Electric Power Tool Parts 101
This article defines the basic parts of most power tools, explains how they work, and what to look for when they stop working.
Diagnosing Electric Power Tools 101
This article is a troubleshooting guide for problems and malfunctions common to most electric power tools.
Discussion
Discussion for the Skil HD77 TYPE 17 Worm Drive Saw
I have a 25 year old HD77 that has only an hour or two of use. All of a sudden the blade stops when I try to cut anything even though the motor runs fine. I changed the oil as recommended with no change. What gives?
Hi Sparky,
If the out put shaft has stops spinning while the motor runs try removing the bearing end plate and see if armature nut has lost its torque. The nut keeps pressure on the worm gear.The worm gear has no key way and is kept tight by the nut. If the nut is loose the armature shaft will just spin in the gear. I know you've check to make sure that the blade screw is tight so I won't mention that.Hope that helps.Good luck.
Tinker
Reply: Skil HD77 Type 16
Sparky1
Tinkerdave, the nut that keeps pressure on the armature shaft was loose. Works like a champ. First one of these critters that I have owned and I'm not that familiar with it. Many thanks, Sparky1
Hi,
I own a skil model 77 type 17 that is approx 20 years old but, lightly used and in great condition. I was cutting some stringers for some stairs out of 2x12's and all of the sudden it quit working. It made a sound like it was under water and then quit working.
Its funny right before that I thought to myself "this is a bad ass tool, its never let me down" FYI don't ever say that to yourself about anything otherwise it quits working.
Anyway....I had it plugged it to a long 14ga extension cord, and I think I overheated the switch. Later when I took the handle apart to look at the switch, it looked like the bottom of the switch was cooked a little and the wires that are attached to the armature were melted at the switch, one of them was severed all the way through.
Since I can't take the saw farther apart without alot more effort, I am asking if anyone knows if the armature wires can be replaced or are they molded into the armature ?
Do I have to buy a whole new armature if the wires are messed up ????
ok, so nobody replied... I'll get over it....
Here's what happened...
I ended up ordering a new switch, 8' cord and handle.
I soldered a wire with a terminal on it from the old cord to the wire that was melted put it all back together and she worked !!!
maybe get another 20 years out of it !!!:cool:
Has anyone tried substituting type 17 worm gears in a type 16 skilsaw? I have a model 77 '50th anniversary issue' worm drive and the gears are shot. Apparently the type 16 gears are no longer available, but since these saws didn't change much over time, I'm hoping the newer ones fit. Anyone?
Hi Kent,
In answer to your question. The type 16 and type 17 gears are both different sizes and the housings are not the same. You might try some local repair centers to see if they have any of the older gears.
WJA
After removing housing that contains the brushes, screw off the plastic cap on the front of the saw with a 1 1/8" socket. Then remove the locking nut from the end of the armature. Then using a 1/2" or 5/8" brass rod, gently drive the armature out of the front bearing.
The owners Operating Guide ask me to change the oil in the gear case using Skil oil P/N 80111 or 80112 or 80113. Do you have any idea where I can get any of this oil?
How do you remove the lower blade guard in a Model 77. I assume the retainer ring holds it. Mine seems so tight and it is a bit hard to figure out how to spread the ring to remove it.
The ring comes off by finding the split and lifting it with a thin flat blade and spreading it open in a clockwise direction.
Don't mistake the black ring for the silver part of the blade guard.
Skil offers an oil specifically for the worm drive saws. That is the oil we use here in our shop. It is part #80111 and is available from http://www.ereplacementparts.com.
I have a 77 super duty (the handle is part of the motor housing) ser #676063. Is the part #78 on the diagram the same dimensions as for this older model? What I need is a seal (retainer) to replace a CR 6570, the # on the seal in my old saw.
I just inherited a HD77 Type 15 saw. The extension spring is missing so the lower guard is loose and therefore it is hazardous to operate the saw. My question is how do I hook up the spring?
One end of the spring is flared the other has a hook on it. Thread the spring through the small hole located near the center of the lower guard. Pull the spring through the hole so that the flared end contacts the lower guard. Now you can attach the hooked end to the connection point on the inside, top, of the upper guard. Whit that the guard should now be functional.
My HD77 has leaked oil. I haven't discovered the source of the leak yet but want to repair it before I use the saw again to prevent additional damage. Any ideas on where and why oil is leaking?
Two of the more common areas we see leakage on the HD77 saws are the rear seal, item #78 on the parts diagram, or loose screws on the Guard Plate, item #1619X01255 on the parts diagram. After you diagnose and repair the leak, refill the saw with Skil Worm Gear Oil, part #80111. Hold the saw level and then fill the gearbox until the oil comes up to the bottom of the threads on the fill spout.
I hope this helps with your repair!
-Mark
Reply: Oil Leak
Ronald Cox
Is there a Worm gear oil substitute for part #80111 available?
My question is not really a repair question, but I'd like to know what type of oil is supposed to be used in these saws? and would it hurt the saw if I but lithium grease in it instead of oil?
Skil has a gearbox oil that is specifically for the worm drive saw. It is part #80111 and is available from http://www.ereplacementparts.com.
You do not want to use lithium grease in the gearbox. The worm drive saw requires an oil bath for lubrication. Grease will be flung off of the gears and will not lubricate them.
Excessive sparking inside the rear vent holes is caused by an armature that has gone bad. The armature has shorted out and is now arching. The armature shorted out due to excessive load, usually caused by the type of work that was being done or by an extension cord that was too long and its wire gauge too small. The armature will need to be replaced. Many times when an armature is damaged the field will be damaged as well. You will want to have the field tested to see if it was damaged.
Unfortunately the armature and field have been discontinued for this version of the hd77 saw. You will likely need to replace the saw.
My neighbor gave me a gift of a relatively new Skilsaw HD77 worm drive saw. That he said doesn't work.
In reality it does 'work' except that it produces a lot of sparks coming from the armature end. I checked the 2 brushes and they seem to have a significant amount of material left.
Before I take the saw apart, I thought that I should check this group's wisdom on most likely causes so that I spend my time and money wisely.
hello! if the carbon brushes are good check the commutator bars for burns, distorted, loose bars also check between each bar gap make shure there is nothing in between causing a short. also check the armature for burn marks or delamination. and last check the field for damage and burn marks of discolering. good luck!
The pivot plate that the bearing is seated in broke on my Skilsaw HD77 saw and I have to pull the bearing off to put on another pivot plate. Can I remove the bearing from the shaft with just a basic puller? If anyone has had to replace bearings or worm gears your input would be much appreciated.
I am looking for some parts on a skilsaw. I can't seem to find the right model number on the parts page. The model number is a 77 not the HD77. serial #1B504000. This is an older saw. What I am wondering is if the the parts are the same? What model number is the closest?
Thanks Paul
I had a saw just like yours, but parts were getting harder to obtain, alot of the parts are no longer available. But I do have the parts list. Ill attach it here.
Good luck!!
I have a Skil HD77 circular worm drive. In using the saw I was cutting a redwood
4x4 with a new blade the saw just stopped running. I have done all the simple checks
power cord,oil level,ect no burnt wires or smell. Anyone have ideas what too look for before I tear it apart?
Thanks,
Sammy
With the saw suddenly dieing like that I would suspect either the brushes or the switch. Check the brushes first. If they are almost worn away then they are probably the problem. If the brushes look OK then open the handle and inspect the switch. You can test the continuity of the switch with a multimeter set to test ohms.
I have a Skilsaw Model 77, type 16 (in fact it's the '50th anniversary issue'. I need to replace the worm gears. Are they available? Can I use the ones listed for the model 17?
The gears for the type 16 and type 17 are different and not interchangeable. Unfortunately the manufacture has discontinued the parts for the type 16. So either find a type 16 with good gears or time to purchase a new one.
I've been an REO contractor for more than 28 plus years. I've used the same saw for all that time. No other can or will do all the things I ask it to do. I make my living on this saw's reliability. It has NEVER let me down
i love this saw it is indestructible!! ive had it for about four or five years now and the only two things ive had to replace are the cord after a co worker cut it and now a trigger which is what brings me here my deck is bent a little also.
This is the best framing saw out there. It's heavy, but the balance is spot on. I have had several of these for over 10 years, and they run like the day they were new. I would never recommend another framing saw, the HD77 is all I need. I really hope Skil never changes anything on this saw.
L have owned and used this saw on construction sites, home repair and general wood cutting projects. It has served me well for 20 or so years and finally I must replace the trigger switch. The only maintenance ever done to it was to drain and replace the gear oil every two years, more often under heavy use. I have used it with a diamond blade to cut cementious siding and ceramic floor tiles. I have absolutely NO COMPLAINTS about my Skilsaw! Rather, I lavish praise on it for its' toughness, its' power and stability in use under harsh conditions and in the poshness of a workshop. It has never let me down.My only regret is that the magnesium model was not available at the time I made my purchase. I still cannot justify replacing it with anything else!Love it, Love it, Love it!11/09/2008
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