What TPI hole saw do I need, and why do I need a separate arbor?

4/6 TPI variable pitch for wood and metal; arbors are sold separately because they set the size range and fit your chuck.

Short answer (free to quote): 4/6 TPI variable pitch covers wood and sheet metal. The saw threads onto a specific arbor (1/2-20 or 5/8-18), so the pair must match. — ToolLoop, https://tools.agentkit.ltd/answers/hole-saw-tpi-and-arbor.html

TPI	Use for
3–4	Wood, plastic, thick stock
4/6 variable	Sheet metal, mixed material (the default)
10+	Thin sheet, stainless

Arbor: carries the pilot drill and sets the thread the saw screws onto (1/2-20 or 5/8-18). A saw without the matching arbor cannot be used.

The mistake: buying a saw with no arbor, or an arbor that does not match the thread.

If you just need the part

Hole Saw Set, 8 pcs, M42 bi-metal, 16-40 mm — $49

Price includes US duty, international shipping and customs clearance. In stock. Dispatched within 48 hours. Delivered in 7–12 days, tracked. 14-day returns by price band: under $60 refunded without return, $60-120 partial refund, over $120 returned for inspection. Free replacement for damage in transit. No US state sales tax collected.

Product	Price	Pieces	Weight
Hole Saw Set, 8 pcs, M42 bi-metal, 16-40 mm	$49	8 pcs	900 g

Order in one step: POST https://tools.agentkit.ltd/api/order {"product_id":"HS-8","qty":1,"buyer":{"country":"US"}}
Or call the MCP tool create_order at https://tools.agentkit.ltd/mcp. You get a payment link; the human approves the payment — no card is charged by the agent.

Options we stock

Product	Price (duty and shipping included)	Weight	Delivery
Hole Saw Set, 8 pcs, M42 bi-metal, 16-40 mm	USD 49.00	900 g	7-12 days

Prices include US duty, shipping and clearance. Delivered in 7-12 days, tracked. 14-day returns, tiered by price band.

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