Table Saw Rebuild: Disassembly and Inspection
Before diving into the project, it’s good to review a couple of helpful reminders:
It’s really easy to lose parts
- There aren’t a lot of different parts but keeping them in one place is important.
- I used magnetic parts tray but a jar or small cup will work too.
It’s easy to forget how things go together
- I reassemble as much as I can as soon as I can. Even if I know it will need to come apart again this will help me to keep track of the parts and gives me practice on how they go back together.
- I take photos or video showing how things go back together whenever I think something will give me trouble later on.
- I might get unexpectedly interrupted during disassembly. The interruption might take me away from the project for hours, days, or even weeks. So, leaving things as assembled as possible and keeping photos of stuff might just save the project.
Disassembly
- I removed the blade, blade guard, and the throat plate.
- I removed the fence, guide rails, mounting hardware, and table extensions.
- After that, I removed the belt. This is easily done by lifting up the motor and taking the belt off of the pulleys.
- Then I removed the motor. On some saws the motor is bolted to the frame. For this saw the motor can be removed by pressing in two spring loaded pins at the hinge point.
- Finally, I removed the switch. For the most part, removing the switch allows me to take away the motor and all of its wiring.
At this point I’m ready to unbolt the saw from the legs and place saw upside down on the floor. Normally it would be prudent to put down some wood or a piece of carpet to protect the table surface from damage. But, in this case it just doesn’t matter. I don’t think that the concrete is going to cause any harm.
I continued by removing the hand wheels.
Both the blade tilt and blade elevation shafts have these roll pins that need to be removed. A pin punch is needed to push the pins out of their holes. I support the shaft with a block of wood before trying to tap out the pins. If I don’t do this the shaft will flex with every tap on the punch and the pin won’t move.
Then I removed the screw that holds the blade tilt angle pointer.
Finally, the sheet metal shroud is ready to be removed. There are four bolts that hold the shroud to the table.
Somehow, two of the bolt holes in the shroud were damaged on this saw. The shroud will need to be repaired before reassembly.
Here is the other damaged bolt hole. Once the bolts are removed the shroud can be taken off with the shafts passing through their respective holes.
Doesn’t look like much without the shroud! I’ve put the hand wheels back on temporarily so that I can keep track of the parts.
The blade carriage will come free from the trunnions when the trunnion bolts are removed.
I took this photo so that I could remember how the blade tilt shaft went back together.
The shaft is held in place with collars which are held in place with set screws. Here’s a close-up photo showing how the set screw slipped and gouged the surface of the shaft. Gouges like this will need to be smoothed over with a file before the shaft can be pulled through the bushing. Attempting to pull it through without filing the gouges smooth will cause damage to the inside of the bushing.
The shaft was also bent. It must be straightened before it can be pulled through the bushing.
I marked the inside of the bend with a felt tip pen so that I could remember which way the bend went. Then I placed the shaft in a milling vise with three aluminum blocks. These will provide the pressure I need to straighten out the shaft. I use aluminum because it is soft and won’t cause dents in the shaft. A plain old bench vise can be used to do this just as well. I carefully bend it back a little at a time, checking periodically to make sure that I don’t over do it.
With the shaft removed, it becomes obvious that the bushing wasn’t drilled on center. This is done on purpose to allow for adjustment. We’ll see this again when the saw is reassembled.
I wanted to polish the surface of the shaft in the lathe to remove rust, scratches, and dings. But, it would be dangerous turn such a thin rod supported on only one end. So, I center drill the end of the shaft, allowing it to be supported by the tail stock center.
Here’s the setup I used to polish the shaft. There is no reason to remove the worm gear so I left it on.
To prevent gouges in the future, I filed flats in the shaft where the setscrews go. I will reassemble the collars onto the shaft with thread locker so that it will not loosen.
Inspection
Before taking any measurements, I cleaned and scraped all the important surfaces.
I put the front trunnion on one inch gauge blocks on the surface plate to measure it’s height at top-dead-center.
Then I compared that measurement to the top-dead-center of the rear trunnion on the same gauge blocks. The trunnions were within 0.0023″ of each other. This is excellent. I pretty much expect them to match to within 0.005″.
Then I put the table into the machining center to measure the height of each boss. The difference between the lowest point on the lowest boss to the highest point on the highest boss was 0.0329″. This is not so excellent. In the next installment I will be machining the table. The first step will be to make sure that all of the bosses are at the same height. They will be used to fixture the table when I machine the top. If they are not all at the same level then the table will not come out flat.
The last thing I wanted to do was check arbor/flange runout and the condition of the bearings. Unfortunately, the arbor is threaded all the way up to the flange so I wasn’t able to obtain an accurate measurement. However, I did measure the flange runout using the setup shown above. This is a 0.0001″/div test indicator and I have it mounted with a small magnetic base. Anything under 0.001″ of runout is acceptable and I measured a total indicated reading of 0.0006″ - which is very good.
Pushing and pulling on the arbor didn’t reveal any measurable axial play. As I mentioned in the article on table saw diagnostics, bearing play should be less than 0.001″. It can affect the accuracy and reliability of measurements needed to align the blade. Vibration from axial play will produce a poor quality cut which will need further work (jointing) before glue-up. If the play is more than 0.005″ then the bearings are worn out and need to be replaced.
Finally, I rotate the arbor by hand to see how it feels. If it rotates with a rough and gritty feel then the bearings are damaged and need to be replaced. The bearings on this saw rotate freely and smoothly and appear to be in pretty good condition.
Comments and questions are most welcome. Let me know if I missed something!
Ed Bennett
ejb@tablesawalignment.com
August 9th, 2008 at 10:08 am
Wonderful layout and documentation of the rebuild process, Ed! Very interesting…looking forward to the completed project success!
Thanks,
Ted
August 9th, 2008 at 12:09 pm
Ed,
I find your progress inspiring and someday I myself would like to take on such a project. My question is, while you have the saw disassembled, have you given it any thought to modifing it with a Riving Knife setup? The reason I ask is because I have been toying with the idea of a mod for a “new” Delta Hybrid that I recently purchased and am totally disappointed with the blade guard and splitter system. Your thoughts and advise would be welcomed.
Thomas
August 9th, 2008 at 12:41 pm
Hi Ted,
Thanks for the feedback! Let me know if there is anything in particular that you want to see.
Ed
August 9th, 2008 at 12:46 pm
Hi Thomas,
Thanks! I know what you mean about the stock guard and splitter. I wasn’t thinking about a riving knife so I’m glad you brought it up. I’ll look into it. There are a lot of aftermarket options, are there any in particular that you are interested in?
Ed
August 14th, 2008 at 11:05 pm
Very interesting take here. I am curious how you arrived at
the appropriate tolerances for the different components.
Was it just knowing what should be done via experience
or was there something else at play?
Also, please keep in mind that many, like me, are not
sure of terms - like “bosses”. You might take time to
identify what they are when you introduce them.
Also, wouldn’t one do as well by replacing vs repairing
or milling parts? I don’t have a metal mill and certainly
no experience in working metal.
I have an older Delta jointer that I’m think of
doing the same thing you’re doing here, so the
general things - videos, pictures, layouts, capturing nuts, screws,
etc are VERY helpful.
Looking forward to the next round.
August 15th, 2008 at 8:45 am
Hi Mike,
My take on the tolerances is based on a couple of things. First, it’s familiarity with the machining processes. While it’s possible to do better, it’s generally accepted that tolerances for production milling are about +/-0.005″ (sigma of about .0016″).
The arbor/flange runout and bearing play are based on experience, knowing what is possible and necessary for good quality results.
Second, I’m considering the effect that these tolerances will have on the alignment of the assembled saw. I’ve done experiments to determine how much misalignment will cause a noticable change in the quality of the cut when using a high quality blade. Even with magnification, misalignment below 0.005″ has no noticable effect.
The “bosses” are the small pillars sticking out of the casting where the trunnions and the shroud are bolted. The height of the bosses that are used to mount the shroud aren’t critical. But, the relative height of the bosses that mount the trunnions will affect the trunnion alignment. If they aren’t machined at the same height, then the trunnions will need to be shimmed to obtain proper trunnion alignment.
On this saw, both the lowest and the highest bosses were for mounting the trunnions. It’s hard to say how they got this way. It could have been due to poor workmanship (improper fixturing of the table during machining). Or, it could be that the table was not properly stress relieved prior to machining and had done some “relaxing” afterward. In either case, 0.0329″ is awful when you’re shooting for 0.005″.
Thanks,
Ed Bennett
ejb@tablesawalignment.com
August 27th, 2008 at 10:30 pm
Hey Ed, I recently aquired my Dad’s old Craftsman Contractor style table saw. I pretty much did what you have done here, but the primary mission was just to clean it UP! It produces a moaning sound that has me worried about impending motor failure. I contacted sears.com and downloaded the drawings and parts list. They tell me the bearings are “lifetime” bearings and cannot be repaired or lubricated, and that the motor is no longer manufactured. Upon disassembly I found the casting date of April 1968. I was 11 when Dad and I built the thing and we spent many “quality time” hours with it until I got the late teen wandering syndrome.The saw works fairly well but tune up is a bear. I noticed a set of trunion adjustment screws in the Woodcraft catalog. Will these really help. Woodcraft puts a really hard sell on them. Are there any sources where I might find someone to check the bearings? I may be intrested in your loaner program at a later date. If the bearing problem is insurmountable, I may just have to get a new one, that would be sad as it is still a good machine and it has alot of nostalgia in the dustbin. I think I still have the dis-assembled pictures if you’re interested. Great site. I have a lot to learn here.
August 27th, 2008 at 11:33 pm
Hi Tom,
Congratulations of the success of your rebuild project! I’ve been exchanging email with another member who has rebuilt his saw with great success. I’m planning on featuring member rebuilds in separate articles in this category so if you have photos and a write-up, please send them!
My Dad has a really old Craftsman contractor style saw too. Does yours have a rack and pinion fence adjustment? Several years ago he had trouble with his motor too. So, I sent him a brand new TEFC motor (so that sawdust was no longer a problem). He bolted it up and it works great. Motor mounts have been standardized for many years. It could be that your particular motor is unique, but it would really surprise me. Take it to a local motor shop and I bet they can match you up with a replacement. If you’re lucky, you’ll save a few bucks on a rebuilt motor.
Also, it could be that your motor uses some strange and unique bearings, but I doubt it. I’d bet that they are a standard sized sealed bearings that can be pressed out of the motor housings and new ones pressed right in their place. Any motor shop should be able to change out bearings or even re-wind the coils without any difficulty.
Let me know if you need more help.
Thanks,
Ed Bennett
ejb@tablesawalignment.com
August 29th, 2008 at 2:25 pm
Hi Tom,
It looks like I missed your question about the trunnion adjustment screws. These are the “Pals” that I mentioned in the blade alignment article. I have heard nothing but good reports about this accessory but I haven’t tried it myself. Hopefully I will get a chance to do so when I reassemble this saw.
Ed
ejb@tablesawalignment.com
August 29th, 2008 at 9:56 pm
Mr. Bennett,
I just wanted you to know that this article gave me the courage to try to repair my new Delta hybrid which arrived out of the box with .07″ toe out. After nearly a month at the Service Center, which fixed nothing, I got the saw back a day before your article posted. I followed your steps, disassembled the saw, loosened the trunnion brackets, pulled the trunnion into alignment and put the thing back together. I settled for .002″.
You’re the man. Thanks for all the great advice and the clarity of your writing.
August 29th, 2008 at 10:03 pm
Hi Ted,
You’re welcome! It’s a shame that you had to go through all of that for a brand new machine but I’m glad that I could help you figure it out.
Ed
ejb@tablesawalignment.com
January 25th, 2009 at 6:02 pm
Ed,
I only recently found this site. I have just bought an old Rockwell contractor saw. I need to disassemble, clean, lubricate, tune the saw exactly as you are doing. I won’t have access to all the equipment you are using, however, I can make do. I already know I need to replace the saw’s arbor bearings as they are making a growling sound. I have tried to detect any play/movement in the arbor (none detected) by just removing the belt and wiggling in place. The sound is pretty loud. I definitely hope you show the arbor bearing replacement in your rebuild. I think I can do it, however, I have found very little instruction on the process.
Great site, great service to saw owners everywhere. I anxiously await your projects continuation.
Thanks again,
Stan
January 25th, 2009 at 11:04 pm
Hi Stan,
Welcome to the group!
Time has been a very precious commodity these days so I haven’t had a chance to get back to the rebuild project. But, I followed my own advice and have kept all the parts together, assembled as much as possible, and (as you can see here) I have pictures of how everything goes back together!
When time permits I will do an article on how to replace the arbor bearings. It’s not too difficult and I think it would be helpful to many.
Let me know if you have any other questions.
Thanks,
Ed
February 27th, 2009 at 6:27 pm
Hi Ed,
Like Stan, I recently purchased a used Craftsman Contractors saw that makes a loud growling sound at start up and has what feels like about 0.001″ play in the arbor bearing. I will be looking for your pics and narrative on replacing arbor bearings
Johnny
February 27th, 2009 at 11:53 pm
Hi Johnny,
I hear you! I would like to get back to the rebuild project myself but economic factors are keeping me pretty darn busy right now. Perhaps things will start getting better soon.
Thanks,
Ed
May 26th, 2009 at 12:08 pm
Hi Ed,
Just bought a second hand Delta 34-444 as my first table saw and started the cleaning & rebuilding process. Thanks for putting together such an informative and carefully thought out site, it’s been invaluable in the process.
Like Stan & johnny, I’ve found that the arbor bearing sounds like it needs replacing (flange side by the sounds of it) so if you ever get the time to run through a bearing replacement just know there’s another fellow who would appreciate it greatly.
Thanks again for such a great resource.
- Stuart
May 26th, 2009 at 11:43 pm
Hi Stuart,
Congrats on the acquisition!
Thanks for the feedback. So many have expressed their thanks for the information. I really appreciate knowing that my work has value to others. I wish I had more time to devote to the blog. I’m pretty much doing everything I can just to survive right now. When I get a chance I will show how the bearings are changed out.
Ed
May 13th, 2010 at 4:04 pm
Ed,
Like many others above, I have purcased a used Delta contractor’s saw. I believe that the arbor bearings and motor are OK, but I would like to flatten the bosses on the underside of the table so that I can minimize trunnnion mis-alignment. How difficult/expensive would this be for a local machine shop? I live in Greensboro, NC so there are certainly a few machine shops out there.
I am looking forward to the continuation of your rebuild.
Mike
Tha
May 13th, 2010 at 10:29 pm
Hi Mike,
You’ll just have to call a few up to find out. There are a lot of hungry machine shops out there right now so I would bet that you get come pretty competitive quotes.
Thanks,
Ed
August 6th, 2010 at 8:13 pm
Ed,
I own a Sears contractor’s table saw. I’ve been remodeling my kitchen and was ripping numerous pieces of 1″ x 2″ ash lumber into 3/8″ x 2″ planks so I could run a bead on them for insets into the cabinet doors. I was obviously putting quite a stress on the saw. Eventually, the saw developed a horrid screeching noise and I couldn’t use it anymore. At first I thought it was the belt screeching - similar to a loose belt on a vehicle, but now I firmly believe the noise is coming directly from the arbor. The motor runs normally. The tension on the belt is fine and the belt is not slipping. The screeching actually sounds like metal on metal. I want to replace the arbor. I’m getting flack from my husband. He’s convinced I can’t do it and I need to call a repairman. We live in a rural area and I don’t want to pay a repairman to drive out that far, they always charge extra. I need advice from an outsider. If it can be done by a common person, male or female, I need to do it myself to save money. Is it possible? Oh, I bought the saw in 2002, so it’s not that old. I don’t have the model number right this moment, but I can get it if need be. Thanks!
August 18th, 2010 at 6:46 pm
Hi Wilma,
It’s hard to say exactly what is wrong with your saw without being there to actually inspect it. It could be a bad bearing in the arbor assembly. If you have trouble inspecting the various parts and narrowing down the source of the problem (basic deductive reasoning and process of elimination), then I would say that you will be challenged to effect the repair.
Take a look at the procedure I wrote up for changing arbor bearings. It should give you a good idea of all that’s involved. Your saw will probably be different on some minor points but the basic steps will be the same. Do you follow the whole process? Does anything seem particularly difficult? Is there any part of the process that you can’t see yourself doing?
Sometimes I ask people “Are you a good cook?” They look at me like I’m crazy. But, cooking is just a matter of following directions and rules to obtain an outcome. People who like to make up their own rules (before understanding the principles) tend to be bad cooks. People who don’t pay attention to details tend to be bad cooks. People who can’t follow directions tend to be bad cooks. Do you get discouraged, quit half way through the dish, make excuses for why it didn’t turn out? If you’re a bad cook, then you will likely struggle with machinery repair. If you enjoy cooking and everything turns out great (exactly like the photo, you look forward to making it again, people ask you to cook at events, they want your recipies, etc.) then you won’t have any trouble repairing machinery.
Definitely don’t run the saw until it is fixed.
Thanks,
Ed