Lee Stofer wrote:You may be onto something here. Due to the differing requirements for lubrication and fit, I think it is probably easier to make rotors with acceptable compression than it is to make really good pistons that would have the same level of compression.
I believe that Bloke also hit upon an important factor, as I doubt that any appreciable amount of fitting of valves is done in the manufacture of new King and Conn tubas. The valves can be made relatively quiet with metal valve guides, but the manufacturer is not willing to spend the time to fit the metal guides that tightly and precisely, as that would cost them more per unit, and take more time away from their manufacture of smaller brass instruments which are more profitable for them to produce.
Al Cass was made for trumpets, not tubas. To make King tuba valves really fast and quiet, I lightly lap the pistons with a very fine lapping compound to make them really fit, do a precision alignment with cork and felt washers, replace the valve guides with nylon guides, and sometimes chuck the bottom caps in the lathe and cut the bottom channel out larger to accept Yamaha valve springs. And, I use Hetman #2 valve oil on them, unless they are loose-enough to benefit from Hetman #3 Classic valve oil. This is a non-toxic synthetic, formulated to reduce friction and wear in your tuba valves and keep the horn cleaner.
As part of the purchase experience, string players seem to expect to take their instrument to the repair shop and have it shop-adjusted (and maybe repaired, if bought used) before they start using it daily. Maybe we should not expect a tuba to be ready-to-play right out of the box. But then, maybe we should expect the seller to perform this service as part of the purchase process.
When I bought my PT-6P in 2000 the valves were undependable and, when cleaning and oiling didn't help enough, I assumed they simply needed more spring tension. I therefore stretched the springs a bit until the valves came up quickly and regularly. I noticed that my finger technique was not very good, but figured that this was yet another effect of age. My hand got sore quickly.
During this past orchestral season, I had a terrible time with the Tarentella movement of Walton's Facade Suite when we did a series of performances with the Alberta Ballet. In practicing this lick all week, my hand felt as though it was falling off.
Shortly after this, a couple of the repairmen who frequent this page suggested that my spring stretching strategy was a poor one and that there were several things a good technician could do to improve valve performance. This had not really occurred to me, but as soon as my season was over, I took my horn to my friend Steve Maubach in Calgary, with a plea to make it possible to use weaker springs with my valves. Using some of the same tricks described by Lee Stofer, light lapping, chemical cleaning, alignment, etc, Steve was able to make a dramatic improvement in the action of the valves while lightening the action. It's hard to believe the difference in the ease of playing the horn. I can now play a D-flat scale more than twice without having to stop to rest and shake my hand.
Anyway, I'm delighted both with Steve's careful work and with the discussion on this board that pointed out what I should have already known. Thanks to you all.
Michael Eastep
However, A LOT can be done in an hour at the manufacturing level... a heck of a lot more than can be done in an hour AFTER the horn is fully assembled and finished. Heck, I doubt if the complete assembly time is much more than 8-10 labor hours.
