would have worked better and I was later forced to adjust the upper turntable to a more octagonal shape due to problems caused by the large size of the turntable. 

The base of this board is perfectly flat except for the screwheads that hold the 3 clamp beams (C) in position. This board sits on the Castor wheels and a hole drilled through the centre of the turntable base board and the long central clamp beam fits onto the turntable bolt. A washer and a nut holds the turntable firmly on the castor wheels but loose enough so that the turntable can be turned easily (A). 

It must be mentioned that the turntable construction must be accurate. The clamp beams must be central to the board they are mounted on, the board must be square and the central bolt hole must be as central and vertical as possible so accurate and careful measurement is needed. 

The two shorter clamp beams (C) are added to the base board and more than anything else the four protruding ends of these beams must be accurately positioned in relation to each other and the board they are mounted on.

As you can see in the picture the clamp beams jut out beyond the edge of the board they are mounted on by about two inches. As before this wood is 44mm square section softwood. The protruding ends of these beams fit into the clamps and this is what holds the turntable in position of reqistration for printing.

These beams need to be firmly and rigidly attached to the turntable base board so the whole turntable does not move when it is clamped down - they are attached like the base board beams, screwed from the board side by a number of 50mm countersunk head screws. 

In the photo the near clamp has been flipped up and tightened onto the clamp beam showing how the clamp mechanism works. The clamp on the opposite side is not engaged and hangs down towards the ground out of sight.

Once one of these clamps is tightened the turntable must not move at all - it must be as rigid as if it was nailed to the base board!

The remaining pieces of wood on the edge of the board are just support pieces that the top part of the turn table sits on. I didn't put wood all the way around the edge as this was not needed and saves some work and materials (even if is does unfortunately result in a disturbingly swastika like appearance).

Like the other beams these are attached with screws from the board side. The screw heads on the underside of the board - that rolls on the castors - can be positioned so they avoid the castors, screwed so they are roughtly flat (flat head screws) or filled with filler. In practice they do not affect the operation much. 

E shows a better view of the chiselled-out space for the platen arm bolt head.

The four holes in the beams at the corners (one marked B) are for the bolts that attach the top of the turntable onto the base.


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