Arbor Repair – Delta Contactor Saw
sawdustom
| Posted in Power Tools and Machinery on
I’ve read most of the message threads in this forum regarding arbor flange runout. My 20 year old Delta Contractor saw is generating .011″ of runout at the blade tip. I measured this using the A-Line-It kit.
Can a reasonably skilled person replace the arbor on a Delta Contractor saw? I’m assuming I can get the parts from Delta but how about some useful instructions? Is there a good FWW article or book I should consult?
If the shaft is OK is it worth taking it to a machine shop to have the arbor flange trued up?
Thanks in advance – this forum is a great source of help!
Replies
Last year,I replaced the shaft and bearings on my 1960 ish Delta Unisaw. The biggest part of the job was removing the heavy table and wings single handed. The shaft was worn from the putting on and taking off all the blades and cutters these many years. While I was at it, I also replaced the pullys and the 3 belts. Now you can hardly hear the saw run.I wish that I had done this job a long time ago,but I guess that I am a putter-offer.I am not familiar with the contractors saw,but I would think that the mechanics would be similiar.Thank you,Mr.Croney,where ever you may be.
Work safely ¬¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬¬
Edited 11/8/2004 11:56 pm ET by Pat
It's hard to say but it's not that big a job to do it but it depends on your background and finding a reasonable machine shop tpo work with.
http://www.sawcenter.com/unisaw.htm This covers a Unisaw arbor replacement. The contractor saw is more of a pain. It's best to flip the saw over to work on it.
http://www.cambiumbooks.com has a good selection of books on machine but I don't know if there is one that deals with the contractor saw.
Go to http://www.owwm.com You will find other folks wrestling with the same issues. Kind of long winded and topics tend to get beaten to death and there is some bad and misleading info but it's overall intent is good and it will give you the support you seek.
Are you sure the arbor needs to be replaced? Runout at the blade tip could be caused by a number of things, a bad arbor being the least likely cause of the problem.
John W.
John is correct. All blades have runout and the true way to check your arbor is to use an indicator at the flange. I suspect your saw is fine. Checking runout at the tip would hardly be a conclusive or definitive test.
The A-Line-It has a neat system for measuring arbor flange runout. There are two methods for measuring runout.
1. You can measure runout directly on the arbor flange using the dial indicator. This works but as others in this forum have pointed out, you need a really good dial indicator to measure arbor flange runout directly. I did measure the arbor flange directly and it showed some runout (~ .0016). Runout measured at the arbor flange will cause about five times as much runout at the blade tip.
2. In this second test a blade (and washer) is placed on the arbor and held in place with a special "nut" that uses a spring to push the blade tight against the arbor flange. In this arrangement, the blade can be held in a fixed position while the arbor is rotated.The dial indicator is set to read just below a blade tip. Rotating the arbor while keeping the dial indicator measuring the same point on the blade gives a measurement of blade tip runout caused by the arbor and eliminates any interference from the blade. This test showed about .011 of runout.
BTW - the second test also lets you measure pure blade runout without interference from the arbor flange. My Freud 80t plywood blade measured about .005" of runout.
As a follow-up question - is .005" of blade runout excessive? Is there any way to fix blade runout?
.005" is acceptable. You are talking woodworking not space shuttles. Veritas made a blade truing but it didn't last very long before being discontinued.
http://www.leevalley.com/wood/page.asp?SID=&page=30077&category=1%2C41080%2C41162&ccurrency=2
I've been in the industry professionally and see more hobby guys worry about tolerances are well within acceptable standards and especially for Unisaws and such. CNC routers and 4 sided moulders are of a different nature but so is $100,000 machine versus a $1,500 saw.
Don't these indicator companies give some kind of guidelines of what is acceptable? Seems to me if they are going to give a tool to give accurate readings to .001" they should give some kind of list and explanation of more than how to use it.
Edited 11/9/2004 3:01 pm ET by rick3ddd
I agree that .005 on the outer part of the blade is acceptable. I have a 1950 Unisaw with less than .001 at the arbor but with my best blade (Freud Ultimate Cut-Off) it's right at .004 right up near the teeth.
I was able to improve the arbor runout on this machine by applying pressure with a piece of scrap wrapped in 180 alum. oxide paper to the face of the arbor with the saw running. Cleaned it up real nice and reduced runout from almost .002 to less than .001; might be worth a try on yours but you're really fine where you're at.
Regards,
Mack"WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"
Update on Arbor RepairI was able to true up the arbor flange on my saw using a combination of sandpaper, files and patience. It took about an hour but I got the flange to less than .001 of runout. This took the blade runout to less than .004. The results are fantastic. Between the arbor flange improvement and saw realignment it has never cut better. I am amazed at how much easier stock feeds and how smooth and burn-free the cuts are.Thanks to everyone for your advice and guidance.
Gives you a warm fuzzy feeling to spend an hour of toil and sweat and know that every time you use that machine it's going to pay off again---and again. Nice work!!
Regards,
Mack"WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"
Whoa, I would be surprised if the problem is with the arbor. If you are measuring at the tips of the blade, you are measuring the total runout of both the blade and the arbor. In fact, it is more likely that the problem is more with the blade than the arbor. It takes quite a bit of abuse to materially affect the trueness of the arbor. The only one I have seen damaged was caused by a weight lifting weight being dropped on the saw. Both the blade and arbor were damaged.
If you want to determine arbor runout, measure against the rim of the arbor without the blade attached. Also, run your finger around the arbor and see if there is a burr or raised spot. If so, use a file or emery paper to smooth it.
Blades are easily distorted. One way is to tighten the blade too much. Tighten a blade only as much as you can when you hold the blade with your fingers. Do not wedge anything against the blade to hold it.
Howie,"If you want to determine arbor runout, measure against the rim of the arbor without the blade attached." This is exactly what I did. I have a dial indicator and a jig that lets me position its measuring point against the rim of the arbor flange. I carefully marked the high point and the two other points where it returned to level. Using a file, sandpaper/block I was able to level out the flange. It certainly isn't perfect but the difference between the highest point and lowest point is now less than .001" versus before where it was greater than .003".
tom,
That really is close enough! Less than .001 runout at the arbor flange more than likely puts you in better shape than almost any mfg. tolerances as they leave the factory. Your patience has been rewarded.
Enjoy!
Mack"WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"
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