Chasers on viennese pianos

Sorry to discuss anything to do with pianos of the forte type but I am not sure if the yahoo list is still going. My question is concerning chasers those slotted wood things glued to the top of the key for the balance pin to run in. Most viennese pianos after 1800 had them as well as all modern pianos. Originally I had the idea that they provided a more precise fit for the balance pin to reduce any tendancy for the keys to rock sideways causing the attached hammers to misstrike particularly with unachorda down. I have used beech chasers on all my walters but never on harpsichords.My concern is that the need to drill a 6mm clearance hole beneath the chaser weakens the key particularly with the sugar pine i am using. I am now thinking of going back to key mortises as made with the punch/broach as provided with the hubbard kits, tests show that the key is much stronger under breaking tests. In any case Streichers and Brodmanns created the balance mortise and front guide mortise with a tiny circular saw (woodruffe cutter) so as in both cases we have a slot directly made in the key lever.
What do people think.

My own approach with harpsichords where the fit is sloppy is to glue two wooden pieces about 2-3 mm thick, one on each side of the balance pin. This assumes the pins protrude above the mortise 2 - 3 mm, which they usually do. I install them with a single tiny drop of glue beyond each corner of the mortise, to make them easy to remove and to avoid glue getting in the mortise.

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