Products for bench top machinists | LittleMachineShop.com

Insert, TPMB-321 Carbide

Insert, TPMB-321 Carbide - Main image
$8.42 $12.95 In stock

TPMB-321 carbide is a 60° triangle with a 11° relief.

The center hole is a 70°-90° single countersink, and there is no chip breaker.

It has an inscribed circle (IC) of 0.375" (3/8"), a thickness of 0.125" (1/8"), and a corner (nose) radius of 0.0156" (1/64").

The insert is designated TPMB321 (ANSI) or TPMB160304 (ISO).

Inserts are sold individually—no need to buy a pack of 10 inserts.

*NOTE: Make sure you get the correct inserts and retaining screws for your indexable turning tools. Our chart of indexable inserts shows which inserts and which screw to use with each of our indexable tools.

Before you pay

Check the method and total at checkout.

When it ships

Allow for processing time as well as the journey to you.

Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

View policy
If you need a refund

Keep your order number and contact the store to start.

Please contact us for the refund processing timeframe before returning an item.

View policy
Delivery costs

Review the cost for your destination and chosen service.

Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

View policy
Returning an item

Check the return conditions before sending anything back.

United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

View policy

Customer Reviews (4.8 / 5 · 5 reviews)

Zoe ★★★★★

The single countersink on these 60° triangles sits perfectly flush in my tool holder. The 11° relief gives a clean, chatter-free finish on aluminum and mild steel.

Richard ★★★★★

Needed a new set for my lathe and these 60° triangles with the 11° relief cut through stock clean as can be. The single countersink hole made setup a breeze too.

Alexander C. ★★★★★

Got these to replace some worn out inserts on a small boring bar, and the 60° triangle with no chip breaker works great for finishing passes. The 3/8" inscribed circle seats perfectly in my holder with no play. Cut aluminum and mild steel so far with nice surface finishes.