{"product_id":"castair-1-5-hp-single-stage-1-cylinder-air-compressor-bare-pump-with-10-1a-flywheel-od-8-oz-oil-capacity-pk30","title":"Castair 1.5 HP Single Stage 1 Cylinder Air Compressor Bare Pump with 10-1A Flywheel OD 8 oz. Oil Capacity PK30","description":"\u003cp\u003eThe Castair PK30 is a 1.5 HP single-stage, single-cylinder bare pump with a 10\" (1A-series) flywheel and 8 oz. oil capacity. Like the PK20, this is the pump assembly only — no motor, no tank. The key difference from the PK20 is the larger 10\" flywheel, which affects the drive ratio and adds rotational mass for smoother compression strokes. The PK30 is used when the motor pulley and belt drive configuration requires a larger flywheel OD to achieve the correct pump RPM from the available motor speed.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote: Cast Air did not provide a dedicated manufacturer product page for this pump.\u003c\/strong\u003e Specifications are drawn from the product listing. Call us to confirm CFM output, max PSI rating, and motor\/belt compatibility for your specific application before ordering.\u003c\/p\u003e\n\n\u003ch2\u003ePK30 vs. PK20 — Which Do You Need?\u003c\/h2\u003e\n\u003cp\u003eBoth the PK20 and PK30 are 1.5 HP single-cylinder single-stage pumps with the same oil capacity and identical HP rating. The difference is flywheel size: 7.5\" on the PK20, 10\" on the PK30. The flywheel OD affects your drive ratio and the required motor pulley size. When replacing an existing pump, you need to match the flywheel OD of the original, not just the HP rating — otherwise the motor pulley will produce the wrong pump RPM. If your original pump had a 10\" flywheel, the PK30 is the correct replacement. If it had a 7.5\" flywheel, order the PK20.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Flywheel Size Matters\u003c\/h3\u003e\n\u003cp\u003eThe flywheel on a piston compressor pump serves two purposes: it provides the groove surface for the belt drive (setting the driven side of the ratio), and it adds rotational inertia to smooth out the compression stroke. A 10\" flywheel on the PK30 paired with a motor pulley of approximately 5.1-6.2\" OD (at 1,750 RPM motor speed) achieves the target pump RPM of 900-1,100. If the same motor and motor pulley were connected to the PK20's 7.5\" flywheel, the pump would spin much faster — outside its rated RPM range. Match the flywheel to the drive system, not just the horsepower.\u003c\/p\u003e\n\n\u003ch3\u003ePump Specification Details\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e PK30\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHP Rating:\u003c\/strong\u003e 1.5 HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStage:\u003c\/strong\u003e Single stage\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinders:\u003c\/strong\u003e 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlywheel OD:\u003c\/strong\u003e 10\" (1A-series flywheel)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOil Capacity:\u003c\/strong\u003e 8 oz.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrive:\u003c\/strong\u003e Belt drive\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e $241.01\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eOil-Lubricated Pump Maintenance\u003c\/h2\u003e\n\u003cp\u003eThe PK30 is oil-lubricated with an 8 oz. crankcase. Proper oil maintenance is critical to pump longevity:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eCheck oil level before each use — low oil is the most common cause of premature pump failure\u003c\/li\u003e\n\u003cli\u003eChange oil at Cast Air's specified intervals (confirm interval in the pump documentation)\u003c\/li\u003e\n\u003cli\u003eUse compressor pump oil — not motor oil, not synthetic automotive oil unless specifically approved by Cast Air\u003c\/li\u003e\n\u003cli\u003eWatch the oil sight glass or dipstick; overfilling causes oil carry-over into the tank and air lines\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhen Does a Shop Need the PK30?\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eOriginal 1.5 HP single-cylinder Cast Air pump with 10\" flywheel has failed\u003c\/li\u003e\n\u003cli\u003eMotor and tank are in serviceable condition and pump is the only failed component\u003c\/li\u003e\n\u003cli\u003eBuilding a custom 1.5 HP compressor where a 10\" flywheel drive configuration is required\u003c\/li\u003e\n\u003cli\u003eLight to medium shop demand — inflation, blow guns, intermittent pneumatic nail guns or light impact use\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eCast Air Bare Pump Comparison\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePK20 — 1.5 HP, 1-cylinder, 7.5\" flywheel, 8 oz. — $194.81\u003c\/strong\u003e — same HP as PK30, smaller flywheel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePK30 — 1.5 HP, 1-cylinder, 10\" flywheel, 8 oz. — $241.01\u003c\/strong\u003e (this unit) — same HP, larger flywheel for different drive ratio\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePK50 — 2 HP, V-2 cylinder, 10\" flywheel, 16 oz. — $371.91\u003c\/strong\u003e — step up in CFM output and HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePK60 — 3.5 HP, V-2 cylinder, 10\" flywheel, 32 oz. — $432.74\u003c\/strong\u003e — heavy shop applications\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e PK30\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air (Castair)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHP:\u003c\/strong\u003e 1.5\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStage:\u003c\/strong\u003e Single stage\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinders:\u003c\/strong\u003e 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlywheel OD:\u003c\/strong\u003e 10\" (1A-series)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOil Capacity:\u003c\/strong\u003e 8 oz.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrive Type:\u003c\/strong\u003e Belt drive (flywheel included, belt not included)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e $241.01\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCFM\/PSI:\u003c\/strong\u003e Not confirmed in listing — call for current performance specs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Data:\u003c\/strong\u003e Product page not available — specifications from product listing data\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat Is Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1x Castair PK30 bare pump with 10\" flywheel\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMotor, motor pulley, belt, tank, pressure switch, safety valve, and all connecting hardware are not included. This is the pump assembly only.\u003c\/p\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eWhen replacing a pump, matching the flywheel OD to the existing drive configuration is as important as matching the HP. We have been working with Cast Air pump assemblies since 2016 and can help you confirm whether the PK30 (10\" flywheel) or PK20 (7.5\" flywheel) is the correct replacement for your specific unit. Free shipping, free tech support, full manufacturer warranty.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCast Air specialist\u003c\/strong\u003e since 2016\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree shipping\u003c\/strong\u003e on all orders\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree tech support\u003c\/strong\u003e — we confirm the correct flywheel and drive configuration\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFull manufacturer warranty\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHonest guidance\u003c\/strong\u003e — we will tell you if PK20 is the right call instead\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for quick answers and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342574575829,"sku":"PK30","price":444.46,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/CastAirTwoStageAirCompressorPump_8b74b553-b53b-4346-813c-3c9005c955ac.png?v=1772652789","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-1-5-hp-single-stage-1-cylinder-air-compressor-bare-pump-with-10-1a-flywheel-od-8-oz-oil-capacity-pk30","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}