Easy
30-60 minutes
It is a genuine manufacturer-sourced item which is specially designed for use with MTD blowers and chippers. This replacement thumb screw has a few different applications depending on the model of your unit, please refer to appropriate diagrams for correct location and use of this hardware. It is a high-quality item which is made of durable metal with plastic and it is sold individually.
Knob-three Arm 720-0170
OEM part for: MTD
Part Number: 720-0170
$11.34
In Stock
Order within the next 13 hours and your part ships today! 
Compatibility
This Knob-three Arm will fit the following 6512 machines. Confirm this part works with your model, and view the detailed model diagrams and repair help we have to offer.
Displaying 20 of 6512 matching models.
6512 total model matches. Try the above search to narrow your results.
This is the official OEM part for the following brands:
- Craftsman
- Cub Cadet
- Husky
- MTD
- Troy-Bilt
- Yard Machines
- Yard Man
This item works with the following types of products:
- Blower
- Chipper / Shredder
- Lawn Tractor
This part replaces obsolete part #: 681-0048
Customer Part Reviews ?
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hard to find parts
was so easy to order. Had the parts for a Craftsman that could not be found locally. Shipping cost was fair. Have EReplacementParts on my favorite list as I am sure I will ordering from them again.
Guest -
June 13, 2020
Verified Purchase
Item as advertised.
This item goes on my MTD chipper. Not really much to say. It keeps the discharge chute from moving so I can make mulch for my wife's many plants. It was delivered relatively quickly.
Guest -
September 24, 2019
Verified Purchase
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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.
the chipp[er wasn't used for over two years - lots of rust.
GLENN - December 1, 2021
Tool Type
Chipper Shredder
Difficulty
Medium
Time
1-2 hours
Tools Used
Power Drill, wire feed welder, hand shears, zip disks
Parts Used
1. Checked gas and oil. Added some fresh gas - oil was OK.
2. Choked and pulled the starter cord. Engine turned over but cord didn't retract.
3. pulled engine cover off and sprayed WD-40 on end of snout. Balls freed up. Replaced the cover and pulled cord twice and the engine started. I let it run for 10 minutes.
4. The discharge chute hand knobs were totally rusted solid. I used a zip disk to remove then drilled out the remaining threaded part and ran a tap to establish new the threads.
5 Ordered a pair of hand knobs. Made a pair of temporary pieces from 5/16 bolts with a 2 inch piece of 1/4 inch round rod welded on the head.
6. I changed the direction of the discharge chute so it was more parallel with the ground. I modified the top of the chute by cutting each side at 2 inch intervals so I could flatten the top.
I made new sides from a piece of old washing machine sheet metal, drilled 3/8 inch holes along the top edge to plug weld them to the top piece. I cut the grooves to line up with the adjustment knobs. Sanded piece with a flap wheel then two coats of Rust-oleum.
2. Choked and pulled the starter cord. Engine turned over but cord didn't retract.
3. pulled engine cover off and sprayed WD-40 on end of snout. Balls freed up. Replaced the cover and pulled cord twice and the engine started. I let it run for 10 minutes.
4. The discharge chute hand knobs were totally rusted solid. I used a zip disk to remove then drilled out the remaining threaded part and ran a tap to establish new the threads.
5 Ordered a pair of hand knobs. Made a pair of temporary pieces from 5/16 bolts with a 2 inch piece of 1/4 inch round rod welded on the head.
6. I changed the direction of the discharge chute so it was more parallel with the ground. I modified the top of the chute by cutting each side at 2 inch intervals so I could flatten the top.
I made new sides from a piece of old washing machine sheet metal, drilled 3/8 inch holes along the top edge to plug weld them to the top piece. I cut the grooves to line up with the adjustment knobs. Sanded piece with a flap wheel then two coats of Rust-oleum.
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flail blade broke. Replace other worn parts while equipment was torn down.
Pete - February 7, 2020
Tool Type
Chipper Shredder
Difficulty
Easy
Time
30-60 minutes
Tools Used
Socket set, Wrench Set, allen wrench set
1.Remove lower housing bolts.
2.Remove 2 front frame bolts and loosen 2 rear frame bolts.
3. Separate front shredder assy. housing from rear housing
4. Replace broken and worn parts on shredder hub
5. Reassemble unit.
2.Remove 2 front frame bolts and loosen 2 rear frame bolts.
3. Separate front shredder assy. housing from rear housing
4. Replace broken and worn parts on shredder hub
5. Reassemble unit.
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N/a
Gregory - July 30, 2016
Tool Type
Blower
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Parts Used
Turned hand knob into welded nut.
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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.
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