Walls are never perfectly straight and floors are rarely level. One Source fillers and panels are designed so the installer can make the final fit on site, cleanly and with matching material. Here is how the system works, straight from the 2026 catalog.
How do One Source doweled fillers work?
Crown, fillers and return panels are doweled. You receive the coordinating size specified on the order, with dowels on the end and dowel holes on the face. Cut the width you need for the face in the field, then rotate the remaining piece to line up the dowels with the holes and create a custom L return.
Which filler types are available?
| Code | Filler | How it attaches |
|---|---|---|
| BXDF | Box doweled filler | Two front faces edgebanded on all four sides, with dowel holes on the back for two full-depth finished end panels |
| LDF | L doweled filler | Front face edgebanded on all four sides, attaches one full-depth finished end panel |
| JDF | J doweled filler | One full-depth finished end panel plus one finished L return |
| UDF | U doweled filler | Two full-depth finished end panels |
Standard filler sizes are 7 7/8″ wide: base (BDF-L, BDF-R) at 30″, wall (WDF-L, WDF-R) from 30″ to 72″, and tall (TDF-L, TDF-R) from 72″ up to the maximum material height. All fillers are trimmed to fit.
What crown options are there?
- CF: 3″ flat crown
- CDF: 3″ to 6″ flat crown with L return
- SCDF: 6″ flat crown with a 3″ CF added to the face and an L return
- VDF: valance with full-depth L return
How much scribe do end panels allow?
All end panels are oversized to allow for scribe: 3/4″ on the back side. TEP, BEP and IBP panels also have 1/2″ on the bottom when the selected material allows. Other panel items include light rail (LTR, 3″ x 96″), toe kick (TK, 4 1/2″ x 96″) and full-depth finished bottom panels (FBOT, and FBOT_LTR with a light route).
Why are finished end panels required?
One Source uses mortise and tenon construction: components interlock and are joined with assembly screws. Screws are visible on the side of the box, so a finished panel is required on exposed ends. Plan an end panel anywhere a cabinet side will show. The 3/4″ finished end panels are field applied.
What are the most common filler mistakes?
- Forgetting end panels on exposed sides of islands and peninsulas.
- Ordering fillers too narrow to clear handles and appliance doors.
- Not leaving scribe room where a wall bows.
Questions on a takeoff? Our design team works with contractors and builders across Arizona and Colorado. Full codes are in the 2026 catalog PDF.
Frequently asked questions
Are One Source fillers trimmed to fit?
Yes. All One Source fillers are trimmed to fit in the field. They ship doweled, and the remainder can be rotated to create a matching L return.
How much scribe is on One Source end panels?
End panels are oversized 3/4″ on the back. TEP, BEP and IBP panels also have 1/2″ on the bottom when the material allows.
Do One Source cabinets need end panels?
Yes, on any exposed side. Assembly screws are visible on the box side, so a finished end panel is required to finish exposed ends.
What size are One Source fillers?
Standard doweled fillers are 7 7/8″ wide, in base (30″), wall (30″ to 72″) and tall (72″ to maximum material height) lengths.
Specifications and finish counts are from the One Source Cabinets 2026 Product Catalog (October 2026 revision).