Slide rule cursor misaligned, how did happen?

[butforwales]

I picked up a K&E N9081-3 to give myself a tutorial. The inaccuracy in results lead me to a closer look. I realize the top scale involving DF is misaligned from the rest. The item looks free from alterations. How could it become misaligned?
https://ibb.co/1LBdwvS

[Geoff Quickfall]

Really? Can’t tell from the text if you are stating the obvious ;-) the frame is cracked.

To align the slide you position the cursor over the right all left indices. Then loosen the screws and adjust the glass in the frame so that it is parallel to the left or right indices.

I have actually made new cursor glass using 1 diamond glass and HF past.

Cheers, Geoff

[butforwales]

Hi Geoff,
Thank you for the reply! For me as a casual user, the item is actually in good shape, there is no blunt damages and the fittings are tight. It came with a worn leather case with the original owners name tag, address and phone number.
The problem is that when the '1' of C and D align, the 'π' of CF and DF don't. I can try to loose the two flat screws and hope there is enough play to realign them. But I feel like someone didn't know what they were doing. Wasn't that supposed to be precise instrument? And 1947 American quality?

[Garth Wilson]

(09-26-2021 02:49 AM)Geoff Quickfall Wrote:  To align the slide you position the cursor over the right all left indices. Then loosen the screws and adjust the glass in the frame so that it is parallel to the left or right indices.

The C and D scales are aligned with each other, but the CF and DF scales are not aligned with each other. You'll need to loosen the screws that brace the two long stationary pieces of wood, and align those pieces. When they're perfect, then see if the cursor is still needing alignment, using the two outer scales and seeing if, for example, the .5 on the LL02 (top) scale lines up with the 2 on the LL2 (bottom) scale, and adjusting the cursor if they don't.

[Benjer]

Supposing you get your slide rule aligned as described in Garth's post, I noticed that both the top and bottom cursor end pieces are each cracked. Some models of K&E slides rules have self-destructive cursor end pieces which eventually crumble to bits, (K&E rotting cursor syndrome, or KERCS), and there's nothing that can be done to stop it. I've tried gluing the pieces back together and they've crumbled apart into smaller pieces.

Other cursors from K&E don't suffer from this, so replacements are sometimes obtainable, usually by taking the pieces from another unwanted slide rule.

[Ren]

(09-26-2021 08:13 AM)Benjer Wrote:  Supposing you get your slide rule aligned as described in Garth's post, I noticed that both the top and bottom cursor end pieces are each cracked. Some models of K&E slides rules have self-destructive cursor end pieces which eventually crumble to bits, (K&E rotting cursor syndrome, or KERCS), and there's nothing that can be done to stop it. I've tried gluing the pieces back together and they've crumbled apart into smaller pieces.

Other cursors from K&E don't suffer from this, so replacements are sometimes obtainable, usually by taking the pieces from another unwanted slide rule.

Sounds like time to fire up the 3D printer...