Doug Hobkirk
04-28-2014, 4:39 PM
I bought a Delta Sawbuck for $40. Very good condition. We plugged in the motor and it sounded OK. After getting it home, the motor would sometimes not turn on with the switch. Bad switch? Wiring? Motor problems? Brushes?
So I dismantled things enough I could clip my VOM leads on the ends of the soldered wires running to the brushes. (The front bearing and gear reduction unit have been removed.)
Then I activated the switch several times - the motor response was intermittent, and would not run more than a few seconds. Sparks. The VOM confirmed voltage.
Question 1 - Does this indicate probable bad brushes?
So I figure it is probably the brushes, although there's nothing that looks beat or worn-out or abused. Even the 8" Delta blade (it looks original) looks decent. The seller said he used it for one job. This is what a new brush looks like (http://www.ereplacementparts.com/brush-and-spring-p-68142.html?osCsid=8uk63t9o1hg1vml97v0i10fgt0). This is what they looked like for a CWMoser in another forum:
288272
And this looks like what I am chasing.
I removed the brush covers but I could not get the brushes out - I did not pull really hard.
I can see the tip of my most tiny long needle-nose pliers reaching the armature.
I avoided having the copper "cap" of the brush assembly obstructing my pliers.
Twisting and pulling the pliers doesn't seem to do anything.
After studying the above picture, I went out and tried some more "normal" needle-nose pliers (I probably have 20-30 different ones). But none could pull the block out.
Question 2 - Should I hit the area under the coiled wire with a penetrating oil like PB Blaster?
I have tried getting a screwdriver on the armature end of the brush to no avail. I don't know how fragile the "commutator bar" is, so I did not get aggressive.
Maybe if I remove the armature assembly (I don't really know if this is possible) I could push the bushings out.
I removed the screws from what I assume is a rear bearing - I can rotate it independent of the armature shaft but I was not able to pull it off. Again, I did not get aggressive.
Question 3 - Is it OK to get aggressive?
But maybe this last strategy is a fool's errand. I did try to remove the two Phillip head screws the seem to hold down a plate at the other end of the armature and they did not want to budge. I am pretty sure I felt one start to go soft. I can deal with stripped screw heads if necessary, but naturally I would prefer to avoid the significant hassle.
I have reached my level of incompetence. Can you help me?
DELTA SAWBUCK NOTE - The Sawbuck impresses me. It cuts up to 14" wide and 2.5" thick stock. The angle adjustment scales are huge - maybe 1/4" per degree! Clever engineering, adjustments possible for just about every piece, etc. The fences are adjustable, the miter range is 47 degrees R or L. The whole saw slide assembly is very solid with an excellent pivot point. And it tilts (only to the right) up to 45 degrees. The blade is 8".
I bought it ($40) to give a contractor that I owe a favor - he recently noted he didn't have a table saw and wished he did (he's really into working metal, not wood - a good table saw would be a poor use of his shop space).
I believe someone in this forum said it would be excellent for a siding or trim contractor. The only problem might be that the wood (or plastic) must be fed in from the side, something I hadn't thought of.
288271
So I dismantled things enough I could clip my VOM leads on the ends of the soldered wires running to the brushes. (The front bearing and gear reduction unit have been removed.)
Then I activated the switch several times - the motor response was intermittent, and would not run more than a few seconds. Sparks. The VOM confirmed voltage.
Question 1 - Does this indicate probable bad brushes?
So I figure it is probably the brushes, although there's nothing that looks beat or worn-out or abused. Even the 8" Delta blade (it looks original) looks decent. The seller said he used it for one job. This is what a new brush looks like (http://www.ereplacementparts.com/brush-and-spring-p-68142.html?osCsid=8uk63t9o1hg1vml97v0i10fgt0). This is what they looked like for a CWMoser in another forum:
288272
And this looks like what I am chasing.
I removed the brush covers but I could not get the brushes out - I did not pull really hard.
I can see the tip of my most tiny long needle-nose pliers reaching the armature.
I avoided having the copper "cap" of the brush assembly obstructing my pliers.
Twisting and pulling the pliers doesn't seem to do anything.
After studying the above picture, I went out and tried some more "normal" needle-nose pliers (I probably have 20-30 different ones). But none could pull the block out.
Question 2 - Should I hit the area under the coiled wire with a penetrating oil like PB Blaster?
I have tried getting a screwdriver on the armature end of the brush to no avail. I don't know how fragile the "commutator bar" is, so I did not get aggressive.
Maybe if I remove the armature assembly (I don't really know if this is possible) I could push the bushings out.
I removed the screws from what I assume is a rear bearing - I can rotate it independent of the armature shaft but I was not able to pull it off. Again, I did not get aggressive.
Question 3 - Is it OK to get aggressive?
But maybe this last strategy is a fool's errand. I did try to remove the two Phillip head screws the seem to hold down a plate at the other end of the armature and they did not want to budge. I am pretty sure I felt one start to go soft. I can deal with stripped screw heads if necessary, but naturally I would prefer to avoid the significant hassle.
I have reached my level of incompetence. Can you help me?
DELTA SAWBUCK NOTE - The Sawbuck impresses me. It cuts up to 14" wide and 2.5" thick stock. The angle adjustment scales are huge - maybe 1/4" per degree! Clever engineering, adjustments possible for just about every piece, etc. The fences are adjustable, the miter range is 47 degrees R or L. The whole saw slide assembly is very solid with an excellent pivot point. And it tilts (only to the right) up to 45 degrees. The blade is 8".
I bought it ($40) to give a contractor that I owe a favor - he recently noted he didn't have a table saw and wished he did (he's really into working metal, not wood - a good table saw would be a poor use of his shop space).
I believe someone in this forum said it would be excellent for a siding or trim contractor. The only problem might be that the wood (or plastic) must be fed in from the side, something I hadn't thought of.
288271