Shopsmith Forums

dusty wrote:Replacing either of the 7x22x10 backup bearings with a 7x22x7 set does only one thing that I can see. It provides a groove between the two bearings in which the blade can ride. If I am wrong on this point, some one please set me straight.

My question, however is "Exactly what does that groove do that is not accomplished by the cool blocks"?

It 'guides' the back of the blade rather than the sides.

It reduces the need for the side guides.

Advantage? Methinks that is subject to 'opinion'.

In LDH's original design, the spacers retain the sleeve between the screw and the id of the bearing.

Getting the groove positioned can be a challenge. OEM screw can be used, but ends up being a mite short.

Bill Mayo puts a thin shim between the bearings to increase the groove width.

If you are telling me that this is just another way of accomplishing exactly the same thing then I do not believe it is worth the effort. That opinion is further supported by my discovery that I would have to file off material on both the upper and lower backup bearing brackets in order to align the bearings with the blade.

The lower bracket is adjustable but does not go quite as far as needed on my two machines. Close but no cigar. The upper bracket needs even more filed off to reach the objective.

I think I am talking myself into either sticking with the original configuration or giving the Carter setup a try.

dusty wrote:For the backup bearings, if you eliminate the bushings and use 627ZZ bearings, you can accomplish the same task as depicted in the referenced drawings by LDH.

I am a bit confused on the purpose of the .0625" shim though. Installing that will move the bearing set to the left and I need to move that bearing set to the right to make the bearings align with the blade.

The .125" shim, I believe, is there just to consume space on the shoulder of the 1/4"x 20 bolt.

That shim is not used on my installation either. Not sure why it is there unless there are some saws with a different guide post/bracket.

John, did you have to file on the bracket to make the bearings align so well with the blade. Without filing, my bearings would be about the thickness of the blade too far to the left.

dusty wrote:If you are telling me that this is just another way of accomplishing exactly the same thing then I do not believe it is worth the effort. That opinion is further supported by my discovery that I would have to file off material on both the upper and lower backup bearing brackets in order to align the bearings with the blade.

The lower bracket is adjustable but does not go quite as far as needed on my two machines. Close but no cigar. The upper bracket needs even more filed off to reach the objective.

I think I am talking myself into either sticking with the original configuration or giving the Carter setup a try.

I wonder if not all guide posts or bearing brackets are the same. If you only have a single backup bearing the side to side positioning of the bearing can be off 10 or 15 thou and not affect anything. I did that mod years ago and did not have to use the small shim and the bearings lined up perfectly with no filing. it's been running that way with no problems for 7 years.

I agree with JPG on support of the back of the blade but I don't agree it eliminates the need for side guides. With a single bearing the back of the blade can slide back and forth across the face of the bearing resulting in the blade twisting slightly. With the grove the blade is held much truer but if you eliminate the side guides the front of the blade can still twist.

In fact that is exactly the principle of the Carter Stabilizer (not the Carter side roller guides). The stabilizer is used without side guides (upper or lower)and only on blades 1/4" wide or less.

From the Carter web site...

"The unique patented Stabilizer® from Carter is very different from any traditional guide in that it is not designed to hold the blade with immovable support on three sides. Instead, its grooved bearing wheel firmly prevents the blade from moving backwards or shifting left or right while still permitting the front of the blade to twist slightly side to side. This allows the user to make tight radius complex curves that no traditional guide system can achieve."

So yes you want three sided support. The single backup bearing only gives you front to back support and the double bearing gives you front to back and side to side support to the back of the blade.

As for cool blocks, they are OK. I used them for years before Carter came out with the SS roller guides. Cool blocks are soft and wear which requires adjustment and re-dressing the ends. The Carter guides are pretty much set and forget. I set the rollers to just barely touch the blade. With the saw running the rollers turn but I can touch them and they stop.

The combination of the double bearing backup and the Carter guides makes for a very stable setup. In my opinion blade stability is key to getting good cuts on a band saw. ANYTHING you can do to increase blade stability is worth it. The other component is of course good quality sharp blades.

I had to refer back to my thread on modifications to the ci bandsaw so I could refresh my memory about the bearing replacement I did.

http://www.shopsmith.com/ss_forum/viewt ... 626#p96626

"The lower set was way off on my saw. Again the adjust is just left or right but I could not move things far enough to get it aligned. At this point I could have filed the parts or... make changes by changing the bushings around. I went with the bushing change and got to the point of having the alignment within the range of the other parts. Again here adjusted the bearing so the blade was not deflected by the settings."

So no filing on mine.

I have carter guides on my other bandsaw and I do love them. It was the single most improvement I've done on the saw. It was expensive, somewhere in the $150 range even when I did them many years ago.

I was thinking I might do the carter guides on the shopsmith but the bearing change I did seems to work very well and was a lot cheaper then the carter set. I did get the single bearing carter stabilizer for when that is needed but it doesn't get a lot of use.

I really wish I had a noisy bandsaw to look at and play with. When looking at mine I do wonder if the noise people hear is due to alignment issues.

To get the saw cutting right takes effort, getting the alignment right is an art form. I would look to the bearings being at some minor angle off of the perpendicular that they need to be to the blade. Also making sure the blade is not deflected in anyway by the positioning of the bearings and that the bearing locations are correct.

Anyway just wanted to say that I'm pretty happy with my shopsmith bandsaw with the bearing upgrade I have and don't plan to spend the extra money on a set of carter guides.

Just for reference the whole post is located at:

http://www.shopsmith.com/ss_forum/maint ... t8361.html

Ed

John, absolutely no argument here.
The SS is my only B/S and I wish I would have gone the Carter route well before I did.

When I did the double bearing upgrade I used the .0625 shim as directed but had to a couple of much thinner shims to move the bearings out far enought that the blade centered between the two bearings. I had the file the lower guide bracket quite a bit to gain clearance for the two bearings.

Jack

Gene Howe wrote:John, absolutely no argument here.
The SS is my only B/S and I wish I would have gone the Carter route well before I did.

Most band saws have roller guides. Why? Because that is the best way to support the blade. The blade needs to be supported properly to make a good cut.

I love the SS band saw. There is absolutely nothing wrong with it. It works perfectly (Carter guides and double backup bearings) just like the big boy band saws. It was my only band saw for a long time. The only reason I bought the Powermatic 14" saw is to resaw wider stock (12") for my wife's scroll saw work. I keep a 3/4" blade on the Powermatic for re-sawing and use the SS for pretty much every thing else.

I used to re-wsaw on the SS with a 5/8" Timberwolf blade and it was perfect.

claimdude wrote:When I did the double bearing upgrade I used the .0625 shim as directed but had to a couple of much thinner shims to move the bearings out far enought that the blade centered between the two bearings. I had the file the lower guide bracket quite a bit to gain clearance for the two bearings.

Jack

This is just weird.

It seems to me that the bearing bracket is not that precise. Don't know why since if it was manufactured according to the print they should all be the same within the tolerance. There is always a tolerance on the print. A few thou depending on the precision required.

You and Dust say things are way out and mine is not. As I said, parts are made to a print with tolerances and can't be that far out unless the print changed.