Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Regulating Dimensions for Mehlin Grand

All,
Does anyone know where I can get the regulating dimensions for a 6' 4" Mehlin grand? Key height, hammer blow, checking distance, and so on. It was built in 1902. Unfortunately, my 1991 edition of the Piano Action Handbook does not mention Mehlin.

Also would like to know if there is any way to get information about the original hammers. Someone put heavy hammers on it about 12 years ago, so it has a heavy touch. About 72 grams at the low end. I can calculate the weight of the new hammers, but I would prefer to get information about the originals if possible. I have completely gone through the action, rebushed quite a bit. And have been playing it off and on for 12 years since then. So I know nothing is inappropriately tight in the action. I know the guy that replaced the hammers right before I bought it intentionally put 16 pound hammers in it because he likes a heavy touch. It's the hammers' weight, not friction in the action.
Thank you,
Jerry Viviano

Mehlin pianos are often full of surprises, I get the impression Mr. Mehlin was quite an inventor and experimented a lot. He was in good company (Jonas Chickering and others come to mind)

That being said, I would start with standard regulation specs and see what the pianos tells you. If that is above your level of expertise, call in a professional technician.

If you are SURE that the hammer weight is the only problem with the touch, then "all" you have to do is to reduce hammer weight. There are two ways: replace with lighter hammers, or trim/taper the existing hammers. It is possible to take off close to 2 g on some sets, resulting in 10 g less downweight.

Again, if you need to ask how to do this, you are better off calling in a pro.

good luck - it sounds like an interesting instrument!

Jerry,
The 16 pound designation means nothing unless you know how many sets of hammers were made from the 16 pound slab of hammer felt. It is silly of the suppliers to talk about hammer sets using this terminology.
Just for your own information and satisfaction you should have an idea if the action has any geometry problems. Some can be solved easily and you may be able to avoid hammer issues as described above.

Gene,
Sorry it took me so long to get back to you. I forgot to set the email notification flag on this post, and then forgot about it. They say the memory goes first. How true!

Everything in the action appears to be original except for the hammer heads and a few of the shanks. I had regulated it before. Even after regulation the touch weight was quite heavy. So unless there has been some major shrinkage, it's not obvious to me that there could be much opportunity for the geometry to be different than as it was originally. And supposedly the Mehlin grand has traditionally been seen as a quality piece, meaning that originally it should have been right. Correct me if you see otherwise. I'm still somewhat new to piano technician work. Still learning some things.

Lots of things point the hammer selection as being the culprit here.
1) The technician who I bought it from said he intentionally put heavy hammers on it to increase the touch weight because that's the way he liked oianos to be when he played. He claimed he was rebuilding it for his own use when he found a piano called a Blasius which he liked better.
2) There is very little wiggle room between hammers in the base end. That is, unless everything is adjusted exactly, exactly right, hammers will rub on each other, moreso than on other pianos.
3) I've compared hammer #1 to those shown in the Renner catalog. It is significantly larger than any of those offered by Renner.

So it seems like I really need to get the hammers reduced on the piano. It's a bit of a shame, as the hammers that are currently on it are almost like new.

Thanks for your suggestion,

Jerry, once upon a time, I bought a Mehlin 9' with a touchweight of 85grams, in other words a Schwarzeneger piano. The scenario was the same as yours. New hammers, but way too big and heavy. This is pretty typical of many hammer installations I have found in older pianos. It now plays in a respectable 55-45 gram range. All that was required was narrowing the hammers and shaping the tails. I have done this procedure in all of my rebuilds to date. "New" does not mean finished. It is really the starting point and you need to work from there. Ideally when I am tearing down the action I remove the hammers, and weigh them on a gram scale. The new hammers need to replicate that weight allowing for previous hammer shaping for example.(This assumes that you have already evaluated touchweight and found it to be within spec.) Digital gram scales are available through Harbor Freight as an example for around $18 if memory serves.

Jerry
There are different ideas about hammer mass and how it is used. I typically will favor a slightly heavy hammer especially in the lower 3rd of the piano because I always get better tone. That said, this can create touchweight problems and they need to be dealt with. Just hanging heavy hammers is not a logical approach. The action geometry must be analized and hammer mass incorporated with the equation.
Sacraficing tone for touchweight is a balancing act.
I don't know why someone would add heavy hammers to get heavy touchweight - removing one key lead would be a better choice in my opinion.
Many times there are problems with hammer spacing in the bass and usually this is caused by trying to match the (hammer angle) with that of the strings - or get it close anyway. This is not necessary and I bore mine at around 6 degrees which eliminates spacing issues even for large wide hammers in most cases.
Hammer size is not always equiv to hammer mass. This is why I mention "how many sets of hammers come from a 16 lb set?" You really need to put the hammer on a gram scale. Hammer density and mass is the equiv or proportional.

John,
When you say narrowning of the hammers, do you mean tapering the sides down as Spurlock recommends, taking felt off the front and back of the hammer below the shoulders, or both? I've been wondering for years if it is OK to take felt off the front and back, essentially narrowing them front to back. I've never seen it mentioned anywhere.
Thanks for the Harbor Freight suggestion on the gram scale. I was wondering where to get one.

Gene,
I will look at the mechanical advantage and verify once again that it is the standard 5:1, as I have no other Mehlin-specific specs to go by. I have checked that about 10 years ago and seem to recall that it was right on. I will verify that the jacks are aligned properly to the knuckles. Assuming that the geometry was correct when it came from the factory, and that it still has the correct original whippens, hammer flanges, and hammer shanks, what else could change in the geometry to make it wrong?

I know blow distance, let-off, key-drop, check distance, key dip, aftertouch, and all such standard regulation adjustment come into play, but I don't think that's what you're refering to here as being under the 'geometry' heading. I've checked that all those things are correct, at least as far as I can tell. Please fill me in on what you're refering to.
Thanks to both of you,

I had a piano with similar probelms recently. By using a jig on a table saw, I was able to narrow and taper the hammers, removing almost 2 g off the hammers in the bass and less in the treble of course. It is not a good idea to file hammer felt off the shoulders in an effort to reduce weight.

Jerry, yes taper the sides and remove wood below the shank. There is also some wood to be removed in the area of "checking" I tend to curve the tail some as well. Jurgen's idea about the table saw is a good one. I tend to use a stationary sander using a 6" disc. A coarse (80 grit) will remove it relatively quickly. It is easier to taper the hammers prior to installation as the shank gets in the way to some degree while sanding the hammer post installation.

Tapering below the shank will hardly reduce weight. I am talking aout making the whole hammer narrower. Taper it right form the crown. The crown can usually be taken down to 9.5 mm in width, tapering down to 6 mm at the tail. This is only if there are no tri-chords in the bass. For tri-chord areas, 10 mm width should be wide enough to strike all strings properly.

This can be done quite precisely on a table saw with a decent jig. John is right, the best time to taper hammers is before hanging them. But they can be tapered on the shanks - the jig may need some modification for this.
Very often, using a disc/band sander will cause ugly bleeding of color from the underfelt and molding into the white hammer felt.

And sometimes, an accidental manicure if your fingers get too close

Yes, the reddish color can stem from your fingertip...

I don't know if there is a jig to do this job safely and with repetetive precision on a sander. Those are few more reasons why the table saw jig is a good idea.

You can do all sorts of repetitive sanding quite accurately with a Shopsmith, since the disk is on a quill. I will post photos of my keytop sanding jig sometime.

There are various ways to do this. I do the sides freehand with a 1-inch wide Delta belt sander. It's helpful to have them glued to the shank already, because you have something to hold onto. This is a good way to do it for me because I am often trying to hit specific strikeweights, and can control how much weight I take off very easily. On one hammer I might need to take off a little, and on another it might be alot.

To shape the tails for checking I use the Spurlock jig. It saves time if I'm doing a specific strikeweight curve from the start, because I can pick up the hammer, trim the shank, shape the tail, and trim the sides at one time.

Juergen is right that sometimes it causes the underfelt color to bleed onto the white. The ones done with a tablesaw do look nicer.

Hey BDB. I am interested in the Shopsmith setup. I just picked up an old 10er unit. It's old, but a nice machine. I have various stand-alone machines, but wanted to try one of these, and it was very reasonable. I have various ideas of what to do with it, but any guidance you can give would be great.

A 10er is kind of tough to adapt, because parts are hard to find for it. I have a very old Mark 5, about what they call the 500 now. When the upgrades to the newer models became available, I got a couple of extra table assemblies from people who upgraded. I removed the tabletops from them and made jigs. One now has a narrow table positioned 1/2 the thickness of a hammer below the trunnion pivot axis, which I use for boring hammers. I line the hammer up with the axis, and then I can change the angle without changing anything else in the setup. The other is my key sanding jig, version 2. Version 1 was just a board with a right angle piece on it to hold the key horizontal against the Shopsmith table, and away from the center of the disk so the sandpaper actually moves. Version 2 has dust collection which is better than what I had for version 1, more adjustments, and an area to use a rubber disk cleaning bar without changing the setup.

To taper hammer tails, all you need is a piece of plywood with straight edges. Screw a metal plate at one corner so that it sticks out about 3/16" to hold the hammers at the same position at the corner of the plywood. Clamp the plywood to the edge of the table so that the tail of the hammer butts into the plate, and so it holds the tail in the proper position so that the sanding disk can be pushed into it. Hold the head of the hammer against the plywood, use the quill to sand it on one side, then flip it over to sand the other side.

The nice things about all these jigs is that you can hold the part safely with one hand and operate the quill with the other. You do not have to fumble with clamps for each of 88 hammers or keys. The jobs just take a few minutes.

That makes sense. Seems like a fine method.

I'll figure it out as I go. I knew I was getting an older unit. I kind of like it though, in a nostalgic way. I already have all of the tools I need for piano work, but I'm sure I'll find uses for this. It seems like the biggest liability is that to change speeds you have to move the belts on the pulleys, vs. turning a dial.

Has anyone ever tried using a band saw to taper the sides of hammers? I have a nice Delta bandsaw with 93 inch blades. It has a guide slot similar to a table saw. I could make a jig to hold the hammers. The table tilts on it, which may come in handy as well with the angles involved. The teeth on the blades are generally much smaller than the teeth on a table saw, which would seem appropriate for the felt and generally small dimensions of a hammer. I would expect it to not cause color bleeding, similar to a table saw.

Haven't tried it. Bandsaws are great, but I have my doubts. The blades tend to bend with sideways pressure. It wouldn't be my first choice, but could probably be done if you were determined enough. Do you have some spare hammers that are expendable? Experiment before you try it on any hammers you don't want to lose.

Roy
Nope. No spare hammers. But I can see if I can pick some up at the next PTG meeting I go to. It's usually held at a piano refurbishing shop.

I've had pretty good luck with controlling things on my bandsaw. I hardly ever use my radial arm saw, which may be even better. I need to play around with some spare hammers, as you suggested.
Thanks,
Jerry

There have also been some articles in the Journal about using a Wagner planer on a drill press and getting nice, clean results. Haven't tried it, but hoping to soon.