Allen Drawknob disassembly and engraving

[fjonker]

Hello all,

We are converting an Allen 903 console for use with Hauptwerk and would like to move/re-engrave some of the drawknobs for our standard sample set.

Any tips on properly diassembliing the drawknob? A few of the engravable white endcaps unscrewed easily from the stem, but many are very firmly screwed in place and it seems that the white and black stems are also rotate independently of the central metal shaft.

Thanks in advance for any tips... we plan to post details of the work in the future to help others.

Fernand

[jbird604]

I would think that all the drawknobs on a given Allen would be identical in construction. If you found that some of the heads screwed off, then surely the rest of them will unscrew as well. If they are screwed on very tightly it might take some force to break them loose. You must be very careful, of course, as they are probably irreplaceable. I do know that Allen used different drawknob designs over the years, but surely all the knobs on your organ are the same.

[fjonker]

Hi John,

Thanks for the response. Yes all the drawknobs are the same on the console... the trouble is that the drawknob end is very tightly attached to the stem and the visible parts of the stem appear to rotate around a central metal shaft.. I was hoping somebody would have experience taking them apart and could share a trick or a good method for doinig so.

Here is a pic of the drawknobs in case it's helpful... note that the top right one is already removed.

[John Kinkennon]

Hi Fernand,

I know we discussed this before, but for the forum members I will repeat that I've seen a lot of cracked Allen drawknob heads and have had them literally crumble in my hand when trying to unscrew them. Hopefully someone has suggestions. I'd be inclined to try heating one just a little with a heat gun to see if that helped. The entire shaft can be removed by loosening a set screw at the rear of the assembly. However, any rough treatment of the stems such as gripping them with pliers will make a bit of grinding necessary to get them reinstalled.

Have you spoken with Cheryl at Hesco?
http://www.hescoincorporated.com/engraving.shtml
Their catalog didn't show these heads but I'll bet they have them or can reproduce them.

[toodles]

I've seen several cracked drawknob heads, too, on older Allen models.

I have not done this, so it is just a possibility: remove the stem as John Kinkennon discussed, and then remove the shank as I believe there is no attachment means to the head--it's just held in place by the pressure of the head screwed onto the shaft. Then put the shaft/head in the freezer to make the shaft contract a little to loosen the head. Or maybe just put the shaft but not the head in ice water for a while.

You might also try penetrating oil, but hydrocarbons (like the penetrating oil) can sometimes cause plastics to deteriorate.

[jbird604]

I know that Allen has used more than one type of drawknob. A few years ago a church bought a lovely Renaissance, then a new organist came on board who was certain that the division marked "Positiv" on the organ was in fact a "Choir." And he wanted the Festival Trumpet to be called the "Pontifical Trumpet," along with a few other name changes. He was so adamant about it, the church had the Allen dealer, who I did some work for at the time, order some new drawknobs, coupler tabs, and nameplates to make the changes he wanted.

So I was sent to the church to change all these out. The drawknobs were just a tad smaller than the ones I was familiar with on the ADC organs I used to sell, and shaped a little differently. But they screwed off rather easily, came off in one piece. And the new ones went on easily too. The cap didn't appear to be a separate piece from the body of the knob.

With the ADC models (and presumably MOS organs too), we could change out just the white cap at the end, which we did a few times to add a knob for MIDI in place of blank one. I don't remember having any trouble doing that. But I can't recall if it had to be unscrewed or if it just popped off. I have some old blank ones at the shop that I can look at next time I'm over there. Might jog my memory.

[John Kinkennon]

Fernand and I are rebuilding almost identical Allen 903 models. Mine came from a father and son who had previously attempted a MIDI conversion. For some reason all the felts had been removed from the drawknobs (please don't) and I had to punch 60+ of my own using 3/8" felt and an arbor press. I did learn just what a pain it is to remove that many drawknob stems and in the process noticed that trying to unscrew a stuck drawknob head can exert a lot of torque on the little driver board at the rear of the assembly. These are the older two piece heads and I wonder if it might be best to remove the shaft and head so that the shaft can be gripped with pliers close to the head where a little marking of the shaft won't hinder the reassembly. Just a thought as I know there were some heads so tight that I gave up on trying to remove them lest I do some expensive damage.

[myorgan]

I know this is reviving an old thread, but a recommendation from me for unscrewing the heads as John mentioned above is to use a lock grip wrench with a cloth around the shank near the head. By using the cloth, the pressure is still exerted on the stem, but the serration of the wrench claws wouldn't mark the stem.

Michael

[fjonker]

I know that Allen has used more than one type of drawknob. A few years ago a church bought a lovely Renaissance, then a new organist came on board who was certain that the division marked "Positiv" on the organ was in fact a "Choir." And he wanted the Festival Trumpet to be called the "Pontifical Trumpet," along with a few other name changes. He was so adamant about it, the church had the Allen dealer, who I did some work for at the time, order some new drawknobs, coupler tabs, and nameplates to make the changes he wanted.

... Wow! That's an interesting experience!

Thanks for all the ideas and info folks! I will attempt to remove a few stems and see how it goes.

I have also contacted Hesco... I'll see what they say.

[fjonker]

Oh... and some of the drawknob heads do appear to have fine cracking in them... so jbird604 if yours are compatible we might be interested in buying your spares.

And if anyone knows someone who may benefit from some of the old guts (card reader, cards, boards, transformers... ) let me know.

[myorgan]

And if anyone knows someone who may benefit from some of the old guts (card reader, cards, boards, transformers... ) let me know.

Let me recommend the Organ Forum Classifieds. I'm sure you'll find a taker if you keep the classified up long enough. Thanks for not trashing the extra parts!

Michael