Scrollsaw Workshop Community -Please register to enable posting.
General Category => General Scroll Saw Talk => Topic started by: KarlB on February 14, 2017, 07:47:08 pm
-
Has anyone changed out the brushes in their DeWalt saw? If so, what actions in the saw preceded the change? Also how long had the saw been in use before changing the brushes? (in years)
I've just ordered some brushes to replace mine which are about 9/16" long.
Thanks for the replies,
Karl
-
Carl the motors on the Dewalt generally will short out the armature long before you need to replace the brushes init. The brushes in my opinion too soft for the use that it is being asked to do. The carbon dust builds up and shorts out the armature of the motor causing it to fail. Some of the symptoms are the inability to maintain speed ( speeding up and slowing down on its own ) not starting until you move the arms a bit to get the motor to start. Sometimes it will just blow the fuse. The best way to do this is to actually remove the motor from the saw and open it up and blow out the carbon dust and ensure that the armature is clean before you put it back together and then replace the brushes.
DW
-
Karl
What DW says is correct and a periodic clean will help the motor last much longer
however you say that your current brushes are about 9/16 long, I have just measured a brand new one and it is only about a 1/32 longer than that so am doubting that what ever problem/ symptoms you have are brush related
Dave
-
Thanks DW and Dave.
Your advise and insight is well taken. Too bad I didn't consult here first. (I probably wouldn't have bought the brushes.)
That being said I guess I'll be taking the saw back apart and doing what you said DW - cleaning out the motor.
...not starting until you move the arms a bit to get the motor to start.
That's what I was experiencing as well as the motor "stuttering". Since I have a foot pedal I knew it wasn't the switch and the only other electrical I could "relate" to was the brushes. I've changed out brushes in my Dewalt table saws and miter saws before so I figured - why not?
Getting the saw apart and back together is a pain and sometimes I could use 3 hands!
Any other advise will be appreciated as I won't be taking it apart until Saturday.
I took out my older Craftsman saw but it sucks on the blade clamping system. I guess I forgot how bad it was before I got the DeWalt. Can't wait to get "Old Yellow" back in business.
Karl
-
Karl while you have the saw apart you may wish to put a bit of grease on the moving bearings. I know they claim to be maintenance free however it still is a good idea. Look for free floating metal shavings while you have it apart as well. A good preventative maintenance now and then can keep your saw up for a long long time.
DW
-
Yes good tip for greasing everything - I did that last time I had the saw apart fixing something else.
I'll start into looking into the problem tomorrow night.
Karl
-
Well I started taking the saw apart and encountered a problem getting the housing off the motor. I used an impact driver/drill to loosen the screws.
Before this I noticed the motor (under no load) only started at two positions (opposite of each other). I removed the housing after removing the brushes and cleaned the commutator lightly with 1500 grit sandpaper. I also flattened out the brushes.
So what's happening now is the motor starts (under no load) at any position, but it is not as fast as I believe it should be. Plus it is stuttering a bit as it goes round.
Is this because the brushes are now flat and not curved thus decreasing the surface contact with the commutator and thereby having decreased speed?
I am waiting for the new brushes and hopefully this helps.
While waiting for the brushes I disassembled as much of the saw as possible and have cleaned and lubed the needle bearings where I could get to them. I noticed a couple of the sleeves could be replaced. I could not get to a couple of the bearings unfortunately.
I did get some help from Bob Brokaw's (Gwinnett Woodworkers) videos on Scroll Saw Maintenance on YouTube. This is good information even if you don't plan on doing your own maintenance.
Karl
-
I received my new brushes today and have started putting things back together.
(One word of wisdom here. It's best if you disassemble and reassemble the saw within the same day. Since my memory "ain't what it use to be" I had to keep consulting the exploded view to put things back in order!)
First as Dave noted the new brushes were only 1/16 longer than my old ones and that's probably due to my sanding of the old ones.
My next problem after putting the motor back together and turning on the switch - it through the breaker. Back to disassembly of the motor again. Low and behold there was a wavy washer half mangled near the armature of the motor. Not exactly sure where it came from as the one that goes around the main bearing is still in my parts cup. I believe it went between the motor housing and the lower sealed bearing. So I put it there and tried again - no success. (BTW, the lower bearing spins a bit rough and probably should be replaced.)
I then removed the wavy washer from the motor and tried the motor without any thing connected and finally got it to work by moving the motor around again - same problem as before. So I reattached the upper and lower arm assembly and temporary screws attached to try the motor with attachments.
Well again it would only work if I moved the arms up or down. It will constantly run like this, but it has stutters still. It seems to me this is still electrical in nature.
I'm starting to run out of options.
Any advice anyone?
Karl
-
I suspect there is an armature issue, or one of the field coils is lazy. If the armature has a shiny section it may be rubbing on the field coils. or, there could be broken winding wires hidden inside the coils, worn out bearings could cause this condition or the crushed washer you found may have damaged the windings. An electric motor rewind shop would be able to diagnos this. to fix that would be a new motor. A new motor from Dewalt would probably be quite pricy..
-
Thanks Norm for the tip.
I took the motor to our local armature works. Bench charge is $32.50 but will be applied to any repair if wanted. Will find out next week.
Karl
-
Glad I could help. Happy Scrolling
-
Thanks Norm for the tip.
I took the motor to our local armature works. Bench charge is $32.50 but will be applied to any repair if wanted. Will find out next week.
Karl
A new motor for that saw is in the $285 dollar range last time I looked.
DW
-
A new motor for that saw is in the $285 dollar range last time I looked.
Yeah that's what I'm afraid of - a new motor. I'm watching one on Ebay for $140 and an online parts supply is $296 (both plus shipping). I'd be hesitant on the first one and not likely on the second.
At $300 for a new motor I would just buy a new machine and save this one for parts.
I'm pondering at what price point on repair or replace do I repurchase?
Karl
-
Dewalt has a Guaranteed Repair Price program- somewhere around $270 if memory serves me correctly. I used that when my motor died and had them do a complete overhaul and tune up on the saw. I would only do it once though. Next time is a new saw and this one will be parts.
The other thing I have been contemplating is modifying the saw ( after the motor dies ) and make it a direct drive belt system. I have the parts and the knowledge to do it... just a matter of wanting to hehe.
DW
-
Dewalt has a Guaranteed Repair Price program- somewhere around $270 if memory serves me correctly. I used that when my motor died and had them do a complete overhaul and tune up on the saw. I would only do it once though. Next time is a new saw and this one will be parts.
The other thing I have been contemplating is modifying the saw ( after the motor dies ) and make it a direct drive belt system. I have the parts and the knowledge to do it... just a matter of wanting to hehe.
DW
Are you saying DeWalt would repair for that amount? And I guess if only under warranty still?
I thought the same thing for the old saw. I don''t have the parts or knowledge, but I did watch McGyver a long time ago. :) Actually I could probably figure something out, but I want to get back on the saw sooner than later. I looked again at my "backup" craftsman to see if I could modify the blade holder, but it will take changing their clamping system.
Thanks DW.
Karl
-
Maybe some of the DeWalt Service Centers actually take the saw completely apart, clean and repair it as their website states, but I took one of mine to Seattle - twice - and it came back in the same condition as when I took it...both times.
I'm currently considering purchasing another Jet, just in case they discontinue making it due to so many bad reviews. If people correctly learned how to use the new blade clamping system, it's a fantastic saw.
Nancy
-
Dewalt has a Guaranteed Repair Price program- somewhere around $270 if memory serves me correctly. I used that when my motor died and had them do a complete overhaul and tune up on the saw. I would only do it once though. Next time is a new saw and this one will be parts.
The other thing I have been contemplating is modifying the saw ( after the motor dies ) and make it a direct drive belt system. I have the parts and the knowledge to do it... just a matter of wanting to hehe.
DW
Are you saying DeWalt would repair for that amount? And I guess if only under warranty still?
I thought the same thing for the old saw. I don''t have the parts or knowledge, but I did watch McGyver a long time ago. :) Actually I could probably figure something out, but I want to get back on the saw sooner than later. I looked again at my "backup" craftsman to see if I could modify the blade holder, but it will take changing their clamping system.
Thanks DW.
Karl
Nope anytime.. At the time my saws warranty was gone by almost a full year. There Guaranteed Repair Price Program is on all repairs out of warranty the price is guaranteed not to exceed the quoted estimate. I has asked them to go over the saw and had that in the contracted quote this way I could get any bearings or other things replaced while they had the saw and had it apart.
DW
DW
-
Well after not hearing from the armature place I decided to call them. A male answered and had obviously worked on it by his knowledge. He said the "armature has an open circuit". That it could be rewound, but would have to be sent out (I thought they did that here) and it would cost around $200! Too much for this saw.
He said he has abut $60 plus time into the motor as he also turned the armature to make sure the commuter was true. (Something I did not authorize.) He did ask a rather strange question: "Are you planning on throwing it away?" I told him no and I'd be in this week to pick it up. I'm can only speculate as to why he asked the question and the only thing I can come up with as he (the company) would keep the motor and effect a repair and resell the motor later.
I hope I have no problem just paying their bench charge tomorrow when I pick up the motor!
Any thoughts?
Karl
-
I personally would get the motor and see if I could find a used saw in craigs list that has problems other than the motor and us it for parts. In the mean time you could use the GRP program at the Dewalt service center or just purchase a new saw and use that one as a parts source for the new one. The GRP program would be the cost of a brand new motor and it would be installed by factory trained folks it would be somewhere close to $280 I believe.
DW
-
I agree with you DW on the looking for a old saw, but I'm getting itchy to get back on the saw.
I can't seem to get over a new motor at $280 plus when at that point I'm three-fifths of a way to a new saw. I am still contemplating the new motor from Ebay and that seller has great ratings, but again at $140 I am one-fifth of the way to a new saw.
I know I need a few needle bearings and sleeves so there's a bit more cost as well.
One idea I have is not taking my vacation from last year (that I missed) and seeing if my boss would give me the money instead and I would still keep working, thus giving me two weeks pay in one week. This would give me immediate infusion of money to purchase a new saw! Just thinking out loud!
Karl
-
It is worth it, one time, to get the GRP repair at the service center after that then you might wish to consider a new saw. If you decide to do the GRP ( guaranteed repair price ) at the service center make a detailed listing of things you want done.. might as well have them lube, clean and replace any worn parts that you know about when they are replacing the motor. Just a thougth :)
DW
-
Well I got back the motor today (it was all apart without the bearings attached) and it cost $45 with tax. He said there was a broken circuit somewhere in the windings.
After I inspected the parts at home I kinda think the insides were not from my motor. I know this seems "conspiracy-ish" but I know I sanded my commuter and the one I got back was not sanded. Anyway there is absolutely nothing I can do to prove anything so I must put it aside and move on.
A word of wisdom for anyone else (and for me in the future) - mark your stuff in an inconspicuous spot. I should have done that when I had it a part. Live and learn!
So my next step is going to be a new saw...which I just ordered a few minutes ago!
See the topic here: http://www.stevedgood.com/community/index.php?topic=19965.msg176655#msg176655
(ftp://www.stevedgood.com/community/index.php?topic=19965.msg176655#msg176655)
Karl
BTW, thanks to everyone above for the great advise. It is well appreciated!
-
Just thought I'd post this and maybe someone now or in the future will find it useful. Reading this thread and seeing what members were sayin about the price of a new motor for a Dewalt/Delta saw. Is this a good deal? If so might be worth repairing the old saw for a backup.
http://www.ebay.com/itm/DeWALT-DW788-DELTA-40-690-RECIPROCATING-SCROLL-SAW-MOTOR-ASSY-286306-00/321947331282?_trksid=p2060778.c100290.m3507&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D40954%26meid%3D9c4108362ffc44839134d886c3a67d26%26pid%3D100290%26rk%3D1%26rkt%3D4%26mehot%3Dlo%26sd%3D321947331282
-
Yeah that was the one I was watching when there was one left. (Just a couple of days ago.) Up above I mentioned that motor, but at $140 plus shipping that is still one quarter of a new saw. Plus I would still need bearings at some point.
I decided to spend more money and get a new one with a good warranty as well.
That being said that looks like a good seller and it appears they have sold 18 of them. When I looked for completed sales however I couldn't find past sales.
Anyway I think that would be a toss up for a lot of people.
Karl