First a few very important points:
1. Please remember that the FX Control is not suitable for all locos. Please check the lists for the latest information.
2. Home fitting is only possible for those locos where the standard 1/4" Chuffer is used and where there is sufficient room in the chimney for the loco to breathe. If your loco already uses the smaller, 7/32" chuffer, there will almost certainly not be room for the FX Control. Where the space is already limited for the 1/4" Chuffer, Nigel Garrett will fit an exchange 7/32" Chuffer and FX Control for you.
3. Home fitting is really only only appropriate for folk with model engineering skills and access to a good quality lathe. Although the Summerlands Chuffer is precision engineered, the top of the chuffer resonator simply has a cap pressed in and silver soldered - resulting in a slight swelling of the body and a less than perfectly flat top. This needs to be trued up on the lathe and then the Control must be precision fitted to give a very close, but smooth, free turning fit.
4. The fit must allow free turning with no hard spots. This will ensure that on a threaded fitting e.g. Accucraft, there will be no strain on the thread.
5. If you are using it on one of the tube fitting SCGP Chuffers, you will have to ensure this is a tight fit on the exhaust. Either put a slight bend in the copper exhaust so that it grabs, or make a slight groove round the tube by gently using wire cutters.
Please read the instructions below and if you are in any doubt about your ability to do this, please just send your chuffer to Nigel Garrett at DP Supplies and he will do the job for you.
Before starting, please remember that the resonator walls are only 1/64" thick and have been anealed in the manufacturing process. While the Chuffer is robust enough for a lifetime of use, it would be easily damaged in a lathe.
Fitting Instructions (only if you are satisfied that you can do this safely)
1. You will need to start by making a collet to protect the Chuffer in the lathe chuck. Take a piece of K&S 9/32" OD tube about 30mm long. Clean up the ends and then cut it longitudinally with a razor saw. This will grip and protect the chuffer body in the three jaw chuck.
2. With the Chuffer in the collet, mount it so that just about 5mm is protruding. Using a sharp cutting tool, correctly adjusted so as not to leave a nib, square off the end. It is not good enough to leave a nib and then take this off with a power sander!
3. When the end is true, ease the chuffer out to about 10mm and true up the diameter at the end using a number of very fine cuts. The aim is to bring it back to the same diameter as the body of the chuffer and no less. Try the cap every few passes to see if it will fit. You are only removing a tiny amount and at this stage you are aiming for a tight fit.
4. Now ease the chuffer out to expose 25mm of the resonator and using either a smooth file or 600 grade abrasive paper, gently dress the outer surface of the chuffer until the Chuffer will just slide on. Then change to 1200 grade and continue until the fit is perfect and the Control turns smoothly but will not drop off. Make sure you take great care and oberve all appropriate safety precautions when doing this.
5. When you are satisfied with the fit, it is time to drill the Chuffer cap. You need to drill a 2.2mm diameter hole through the cap with the centre offset 1.5mm from the centre. If you plan to fit a number of these, then I recommend constructing a simple jig to ensure the correct placement.
Where you are drilling an SCRH1 Chuffer, it is best to have the hole either at the front or back for ease of location when the cap is in position.
Do not use either of the holes in the FX Control as a guide as this will result in you drilling down through the wall of the Chuffer (see photo right!). If you plan to hold it in the soft jaws of a vice to do this, then use the collet you have made. Mark the point carefully and do not use an automatic centre punch as most are too severe for this.
If the chuffer has a screwdriver slot, this will be fine, but if it is at all off centre, use the larger side for the hole.
See photo below: left to right - SCAC2 with FX Control, SCRH1-S, fitted with the smaller 7/32" Chuffer, SCAC1 showing hole in resonator and the FX Control
The FX Control is designed to be precision fitted to the Chuffer
The end swells slightly during manufacture
And the Chuffer body needs reducing slightly to give a smooth fit
Do not use the FX Control as a drill guide - this is what happens!