Delta 14" Bandsaw lower bearings.....help needed

Rob Keeble

Member
Messages
12,633
Location
GTA Ontario Canada
Ok so i set about changing my lower bearings.

Unfortunately when the motor side came out these two load springs fell.
uploadfromtaptalk1335399685474.jpg

I did post asking about them without a pic but had no joy on a reply.

So this evening i went back at it with camera and got some pics.

Now Delta show only one on the assembly drawings but the little info i can find on the web has one post somewhere mentioning that some guys have found up to three.
Here is my bearing

uploadfromtaptalk1335399889480.jpg

So my questions to you all is do these two go in like this "back to back"
uploadfromtaptalk1335399979834.jpg

or stacked next to each other. If stacked which way. To my knowledge they meant to press against the outer ring of the bearing.

Then how tight do i make the nut. Because boy i battled to get it looose but you cannot tighten an arrangement like this or you end up with the bearings loaded axially and thats not how they are designed.

Also can i put a spacer between the wheel and the bearing on the shaft on the wheel side so that the wheel is up against the centre ring of the bearing when the nut is tightened down.

On this arrangement . One side is fixed to the shaft then goes into the casting and the other side slides on and gets secured with one nut.

Help please.

Sent from my MB860 using Tapatalk 2
 
Thanks Alan. Thats not my particular bandsaw but it is delta and shows the two spring config. I find it strange that in a machine made in the USA mine is the X5 Delta 14" 28-475X that they use two and did not show them on the drawing. They only show one. Now at least i know how they put them. Funny thing is on another forum i found the guys think they should go back to back. One side springs pushing on the casting edge and the other side pushing on the bearing outer ring.

Another interesting thing is the addition of the washer before the nut. I would have also thought in this case there should be two nuts.

Here is my understanding so far of this whole issue.

The way the lower wheel is mounted is different from the upper wheel.

On the lower wheel the wheel is secured to the shaft with the bearing set to be secured between the shoulder on the shaft and the roller bearing. There is also a key to stop the wheel rotating and make it drive the shaft.
The bearing is a slide fit to the casting.

Now if one were to put the motor side bearing in which is a slide fit over both the shaft and the casting recess and tighten up then a few things happen. If two much tightening is done the wheel will not even move given the force is being applied to the bearings.

If one backed off you still have a problem in that when the bearing heats up the whole thing would seize for the same reason.

So to prevent this the shaft is machined such that when the whole assembly is put together there is a gap between the casting and the motor side bearing.

Well we dont want the wheel rocking from side to side when it starts up or this will transfer to the blade and who knows where the blade will end up running.

So these finger springs are inserted and act as a tensioner to put load on one side of the bearing and displace the shaft to the one side thereby allowing the shaft to stay in one place and cater for the movement that is going to occur when the bearings heat up and expand.

Of course these are small amounts we are talking about but they are significant in the whole assembly working smoothly.

I guess placed one on top of the other these springs must work the same as if one shoved two coil springs into a barrel. You gotta have more tension to compress two than one.

The thing to remember is this bandsaw has a larger than most motor so I guess the need for greater spring tension is neccessary but then why did it not make it to the manual. ????

The other thing is a washer on the bearing side would make more sense to me than the nut on its own.

I guess my concern is whether the machine was assembled properly. This is not part of the assembly the owner does when they get it in a box. Its factory done.


The gap if one leaves them out for a moment and rocks the assembly sideways is significant.


Given what i found in the upper wheel, my confidence that this machine was ever put together properly is completely gone. So much for the premium i paid to support "Made in the USA".

I have had a belief since day one that all was not right with this machine. Bit by bit at different times after reading others experiences i have found out more and more and learnt more and more about setting them up.

With a little tenacity and determination, like a Stanley plane, i think they can be turned into great bandsaws.


When i bought it i was totally ignorant not a member of a forum and relied on the "Taunton Tool guide" and "Made in USA" as a means for determining quality. Well i am a little wiser today.


I also bought into the concept of a fully enclosed metal base. Yeah right. The lid or top of this base is plate. Secured to the base by screws. Were it 1/4 inch thick i would say great. But it aint.

Another guy i found on the web put in a 3/4 piece of particle board to stiffen it up. He said it made a world of difference. I plan on doing the exact same. I have intuitively thought this from the very beginning. But figured "dang Rob you aint a mechanical engineer" surely "the Delta guys knew what they were doing" yeah right. The value engineering guys may have. :)

I still have an issue of how tight to make the nut? Dont you guys think there should be two nuts?

On my vintage scroll saw they have two nuts in a similar config except the bearings used there are Timken tappered bearings so they need to be held in place but without being tightened up too much. In this case there is no pre load spring.


Its really well worth getting familiar with your machines in this way.


Anyone have any idea on a practicle method of determining how tight to make the tension nut.?


My thinking right now is to place it all in and only hand tighten it to take up the slack so there is no side to side play. Leaving the springs almost uncompressed. This will alow for them to compress when the whole assembly heats up. :dunno:
 
Well i have gone straight to Delta on this.

For those Delta owners with questions here is where you can access Delta directly and hopefully get some answers.

http://www.deltamachinery.com/service-support/faq

You can sign up and post questions and they will answer in 8 - 10 days. We shall see what they say about this.


BTW i tried to post at the OWM site and well my first post was considered SPAM and if anyone thinks our COC is out of hand go read theirs. Boy i could not believe it.
 
Ok well the good news i Delta got back to me. So that help line for Delta works.

They answered every question.
The finger springs go back to back and they said if there was two when i took them out to put two in when i put them back.

They also said no washer needed before the nut on the drive side on the lower bearing. I disagree with this but will follow their rules.

They also said no to two nuts.

Then the thing that has suprised me most is they said tighten lower nut to 30 to 40 ft pounds of torque. This i will check with a buddy of mine that used to service woodworking machines and i will see what it feels like with a real torque gauge. It could be correct because that aint much torque but now that i know which way the springs go will be able to put it all back together and see how that tension works out.

I am going to take a lot of pics and make up a tutorial on this bearing change over. Its my view that all these cast iron 14 inch saws are the same and that there is way to little factual info on the whole thing on the web.

Will try my best to put something together that should be generic, would be great if someone is intrested in changing out their bearings on a similar saw would then check what i have done and see how it pans out as a comparison.

I find it hard to believe a Grizzly or Jet or Powermatic are that different when they all based on the exact same configuration of cast frame.

Will report back when the job is done. Looking forward to seeing how the saw runs after what i consider to be the final tune up. :) Should never say that word. ;)
 
I'm late to the fray, but I was wondering why you're replacing the bearings? Just a general upgrade or was there a problem you're trying to fix?
 
One thing I have learned in my old age is if I use a Carter stabilizer on blades 1\4 and narrower upper and lower guides are not used or needed. The key to great performance is a 'sharp' blade.
 
So i just wanted to finish up on this thread.

I replaced my bearings and oh boy what a new machine. Shame on Delta for claiming at the time to supply a US made machine and put real junkie bearings in it. For what i paid for this machine i could have bought two top of the line Grizzly units in the same category. So much for supporting home made manufacture. :(

Ok apart from fixing up the bearings I had also discovered that the more vibration you take out of the mounting with these small saws the better the whole operation.

Even though mine came with a steel cabinet, the cabinet is a bolt together one and with it on teh floor there is nothing securing the base of the metal casing. Then the top plane that the huge casting rests on is not exactly a thick plate they try to make up for this with many bolts to the cabinet sides.

Sooooo

I cut two pieces of 3/4 baltic birch ply and put one under the top steel plate secured new bolts and tied the cabinet up to it. At the same time while i had the wheels off doing the bearings i drilled out the mounting holes in the casting and put in larger diameter bolts. So when all pulled up its now nice and solid.

To round this off the last piece of BB ply i put on the bottom and with the help of some left over angle iron from an old bed and some lee valley casters and rockler caster i built a mobile base around the bottom.

Now my bandsaw is pimped.

I saw this kind of mod in a post by a guy with a blog and i can only echo what he said. It really paid off to get the vibration out of the whole machine.

From the base to aligning the pulleys and the belt to fixing the bearings. Its now smooth and finally a pleasure to use.

Its has not cost much to do these fixes but the effort has well been worth it. I highly recommend it to anyone who wants more out of their 14 inch bandsaw.

Bandsaw mobile base.jpgBandsaw base.jpg
 
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