DeWalt DCCS620 Chain: Size, Part Number and Fitting

One bar, one chain

The DCCS620 ships with a 12” bar, and DeWalt’s manual lists no other bar or chain for it. The replacement chain is DWRC1200 (service part 90586162). The replacement bar is service part N507300 (manual pp. 13 and 17).

The manual gives part numbers but not the chain size. The size comes from two other official sources. DeWalt’s DWZCSB12 12” bar page names the DCCS620 and calls for 3/8” low-profile, .043” gauge chain. Oregon’s 90PX045G fits the DCCS620B and DCCS620P1, and that chain has 45 drive links. So any replacement must be 3/8” LP, .043”, 45 drive links.

If you have the old chain, count the drive links before you order. These are the teeth that ride inside the bar groove.

DCCS620 or DCCS621?

DeWalt gives the two saws different replacement parts. The DCCS621 manual lists chain DWO1DT612 and bar DWZCSB12. The DCCS620 manual lists DWRC1200 and N507300. Check the model number on your saw before you order a DeWalt part. Oregon lists its 90PX045G for both saws.

Changing the chain

The DCCS620 has tool-free tensioning. A locking knob holds the sprocket cover, and a separate knob sets the tension (manual pp. 12–13):

1. Take the battery out and wear gloves. Set the saw on a flat, firm surface.
2. Flip up the locking lever and turn the bar adjust locking knob counterclockwise. Take off the sprocket cover.
3. Lift the old chain out of the bar groove.
4. Fit the new chain in the bar groove. Match the arrow on the chain to the graphic on the sprocket cover so the teeth face the right way.
5. Put the chain around the sprocket. Line up the slot in the bar with the tensioning pin and the bolt on the saw.
6. Hold the bar still and refit the cover so its bolt hole lines up with the bolt. Turn the locking knob clockwise until it clicks, then back it off one full turn.
7. Turn the chain tensioning knob clockwise until the chain is snug on the bar.
8. Tighten the locking knob until you hear three clicks. DeWalt says no further tightening is needed.

Setting tension

With the battery out and the saw on a flat surface, pull the chain 1/8” (3 mm) away from the bar with light force from your finger and thumb. It should snap back. There should be no sag between the chain and the underside of the bar (manual p. 12).

To adjust, flip up the tab and loosen the locking knob one full turn. Turn the tensioning knob clockwise until the tension is right, then retighten the locking knob. Don’t over-tighten the chain; DeWalt says that wears out the bar and chain faster. A new chain stretches a little, so check it often during the first 2 hours of use (manual p. 13).

Oil

The saw oils the bar and chain on its own. Refill when the oil level window shows less than a quarter full. Use bar and chain oil. Non-detergent SAE30 motor oil is fine as a stopgap. DeWalt recommends vegetable-based bar oil when pruning trees, and says never to use waste oil or very thick oil. Empty the tank when you finish cutting (manual p. 13).

When a new chain doesn’t fix it

DeWalt’s manual gives no wear limits for the sprocket or bar. What it does give is a care routine for the bar and chain:

• Every few hours of use: take off the sprocket cover, bar and chain. Clean them with a soft brush and make sure the oil hole on the bar is clear (p. 17).
• When you fit a sharp chain: DeWalt says it is good practice to flip the bar over (p. 17).
• Check the oil: stop now and then and look at the oil window to make sure the bar and chain are getting oil (p. 13).

If the chain still cuts poorly after this, DeWalt says repairs and adjustment should be done by an authorized DeWalt service center, which also stocks the N507300 bar (pp. 13 and 16–17).

Sharpening

DeWalt calls for a 4.5 mm round file in a file holder or filing guide (manual p. 17):

• Lay the holder flat on the cutter’s top plate and depth gauge.
• Keep the 30° line on the guide parallel to the chain.
• File each cutter from the inside out. Do all the cutters on one side, then turn the saw around and do the other side.
• Keep all cutters the same length.
• Use a flat file to take the rakers down to about .025” (.635 mm) below the cutter tips.

DeWalt recommends sharpening a chain no more than four times. Each sharpening reduces its low-kickback qualities. After that, fit a new chain.