Pin Block help

Hi all

Been quite some time since I was on here - sorry....I've missed you all!

Got a 1892 Bechstein 7-footer (an old Model III, I think).

2 questions.....does anyone know how the pin block is fixed to the frame? It wasn't stuck to the plate - only screwed - it doesn't sit on a 'ledge' at either side of the keybed, like some grands......I'm assuming it has wooden dowels into the stretcher and then glued??

Next problem....I measured the thickness of the block at 47mm (at it's thickest point) - can't find a piano supply house that will supply material for a block this thick......the best I have found is a thickness of 41mm...can I just order the block at 41mm...I mean, will this be close enough?.....I know the fitting of the pin block has to be extremely accurate, but I have a feeling that even the pin block that's in the piano at present might not even be the original (the piano shows other signs of a restoration previously done)

Many thanks guys

Mark

P.S. I have contacted Bechstein, and they are unable (or unwilling) to help me with such things as this.

Bechstein lost a lot of their records during the war.

The pinblock may have wooden dowels into the stretcher, or it may part of the structure. Sometimes it is necessary to take the block out by other means. There are saws such as this one (chosen merely as an example, not an endorsement), which can cut the block loose.

You may want to start with the 41 mm material, and then build up to the open face with additional wood. You do not want the bottoms of the pins sticking through.

How many pin blocks have you done? Blocks in those old Bechsteins are much more difficult to replace than newer instruments. The blocks were built into the sides of the case. A person really needs experience to tackle one of those. Bolduc has a video on this kind of job.

Piano manufacturers focus on building and selling new pianos, they really are not interested in hand holding rebuilders.

Bechstein buried their pin blocks in the rim.

I have done a couple recently and had to make up part of the pin block myself.
There is a tongue and groove fit to the stretcher. Underneath the rim where the block is buried, it is only screwed down.

I have a couple of pictures I can post tomorrow when I am back in the shop.

I would be concerned about the plate. They tend to crack just forward of the block in the strut.

I'll post a picture of that as well tomorrow.

Or, ... use shorter pins.
These blocks can be a royal pain in the aspirations of new rebuilders if it's the open faced kind.

Hi BDB

Many thanks for your input. I have already started to remove the block with a saw. I don't think my problem with a thinner block was really my concern - I would NEVER have the pins poking out of the bottom......my concern was merely with stability of the piano if I used a thinner pin block.?

SUPPLY....I have only done about 3 blocks before - all on American pianos! - and all under the watchful eye of Don Stevenson (UWO).....this is the 1st I will have done without him!!! (hence, the aprehension!!)

LARRY - tongue and groove hypothesis would now make some sense to me! I don't know for sure, though.

Greetings,
Odds are that the pinblock is mortised blindly into the sides of the case. If so, and you don't want to cut large pieces of the case away to get it out, you will need to very carefully clean the mortises after you take the block out, after you index the original to the plate and stretcher, (it takes a couple of index holes). Then, the oversize block is fitted to the plate, cut the ends off closely enough so that you can rotate the block into the case and the plate will be in the correct position when there is approx, 3 mm gap at the ends of the block inside of the mortises. This means that your new block will be approx. 7 mm shorter than the original,but there is enough ledge to support it, especially with modern resin glues.
Not a lot of room for error, and you will probably need to radius the distal edge of the bass end and the proximal corner at the treble end so that it will "rotate" clockwise into the case mortises. Insert the bass end first and see what kind of clearances you need to get it all the way in.
Get a block and have a spacer glued on the bottom. you will want to have the full dimension.
Also, be wary, older Bechstein plates just love to crack if they are flexed.
Regards,

These blocks are screwed in originally and the screws buried by the case.

Enough material has to be removed if you are to reach the screws to remove them.

One can always leave a little of the old block at either end and "ship lap" the new to the old.

I've done the ship-lap too Larry and it works well, although Ed's method sounds good also. I think these weak plate struts crack because technicians drive the tuning pins deeper and the added counter-bearing behind the agraffes bends the strut beyond elastic limit.

Stick with the 1/0 tuning pins because that is what they used in my experience and it will tune better. Use a vertical-grain, laminated hard-rock maple pin-block for best results and if the thickest blank is not thick enough, just glue on an appropriate sized bottom layer of highest grade plywood to bring the overall thickness back to original. Use the longest pin that reaches just to the bottom of the maple block.

I suspect the grain of the cast iron was too fine. There are comments when reading old texts that the finer grain gave better detail but was not as string. The Bechstein plates I have seen seems to have a finer grain look to the casting. At least to my eye.

The open face pin block means .. no webbing to help support the plate structure against the rotational force generated by the tuning pins and strings.

It is easy enough to say, remove minimal wood from the case. By the time you have enough room to remove the screws, you can drive a battleship in.

I do really like #1 pins. It is primarily what I use unless directed otherwise by the client.

The original pins would have been even smaller: 6.75 mm (.265") was the German industry standard for decades if not a century.

Yep. 265 was the size in ‘79 Blüthner mod 6 which allowed number two pins to be used in restring.

However, I did find numerous bass tuning pins to be slightly bent.

Hi all

Thanks so much for taking the time to help me out here. It's been so long since I did any of these larger-scale rstorations that some of the details are a little sketchy in my head!

Mark

P.S. I remember the blocks I have done before - drilling them BEFORE fitting them under the plate. But I'm thinking that it may be better to fit the block first, in this instance, and drill with the plate on???

Greetings,
I, like Larry, use the 1/0 pins. The idea came from Chris Robinson, who had to replace a number of soundboards with defective wood,(and he did this as his own warranty). He said that he also went ahead and tore out all those new blocks because he simply couldn't send his work out with 3/0 pins. From that point on, he started all blocks out with 1/0 pins so that any problem could be remedied by going to the normal 2/0.
The .004" difference,( I think), makes a very small difference in surface area, and leaves a lot of room in the webbing.
Last month I took the pins out of a 1965 Steinway M and found numerous bent pins. These were 2/0 and I wonder if the pins were bent in the driving or what. Concerned about oblong holes, I reamed this block with my own invention and installed 3/0 pins. It tunes wonderfully.
Regards

I visited a rebuilder in Berlin a couple of years ago and was pretty surprised to see how they handle Bechstein pinblocks. Read more here.

Your own invention? Tell us more...

A while back, when I knew that I was going to move my shop, I decided to wholesale a Bechstein C. Of course, it had a collapsed pin block. Over the years that I had it in my shop, I had dreaded the thought of the pin block job.

I definitely would look into the Berlin method, if the situation arises again. Why not do that with Steinways, as well and save half the labor hours!

Greetings,
I use a K bit, (.281"). With a Dremel tool, I grind down and polish the first inch of the bit so that there is no cutting edges to remove wood until the bit is aligned with the original axis. This takes about .010" off the diameter. I then do the same at the other end of the bit, leaving me about two inches of cutting edges in the middle. This allows the drill to self-pilot itself in the block so that it is going quite straight when the cutting edges enter the hole and to remain straight as it goes through. I chuck it up in a 3/8" drill and with the trigger locked I drop it straight into the holes. I place a scrap of iron an inch below the block to stop the reamer so that the drill doesn't hit the plate. The reamer is smaller than the pins, but manages to just clean the inside of the holes.

My primary reason for this is to remove the smaller diameter at the bottom of the pinblock where the old pins stopped, and to remove any out of roundness in the hole caused by bent pins. An entire block, when reamed, yields perhaps 1/2 cup of shavings, so there is very little wood removed. However, the holes are all rendered the same dimension. Also, upon measuring numerous pins coming out of the older pianos, I find that there can be up to .003" variability, which the reaming removes.

I suppose modern pins are more consistent than those of 30-50 years ago, and after reaming, I ended up with a restrung piano with torque between 110 and 120 in/lbs. On an older Steinway block, this has proven to be a stable torque,( some of these pianos are tuned 6 or 7 times a year, some of them every week). I don't do this without taking out the plate first and examining the block for structural stability and lack of cracks. The technique works quite well, and I would suggest anyone that want to try this invest the $ 3.50 for a bit and try it out on a discarded block, first.
Hope that helps.

That's great, thanks. Very smart.

Nice Ed!

Yes, Thank you!

That self-aligning feature makes a tremendous difference.