Shopsmith Forums

dusty wrote:I do not recall whether the eccentric came with that screw or not. I think it did because I do not have that sort of screw in my parts collection.

The washer Dusty, the washer. Your pix has a washer, the others only have the 'hex washer head' screw. i.e. your pix has a screw and a washer.

dusty wrote:Maybe you guys know better than I because of your experience but I see these retainers a bit different than I think is being stated.

In rele's photos (the ones showing the broken screw), it seems clear to me that the washer at 12 o'clock prevents the eccentric from creeping out of the headstock.

Conversely, the screw and washer in the eccentric at 8 o'clock prevents the eccentric from creeping into the headstock.

Placing a larger washer at 12 o'clock will not do that.

My theory is based on a premise that the bearing is not going to move on the shaft and therefore it's position (and the shaft's position) is fixed once the bolt is tightened (securing the position of the eccentric).

Sorry to disagree with you but the washer shown in rele's photos (the ones showing the broken screw) will not prevent the idler shaft bearing from coming out of the eccentric bushing once the belt is tighten with the eccentric bushing. The motor belt pressure will keeps the idler shaft from moving inward. With the solid older eccentric bushing, only the eccentric bushing set screw prevents the idler shaft from moving inside the eccentric bushing. The eccentric bushing bolt only hold the eccentric bushing from moving in the headstock and holds the belt adjustment. I have had to replace dozens of Gilmer & Poly-V belts that was damaged when the eccentric bushing set screw loosen. I find the eccentric bushing set screw is not tight in about 25% of the headstocks I rebuild and the eccentric bolt loose in a few headstocks.

A little history as I understand it on why this area became a problem. The original idler shaft bearing had a center groove machine around it. The eccentric set screw had a point that fitted in this groove. Even if the set screw became loose, the set screw point would prevent the idler shaft from moving inside the eccentric bushing. Later years, the idler shaft bearing no longer had this groove, so the set screw had to tighter to prevent his movement. If the pointed set screw was used on the straight idler shaft bearing, over tighting the set screw would deform the bearing shell resulting in a bearing tick when operating. Many years ago, I first tried used the flat point set screw on the straight idler shaft bearing but found one had loosen in the headstock I was using. I also found a few eccentric bolts had loosen allowing both the eccentric bushing and idler shaft to move out of the headstock. I realized that a larger 1" OD washer would hold both the bearing and the eccentric bushing from moving out of the headstock. This solved any problems I have been seeing and still contain to find in this area.

SO I am a little, well okay, SERIOUSLY confused on how to proceed. I have had the bottom pan off when cleaning it and oiling my Mark V.

The idler shaft, is there a bearing on the back side, the part thayt is inside the motor housing? IS that waht came out?

When I was attempting to put the eccentric back in I was putting it into the place and was hoping then I would be able to work the idler shaft back, however that didn't happen, which is why in the pics it shows the eccentric further in than the idler shaft bearings.

Could I trouble someone to go into detail of what I do, or link me to a place that can show me? You guys have been great. I just wish my friend would have tapped the eccentric whilst in the machine still and not remove it, LOL! O well.

rele wrote:SO I am a little, well okay, SERIOUSLY confused on how to proceed. I have had the bottom pan off when cleaning it and oiling my Mark V.

The idler shaft, is there a bearing on the back side, the part thayt is inside the motor housing? IS that waht came out?

When I was attempting to put the eccentric back in I was putting it into the place and was hoping then I would be able to work the idler shaft back, however that didn't happen, which is why in the pics it shows the eccentric further in than the idler shaft bearings.

Could I trouble someone to go into detail of what I do, or link me to a place that can show me? You guys have been great. I just wish my friend would have tapped the eccentric whilst in the machine still and not remove it, LOL! O well.

Always check the Poly-V/Gilmer belt path or a a noticeable angle between the pulleys. If the belt is not rubbing the headstock casing and making sure the belt tension is OK, then just snug the eccentric bolt and leave good enough alone. I like to be able to depress the belt between 1/16" - 1/8" with my finger.

rele wrote:SO I am a little, well okay, SERIOUSLY confused on how to proceed. I have had the bottom pan off when cleaning it and oiling my Mark V.

The idler shaft, is there a bearing on the back side, the part thayt is inside the motor housing? IS that waht came out?

When I was attempting to put the eccentric back in I was putting it into the place and was hoping then I would be able to work the idler shaft back, however that didn't happen, which is why in the pics it shows the eccentric further in than the idler shaft bearings.

Could I trouble someone to go into detail of what I do, or link me to a place that can show me? You guys have been great. I just wish my friend would have tapped the eccentric whilst in the machine still and not remove it, LOL! O well.

Post #49 this thread step 1. Make sure the poly-v belt is positioned on the pulleys correctly. The belt should be centered on the idler shaft pulley, and two grooves visible at the end of the main shaft pulley facing the quill.

You probably feel like a one armed wallpaper hanger trying to get the belt, pulley, bearing(s), eccentric to mesh correctly!

I am suspicious that the rear bearing may have slid back on the shaft towards the end. Try pulling it all the way off and then you should be able to peer into the eccentric bore and see what is going on up front. The rust needs to be cleaned off the shaft first.

P.S. A has been suggested, removing the motor belt from the motor pulley will slack the belt and it will then not interfere with getting the idler shaft etc in place.

JPG40504 wrote:Post #49 this thread step 1. Make sure the poly-v belt is positioned on the pulleys correctly. The belt should be centered on the idler shaft pulley, and two grooves visible at the end of the main shaft pulley facing the quill.

You probably feel like a one armed wallpaper hanger trying to get the belt, pulley, bearing(s), eccentric to mesh correctly!

I am suspicious that the rear bearing may have slid back on the shaft towards the end. Try pulling it all the way off and then you should be able to peer into the eccentric bore and see what is going on up front. The rust needs to be cleaned off the shaft first.

P.S. A has been suggested, removing the motor belt from the motor pulley will slack the belt and it will then not interfere with getting the idler shaft etc in place.

rele ~ JPG's P.S re-removing the motor belt and pushing it up off the control sheave will allow you to move the idler shaft in to position.

Orv Leu wrote:rele ~ JPG's P.S re-removing the motor belt and pushing it up off the control sheave will allow you to move the idler shaft in to position.

Oh I see it now, and do I need to remove the quill? I think it is called that, in order to do so?

EDIT: also my belt was off center, much like described on the sawthingy video, factory set. Should I keep it that way, I have seen much debate on the accuracy of that since joining...

billmayo wrote:Sorry to disagree with you but the washer shown in rele's photos (the ones showing the broken screw) will not prevent the idler shaft bearing from coming out of the eccentric bushing once the belt is tighten with the eccentric bushing. The motor belt pressure will keeps the idler shaft from moving inward. With the solid older eccentric bushing, only the eccentric bushing set screw prevents the idler shaft from moving inside the eccentric bushing. The eccentric bushing bolt only hold the eccentric bushing from moving in the headstock and holds the belt adjustment. I have had to replace dozens of Gilmer & Poly-V belts that was damaged when the eccentric bushing set screw loosen. I find the eccentric bushing set screw is not tight in about 25% of the headstocks I rebuild and the eccentric bolt loose in a few headstocks.

A little history as I understand it on why this area became a problem. The original idler shaft bearing had a center groove machine around it. The eccentric set screw had a point that fitted in this groove. Even if the set screw became loose, the set screw point would prevent the idler shaft from moving inside the eccentric bushing. Later years, the idler shaft bearing no longer had this groove, so the set screw had to tighter to prevent his movement. If the pointed set screw was used on the straight idler shaft bearing, over tighting the set screw would deform the bearing shell resulting in a bearing tick when operating. Many years ago, I first tried used the flat point set screw on the straight idler shaft bearing but found one had loosen in the headstock I was using. I also found a few eccentric bolts had loosen allowing both the eccentric bushing and idler shaft to move out of the headstock. I realized that a larger 3/4" OD washer would hold both the bearing and the eccentric bushing from moving out of the headstock. This solved any problems I have been seeing and still contain to find in this area.

OKAY, I defer to your extreme experience level BUT THEN please explain what that screw and washer are there for.

BTW I do not believe that the eccentric that I recently installed (the new design) has a set screw.

rele wrote:Oh I see it now, and do I need to remove the quill? I think it is called that, in order to do so?

EDIT: also my belt was off center, much like described on the sawthingy video, factory set. Should I keep it that way, I have seen much debate on the accuracy of that since joining...

The debate(here) was whether it is two or three grooves back from the quill end. No question it is not all the way towards that end. The later machines seem to be 3 not two(that would be you). Perhaps it is the different idler shaft/bearings that determine that. Visual checking after it is all together can zero in on where it needs to be(not rubbing against anything and square to the pulley). The belt can be moved with the eccentric set to slack the belt(not the easiest thing to do, but possible).

The quill does not need to be removed for what you are trying to accomplish today!

dusty wrote:OKAY, I defer to your extreme experience level BUT THEN please explain what that screw and washer are there for.

BTW I do not believe that the eccentric that I recently installed (the new design) has a set screw.

I may not coincide with Bill, but this is how I see it(keep in mind I am assuming the 'new' screw head extends past both the inner bore and the outer surface of the eccentric).

As Bill pointed out, the motor belt will apply pressure against the idler sheave which will prevent the idler shaft from moving into the headstock.

The screw and washer at the top prevents the eccentric from moving out of the headstock.

The new eccentric does not have the set screw that secured the older bearing/idler shaft to the eccentric.

Without that set screw something needed to be added to position/retain the new idler shaft/bearings). The rear bearing is still free to move out of the eccentric, and the eccentric is still free to move into the headstock.

The new screw(not sure if Dusty's washer is OEM) will prevent both movements since its head(and washer?) will hold the bearing in the eccentric, and also hold the eccentric out of the headstock.

I am not totally clear of the shape of the new idler shaft, but I think the bearings are positioned to the shaft by increased shaft diameter at the inside face of both bearings. I assume the rest of the shaft is the same as the older version. The front bearing is held captive between the shaft od step and the idler sheave(maybe a clip instead????)