Thread: Darfting table mechanism failure!

This was a common problem with these tables when purchased second hand. It usually meant the table had gone over backwards and bent the ram.
If the stiffness is gradually getting worse, it is more likely to be a lubrication issue.

Thanks Rustynail. The problematic one came with the problem. Yes, it was purchased secondhand. My Bieffe T2 is so well-behaved I thought purchasing a Bieffe 2 in apparently very good condition would be OK. I've never heard of that problem before or of them going over backwards but with this one I can see how it could happen now as it needs two people to change the height/angle. It's been bathed liberally in WD 40 without any improvement. As noted I can't locate a manual and the manufacturer hasn't answered my emails. What/where is the ram, please? Can it be straightened, if this is the problem? Is there any hope for it as it can be repositioned and locked? it's just an almighty struggle that I can't accomplish alone. I look forward to clarification. Thank you.

Going on a guess, the "ram" to assist lifting is possibly a gas strut. You'd need to pull it apart to see for certainty. I know if a gas strut bends they can be problematic. The stiffness of the table top could be some damage to the metal adjustment brackets, doesn't need much to cause a problem. Undo the pivot bolts a bit to see if that eases the situation.
Kryn

Thanks for the input, Kryn. I don't think it's a gas strut. I could be wrong. Peering down the innards of the leg with a flashlight doesn't reveal anything other than what appears to be a cam. The pivot bolts have been loosened with no improvement. Even when the foot brake is in the "off" position the board is still difficult to adjust. I'm so disappointed as the height would be perfect, if it worked, as I need to work with the board horizontal sometimes and the T2 is too high in the horizontal position.
Thanks again

The ram is the back most arm under the table. It will be in a near vertical plane. When an oversized pento is fitted to these tables they have a nasty habit of going over backwards, due to the short rear length of the feet. A too heavy light will cause the same problem.
Once the ram is bent, the triangulation of the mechanism is compromised causing resistance. By removing the ram and straightening it, the problem should be fixed. May be a good idea to check the other members for straight as well while you're at it.

Thanks for the clarification, rustynail. I did examine all the components and how they related to each other but I'll check again now I know the possible culprit.......don't know what an oversized 'pento' is and can't find any reference.....an oversized board, maybe?

Ian, I'll post some pictures when I've looked up how to do it.

I guess everyone has figured out the thread title should be 'DRAFTING' Table, (not Darfting)

A "Pento" was a rather heavy in design drafting machine. Hardly ever see them these days. They were capable of being duel purpose as they could also be set up as a pantograph for copying. Way too heavy for the average drawing board and that's why the boards would go over backwards.

Huh! I've never heard of that brand. Thank you. Just had another look at the drafting table. All seems true and parallel but I'll take a tape measure to it to be sure as I'd like to solve this problem. As mentioned the height is perfect and if it behaved like the T2 table it would be ideal.

You need to test the mechanism components with a straight edge. Particularly the ram.

Thanks again, rustynail. The components all appear to be straight.

The seller kindly came over and was able to release the foot brake quite easily and with a bit of effort was able to adjust the position of the top. (He does have leg muscles like a marathon runner's.) He assured me that is how it was when he used it. It had been in storage for about ten years so maybe the WD 40 has now penetrated to some of the stiffer parts and the top is fractionally easier to move now.

I also feel puny and weak! I still can't operate the foot brake with my foot but by recruiting a walking stick left over from an old injury and reversing it can lift the brake with the handle (rather like a shepherd's crook). That is a simpler solution than the gizmo I was designing to release the brake by stepping down rather than trying to lift up. If it doesn't free up any more I will proceed with a 'lift assist' device. It also seems that it's necessary to reach in further to release the brake on this table, meaning it's necessary to bend the opposite knee, weakening the stance, probably because the table is lower. With the T2 I could lift the brake without bending the other knee. The board can't be mounted any further 'in' or it will be unstable. I'll persevere now that it can be adjusted, albeit with some difficulty.

Thanks all for the input. It's appreciated.