Slow start with the head stock.

billmayo · Post by **billmayo** » Thu Dec 20, 2012 10:37 pm

godavid2 wrote:It seems when I tighten the bolt down and tension the belt I get this clicking from the area of the eccentric bushing. I can push the belt in a good 1/4 in. if not more.

I have heard a clicking noise from the eccentric bushing area if the eccentric bushing set screw is too tight when tightening the bolt. I find the wrong set screw end has been used in some eccentric bushings. Shopsmith used idler shafts with the double bearing that had a groove around the center of the bearing for the set screw to fit into. Later idler shaft bearings had no groove where it is easier to overtighten the set screw and get the clicking noise. I have been using a 1" body washer under the screw that prevents the idler shaft from coming out of the headstock so if the set screw does become loose, nothing will change or cause a problem. I set the idler shaft bearing and eccentric bushing againest the 1" body washer so no future movement of the idler shaft or eccentric bushing can occur.

Just do not over tighten the bolt as either of the headstock casing ears that the bolt passes through can be broken.

skou · Post by **skou** » Thu Dec 20, 2012 11:23 pm

I'm surprised this.

Start cap on the motor? That is the FIRST thing I'd check.

David, is this a sudden, new thing, or has it been getting worse gradually?

If it is a new thing, I'd look at the start capacitor.

steve

beeg · Post by **beeg** » Fri Dec 21, 2012 12:01 am

skou wrote:I'm surprised this.

Start cap on the motor? That is the FIRST thing I'd check.

steve

In reality it's the last thing ya want to check. It's like one in a HUNDRED that wood be bad.

godavid2 · Post by **godavid2** » Fri Dec 21, 2012 10:31 am

I'm trying to understand exactly which screw is the eccentric bushing set screw. I have two screw on the outside of the eccentric bushing. A small one and a larger one. The manual does not label which screw is the set screw. thanks for all you help guys. I also agree the slow start up is not the motor capacitor. That it was loose belts causing the slow start up. But when tensioning the poly v belt the eccentric bushing started making a clicking sounds when the motor was almost stopped. I hope, I'm making sense. thanks again for your help.

JPG · Post by **JPG** » Fri Dec 21, 2012 12:23 pm

The motor will 'click' as it slows down(the internal start switch mechanism)(one click). A click can be heard on startup as well, but it competes with the motor running noise.

The idler bearing set screw is in the side of the eccentric. It should have a cone(pointy) shaped end. That point goes into a groove on the outside of the bearing near it's center. Excessive tightening of that screw can place undue stress on the bearing, so snugging it up is all you should do. If the bearing does not have the groove, a non-pointed set screw is appropriate.

A 'set screw' usually(not always in the distant past) does not have a 'head'.

The sole purpose of the setscrew/groove is to prevent the bearing from creeping in/out of the headstock bore. Nope, eccentric bore!

The eccentric clamping screw has both a allen socketed head and a split lockwasher and a nut(older ones have a square nut). That screw should also not be tightened by gorilla paws as doing so can break off the ear(s) that the screw is squeezing.

"A" headstocks did not have another screw(and flat washer) that prevents the eccentric from slipping out of the headfstock bore, but instead used two clips that hung from the clamping screw and a fingers on both ends prevented the eccentric from creeping in the bore.

A recent change to the eccentric added another screw that prevents the eccentric from sliding into the bore, and the bearing from sliding out of the eccentric. It was changed to accommodate the newer two bearing idler shaft that has no need for the 'set screw'. That screw has a HEX(MALE) head with a washer 'built in'. The proper name for that type screw head escapes me at the moment.

The eccentric was also changed then to include an 'open' bottom. That allows the clamping screw to squeeze the eccentric on to the bearings as well as the the eccentric.

nuhobby · Post by **nuhobby** » Fri Dec 21, 2012 12:26 pm

JPG also has a great pictorial on these parts:

http://www.shopsmith.net/forums/showthr ... ic+bushing

JPG · Post by **JPG** » Sun Dec 23, 2012 3:21 pm

The slow start headstock has been referred to as A since another thread was started in an attempt to understand both 'issues'.

This one 'clicks' when the belt tension is increased. The source of that click comes and goes with poly-v belt tension changes. Why it comes/goes is the mystery. A start switch click would not likely com/go with belt tension changes unless perhaps the tension changes the deceleration rate or some other dynamic.

To check for control sheave 'slop', the motor belt needs to be removed from the idler puller. Then one can determine the amount of motion between the control sheave and the idler sheave(the two halves of the idler shaft pulley). While holding the idler shaft, rotate the control sheave and determine the amount of rotation possible with no idler shaft movement. It is possible the vanes are hitting with higher poly-v belt tension on shut off. If the control sheave is worn(either the bore or the keyway or more likely both) it can 'wobble' enough so the vanes will interfere. I had one so badly worn that it could 'jump' a vane - not good!!!! Yes is was 'noisey'(clickety clack...).