D Shaft Bearings

[Mike Stalker]

Guys, I,m going through my PBL's and have decided to go with the D shaft because of old style shaft wear at the bearing seat.

Boss ordered bearings through US Bowling. The bearings came and they do not have reusable seals.

Who does? I like to repack my own bearings and these do not have enough grease in them to last very long at all.

I appreciate your imput.
Mike

[Coors]

Re: D Shaft Bearings

just save the seals from your straight bore bearings

[Mike Stalker]

Re: D Shaft Bearings

Coors, I have a miss mash of parts here, but the inner race is a different thickness and the seals do not fit.

[knuckles]

Re: D Shaft Bearings

Whatever you do mike, you'll end up saving yourself time and your back with the D-bore shaft and bearings.

I started changing mine three years ago, as the old shafts started wearing out. Now that I have them all changed over I have not pulled a ball lift out because of premature wear of lower shaft for six months.

You'll be a happer mechanic when you change yours.

larry [img]/content/btubb/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

[Jimmy Jam]

Re: D Shaft Bearings

How does the shaft become damaged? What causes it?

[knuckles]

Re: D Shaft Bearings

JJ
The only thing I have figured out was 5 years ago I took out the old kickers and replaced with the pbl's. Sometime after that I started replacing lower shafts on a monthly bases. When I realized I was replacing the same lower shaft on the same ball lifts after 3 or 4 months of use, I switched to the D-bore shafts.
When I reinstalled the lifts with the D-bore shaft,I made sure every thing else was lined up correct and put in new uprail covers and installed the black amf ball lift belt.

The problems disappeared.

larry

[Coors]

Re: D Shaft Bearings

shaft gets grooved when the ball lift shaft starts spinning faster than the bearing.

a groove starts to form on the shaft, then over a period of weeks, first you hear the grinding, then a little squeeling, then either the belt starts poppin off, one lane will start to slowly make the other pit run, and/or the shaft flat out snaps.

the D-bore basically ensures the bearing is rotating the same speed as the shaft, so no groove ever starts.

like knuckles said, some lower shafts need to be replaced 3X a year without d-bores. usually those pairs are offset

[WHERE IS THE SHOT]

Re: D Shaft Bearings

The only problem with the D shaft and bearings
is if you have narrow kickbacks it's a bi***
to take off your carpet drive belts. I had one
pair of lanes where the nuts were almost rubbing
the kickback.

[Mike Stalker]

Re: D Shaft Bearings

You guys haven't answered my question. Good conversation though.

I have several offset pairs.
These bearings are not pressed on; if they were, shaft wear would be much less prevalent.

Change the retainer design and use snap rings and you can use pressed bearings. (redesign the shaft of course)

also,
If a bearing fails and locks up, good bye shaft.

I am going to a bearing place today. $23 each is too high and I'll let you guys know what I find.
Mike

[8270 pinspotter]

Re: D Shaft Bearings

$23.00? Where are you getting parts from? I know I didn't pay that much for them from AMF. Probably about half that. I don't know off the top of my head, but I'll look and post it later.

[8270king]

Re: D Shaft Bearings

On the space problem:

You need to get the new races for the clutch pulley with the long slot. It prolly gives you 3/16 narrower shaft assy without the old bronze bushing. You must utilize the new spacers from whoever.

The previous tech at our place ordered tons of Vantage shaft kits. Their shafts seem a little soft. When dissambeling them after a year or 2 the shafts have massive wear spots at the bearing race.

I like the bearings with all metal carriages for the roller bearings. The plactic ones do not seem to be as sturdy.

Jerry

[Coors]

Re: D Shaft Bearings

$22.80 from Vantage

[Jimmy Jam]

Re: D Shaft Bearings

Originally posted by Coors:
shaft gets grooved when the ball lift shaft starts spinning faster than the bearing.

a groove starts to form on the shaft, then over a period of weeks, first you hear the grinding, then a little squeeling, then either the belt starts poppin off, one lane will start to slowly make the other pit run, and/or the shaft flat out snaps.

the D-bore basically ensures the bearing is rotating the same speed as the shaft, so no groove ever starts.

like knuckles said, some lower shafts need to be replaced 3X a year without d-bores. usually those pairs are offset

<font size="2" face="Verdana, Helvetica, sans-serif">I rebuild 1 or 2 a year(18 in operation, 3 are D-bore). Last one was July 2001. Usually its because of a bad clutch bearing.

I would give you assembly tips on the old style but it would be a waste of time. Just buy the D-bores.

[Jimmy Jam]

Re: D Shaft Bearings

That sounded bad. If you want to know how to put them together let me know.

[Mike Stalker]

Re: D Shaft Bearings

Once again Motion Technolology (bearing specialty) cannot find this bearing anywhere. Which means order from AMF. I have seen both D-bore bearing seal designs; I just can't remember who had it.

Remember the PBL lower shaft design is a shaft where the bearing slides on. Once the belt tension is applied, pressure is only on one side of the bearing inner race which creates a gap on the other side of the bearing between the inner race and the shaft.

Using the same loose (shaft/bearing) design the
D-bore ensures that the inner race is spinning, which means the shaft will not wear at the bearing seat.

Thanks for the good imput.

Mike