Easy
Less than 15 minutes
This is an individual screw used on various models of chainsaws to fasten and secure the drive sprocket, located beneath the chain cover around the guide bar. Both the chain cover and guide bar need removal to replace this screw. Made of high-quality metal, this screw is an M5X8.5 left-hand OEM screw designed to secure a washer (sold separately) to the primary drive sprocket, ensuring its retention within the chain drive. For optimal performance, it is recommended to replace both the screw and accompanying washer simultaneously to maintain a secure connection. If your drive sprocket is stripped, worn down, or any part of this assembly is damaged, consider replacing this screw to effectively secure the sprocket, washer, and chain drive.
Screw 90639221
OEM part for: DeWALT
Part Number: 90639221
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Compatibility
This Screw will fit the following 6 machines. Confirm this part works with your model, and view the detailed model diagrams and repair help we have to offer.
DeWALT
Show More Compatible ModelsThis item works with the following types of products:
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Customer Repair Instructions ?
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.
Chain wouldn't stay on the sprocket
Tool Type
Chain Saw
Difficulty
Easy
Time
15-30 minutes
Tools Used
Power Drill, Wrench Set, Bench Grinder
Parts Used
Anyway. Even with the replacement bolt there is a gap between the bolt head and sprocket, so I drilled out a washer and ground it flat to put additional pressure on the outside edge of the sprocket and take up the gap between the bolt head and gear. Ran the chainsaw for another couple of hours, no further issues.
The sproket was worn and the bolt had snapped.
Tool Type
Chain Saw
Difficulty
Medium
Time
Less than 15 minutes
Tools Used
Screwdriver
2. I removed the broken bolt.
3. I then removed the plastic plate holding the sprocket in place.
4. I then slid off the worn sprocket, replaced it with the new sprocket, installed the new washer, and bolted it on with the left threaded screw.
5. Then I put everything back together.
chain detached from sprocket
Tool Type
Chain Saw
Difficulty
Medium
Time
15-30 minutes
Tools Used
Power Drill, Socket set
Parts Used
cleaned parts of accumulated sawdust
replaced washer and LEFT-handed screw to sprocket shaft
reinstalled bar with chain
Reverse thread screw broken off in shaft assembly. Had to replace both.
Tool Type
Chain Saw
Difficulty
Medium
Time
30-60 minutes
Tools Used
Screwdriver, Pliers, Socket set
Parts Used
Remove all parts under cover.
Remove rear handle.
Remove inner cover.
Remove shaft assembly.
Reverse order to reassemble.
Note!!!!!! Do not disasemble saw until you receive your parts. Its hard to remember how it
goes back together two days later. Not easy job at that point.
Lost the screw and washer on the chain sprocket
Tool Type
Chain Saw
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Screwdriver, Pliers, #15 star bit long reach
Drive Sprocket striped
Tool Type
Chain Saw
Difficulty
Easy
Time
15-30 minutes
Tools Used
Screwdriver, Socket set, Nutdriver
2 removed the sprocket
3 replaced sprocket
4 reassembled the cover and replaced chain and bar
drive sprocket damaged
Tool Type
Chain Saw
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Wrench Set
Drive sprocket stripped
Tool Type
Chain Saw
Difficulty
Easy
Time
15-30 minutes
Tools Used
Screwdriver, Pliers, Power Drill, Nutdriver
Washer and screw were missing causing the chain to come off.
Tool Type
Chain Saw
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Screwdriver
Parts Used
Bolt broke off. Had to remove and replace
Tool Type
Chain Saw
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Adjustable Wrench
Parts Used
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Our customer service team are at the ready daily to answer your part and product questions. We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.
All our part reviews are solicited directly from other customers who have purchased this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
Based on data from past customer purchasing behaviors, these parts are most commonly purchased together along with the part you are viewing. These parts may be necessary or helpful to replace to complete your current repair.
All our installation videos are created and produced in collaboration with our in-house repair technician, Mark Sodja, who has helped millions of eReplacementParts customers over the last 13 years repair their products. Mark has years of experience in selling and repairing both commercial and residential products with a specialty in gas-powered equipment.
This data is collected from customers who submitted a repair instruction after replacing this exact part. Customers can rate how easy the repair was to complete and how long it took. We aggregate this data to provide a repair rating that allows customers to quickly determine the difficulty and time needed to perform their own repair.
