A: Hi Scott, Our #8 FIN/TRIM screw has a head OD of 0.197" for more information see the engineer drawing found here: https://www.grkfasteners.com/getattachment/cbe1684f-0b30-4486-93f8-84d28879311a/Sales-Support-TRIM-RT or reach out to our customer service team at at (877) 489-2726 or email us at CS@itwbrands.com
A: Hi Bill, we recommend using the GRK RT Composite screws for any composite fastenings. The reverse thread on that product was designed to mitigate the material around the head dimpling. If you have additional questions please contact our customer service team at (877) 489-2726 or email us at CS@itwbrands.com.
A: I have used these trim head screws in MDF and never needed to predrill nor countersink for the heads. There was no "bubble up" issue where the head penetrated the MDF to contend with either. Great holding strength too.
A: YES, absolutely. Will countersink into hardwood as well.
A: Yes, they are designed to countersink and do so easily.
A: They should. You can always use a countersink bit designed for that purpose.
A: I would think so, depending on wood thickness & material.
A: Yes, would consider using wood glue on joists to fight against gravity teamed with the screws
|Brand||GRK Fasteners||GRK Fasteners||GRK Fasteners||GRK Fasteners|
|Name||#8 x 1-1/4 in. Star Drive Trim-Head Finish Screw (100-Pack)||#8 x 2 in. Star Drive Trim-Head White Trim Screw (100-Pack)||#8 x 2-1/2 in. Star Drive Trim-Head White RT Composite Finish Screw (100-Pack)||#10 x 2-1/2 in. Star Drive Bugle Head R4 Multi-Purpose Wood Screw (80-Pack)|
|Screw Length||1-1/4 in||2 in||2-1/2 in||2-1/2 in|
|Head Style||Trim||Trim||Trim||Bugle Head|
|Interior/Exterior||Exterior, Interior||Exterior, Interior||Exterior, Interior||Exterior, Interior|
|View Product||View Product||View Product||View Product|