Quick answer: The headstock and tailstock Morse taper sizes must match the accessory shank; a pen mandrel labeled MT2 does not fit an MT1 socket.
The simple answer
The WEN LA3421 is a documented MT1 machine. The WEN LA3424, RIKON 70-105 and JET JWL-1015VS document MT2 tooling. Confirm the exact model revision and manual before ordering, especially for used equipment.
Headstock versus tailstock
A thread-on mandrel like PSI PKM-BL takes another route: it specifies a 1-inch by 8-TPI spindle thread rather than a Morse taper. A headstock’s thread should be checked separately from its internal taper. The existence of one does not establish the other.
What a 7 mm mandrel means
When a kit says “MT2 7 mm mandrel,” read both parts: MT2 is the machine interface; 7 mm is related to the pen system. One relates to the lathe, one relates to the blank and fittings.
How to verify the fit
If you inherit unlabeled accessories, do not force a suspect taper into the spindle or improvise spacers. Consult the manufacturer or a competent woodturning specialist. Incorrect seating can compromise workholding and is more consequential than simply wasting money.
A starter selection
The most reliable way to avoid confusion is a short parts sheet attached to your workbench. For every new pen kit, note its tube length, drill size and bushing part number before you start cutting.
Compatibility case study: two apparently similar shopping carts
The tailstock matters too. PSI PKMSTS1 and PKMSTS2 share a purpose but have distinct MT1 and MT2 mounting shanks. Buy the correct one before testing an unsupported adapter.
Which specification should you screenshot?
Capture the exact lathe nameplate and the manual’s headstock/tailstock taper specifications. Then save the pen kit’s instructions showing drill size, tube dimensions, bushing model and press sequence. A seller’s phrase “works with mini lathes” is not a substitute for these two documents.
Sources and further verification
Source links are included to help you confirm equipment specifications, accessories and recommended safety practices. Specifications may change with product revisions.
- wenproducts.com — products wen la3421 3 2 amp 8 inch by 13 inch variable speed mini benchtop wood lathe
- wenproducts.com — products wen la3424 4 5 amp 12 inch by 18 inch 5 speed benchtop wood lathe
- rikontools.com — product model 70 105 10 x 18 mini lathe
- jettools.com — jwl 1015vs 10 x 15 variable speed wood lathe
- pennstateind.com — store PKM BL.html
- pennstateind.com — store PKMS2SET.html