Some information about Venco wheels.

Drive Wheels

Two images showing a normal drive wheel (top pic) and a badly damaged one.(bottom photo) At the moment a new drive wheel will set you back around $250 plus installation if you choose not to do it yourself. It’s quite easy to do by the way. The main reason I see this sort of damage is because of missing grommets. You should never use a wheel that has missing grommets because it causes misalignment of the aluminum cone on the end of the motor shaft and it can dig into the rubber causing unrepairable damage. The drive wheels last between about 15 -30 years depending on usage and how the wheel is stored. I have seen some old models from the 80’s where the dive wheel is still usable but usually by this stage they start falling apart. The first sign of deterioration is small vertical cracks around the circumference of the wheel. If got to soon enough they can be reconditioned

A Thing or Two About Motors

The motors used in Venco wheels up until recent times are Australian made and of very good quality. Betts motors are some of the best motors made worldwide. Nothing lasts forever though and there are a few things that can go wrong with your motor. These motors are what is called split phase with centrifugal switch. Basically the wiring inside the motor is split into a light gauge starter windings and a standard run winding.when the power is turned on the starter winding kicks in and this controls the direction of the motor clockwise or counter clockwise depending on setup. After a couple of seconds a centrifugal switch comes into play and cuts the start winding and switches over to the main winding. Because of dust, clay, insects and other crap that can get into your motor, it can cause the centrifugal switch to stick , either in the off position or on position. If it sticks in the on position the starter windings will quickly burn out causing a lot of smelly white smoke and a dead motor. Bad news , a new motor is needed, it’s not worth the cost of having them rewound.

Not so bad if it sticks in the off position. This causes the wheel to start very slowly and may turn in either direction. If it is doing this the motor should be taken out and serviced as it can quickly change at any stage and get stuck in the on position and that magic white smoke escapes killing your motor. A motor rewind shop can do this for you and generally entails blowing out dust and crap and cleaning and lubricating the centrifugal switch. Another thing that can go wrong with a motor is bearings. If the motor is noisy when turned on but is not engaged with the drive wheel then your bearings need replacement. My local rewind guy charges about $100 to clean motor and change bearings. I keep a few reconditioned second hand motors in stock for repairs.

Dealing with Wheel Noises

Washer Kits and Sleeve Bearings

Grinding and weird sounds coming from wheelhead. Try and turn your wheelhead with the motor turned off. It should rotate easily and have very little vertical play. Try pulling the wheelhead up, it should not move more than a couple of millimeters. If it is hard to turn or makes a scraping/grinding sound then some maintenance is required. To remove the wheelhead you need to tip the wheel over and remove drive wheel. Always support the motor when flipping the wheel so as not to cause damage to the drivewheel. If the end of the cone on the motor hits the drivewheel with force it can put a ding in it.

Undo the nut that hold the drivewheel to the shaft and wriggle it up until it comes off. When you turn the wheel back over the wheelhead should come straight out. Check around the top of the bearings and under wheelhead for any bits off stuff like old cutoff wire that may be stuck there. Clean off any lumps of caked on clay that might be causing a noise. Now check that all the ‘o’ rings, metal and fibre washers are in good condition. Refer to the above diagram for correct placement. These parts can be obtained from many suppliers such as Keanes or Walkers. Clean out old stiff grease and apply lots of new waterproof grease to all parts and re-assemble. When you flip the wheel over to replace the drivewheel you will need to put a block of wood or similar under the wheelhead to support it and prevent from slipping down. Check that the lower set of washers are in place and tighten the nut on the drivewheel. It is good to have a small amount of play, a couple of millimeters, between the end of the bearing housing and drivewheel so the wheel head is not too tight. The wheelhead should now turn freely with the motor off.

Brass sleeve bearings used in venco wheels prior to the introduction of the Mark II wheel . They are very long lasting, I have only ever had to replace one set of these over the years of repairing wheels

Motor Mount and Fine Tuning

Sometimes problems may arise with loud grinding noise when the foot pedal is pushed and the motor cone engages with the drive wheel. The most common reason is missing grommets and the repairs needed was outlined previously. Another less common cause can me mis-alignment of the two fine adjustment mechanisms on the motor frame.

Position in the Wheel of Fine Tuning Bolt

First I will deal with the set bolt at the rear of the motor. I spoke to Geoff Hill a few years back and he explained the reason for this bolt. He said it is factory preset and under normal circumstances , should not require any modifications. The bolts controls how and where the cone engages with the drivewheel rubber when it first touches it. If the cone is too far over the point of the cone will hit against the metal part of the drivewheel and produce an awful grinding noise. If it is too far the other way then the tip of the cone will not engage properly with the rubber and you get no slow speeds, or the wheelhead will stop with a small amount of pressure applied. Adjustment is very small amounts, half a turn at a time.

Rubber Boot on Motor Cradle Adjustment

I am not too sure what to call this other than the sticky out metal bit welded onto the motor cradle. Its purpose is to stop the wide end of the cone going past the rubber on the drivewheel. This can cause damage to the rubber on the drivewheel and can also ‘lock’ into position and grind away. It should have a rubber shoe on it as pictured above. In side the shoe can be up to 4 or so small metal washers. These are there to fine tune the exact position that the cone stops at while on full speed. The way of testing is to turn the wheel on its side with the motor turned off. Gently push the pedal down all the way until it stops. Put your hand against where the cone and rubber meet and the sharp bottom edge of the cone should be just below the rubber ring.

The rubber boot is perishable and it is commonly seen missing in wheels that come to me for repairs. You may have noticed the small spring attacked to the sticky out metal bit and i will explain their purpose next.

Springs and Things

There are two springs in venco no3 and 5 wheels. The small one attaches to a small lug on the underside of the drip tray , the other end to the motor cradle. This spring maintains the correct pressure between the drivewheel rubber and cone so you get enough force to throw a decent amount of clay. Too much pressure would cause excess wear to the drivewheel so it’s important to only use springs supplied by venco. These are available from good pottery suppliers.

The large main spring is there to help with the amount of force needed to depress the foot pedal and get the wheel spinning. When in off position of the foot pedal the spring is stretched out in tension. When you press the pedal it helps lift the motor to engage the cone. Without it you would have to press very hard on the pedal to raise the motor and it would get very tiring quickly. The spring is always in tension so over time it looses its springiness and becomes ineffective. If you hold the spring up and give it a little shake and it feels all floppy then it’s time to change it. Generally speaking they are not expensive items and can make your wheel feel like new again.