Tornado Screw Hex Head Cap 1/4-20 x 4-1/4″ Zinc Plated 17644

Four and a quarter inches is a long screw for a 1/4-20 thread, and that length is the specification rather than an approximation. Part number 17644 is the genuine OEM hex head cap screw at that size, zinc plated.

Compatible Models for the Screw Hex Head Cap 1/4-20 x 4-1/4″ Zinc Plated

This part is shared across a wide run of machines. On the Marathon 1200 family it is fitted to:

• Tornado 98168 12 Gallon Self Contained Carpet Extractor
• Tornado 98168 20″ Marathon 1200 Carpet Extractor (12 Gallon, 115V) — all series
• Tornado 98169 20″ Marathon 1200 Carpet Extractor (12 Gallon, 230V)
• Fits many other machines — call 763-535-0770 and we will confirm fitment for your machine.

A long thin fastener behaves differently from a short one. It stretches measurably as it is tightened, which is part of how it holds — but it also bends far more easily during handling, and a screw with even a slight bow in it will bind going in and will never clamp evenly once seated. Roll a used one on a flat surface before refitting: a bent screw is obvious the moment it wobbles.

Because it passes through several parts, it is also the fastener most likely to be cross-threaded. It enters its thread a long way from where your hands are, so the feel is poor and it is easy to start it crooked. Turn it backwards until you feel the thread drop into its start, then turn it forwards — that one habit prevents most stripped threads on long fasteners.

Do not substitute a shorter screw with a stack of washers to take up the difference. The washers compress, the effective grip length changes with torque, and every interface is a place for the assembly to shift. If the correct screw is not to hand, wait for it.

Zinc plating is a thin corrosion barrier. A screw whose plating has been scraped through by a poorly fitting socket, or that shows rust, will corrode into its thread — and at 4-1/4 inches there is a lot of thread to seize.

Fit with clean threads, started by hand along the full length, and tightened to a firm figure. A long 1/4-20 will strip its female thread before it warns you.

Browse every assembly for this machine on the Tornado 98168 Marathon 1200 parts hub, and see the manufacturer’s range at tornadovac.com.

Frequently Asked Questions

What machines does the screw 17644 fit?

It is fitted to the Tornado 98168 12 Gallon Self Contained carpet extractor and the 98168 20″ Marathon 1200 in all series, and it is shared across many other machines. Call 763-535-0770 with your model and serial number and we will confirm fitment before you order.

Why does a long screw need extra care going in?

Because it enters its thread a long way from your hands, so the feel is poor and it is easy to start crooked. Turn it backwards until you feel the thread drop into its start and then turn forwards — that single habit prevents most stripped threads on long fasteners.

Can I use a shorter screw with washers to make up the length?

No. Washers compress, the effective grip length changes with torque, and every interface is a place for the assembly to shift. Roll a used screw on a flat surface before refitting too — a long thin fastener bends easily in handling and a bowed one never clamps evenly.

How do I order the Screw Hex Head Cap 1/4-20 x 4-1/4″ Zinc Plated (part# 17644) or get help?

You can add the Screw Hex Head Cap 1/4-20 x 4-1/4″ Zinc Plated (part# 17644) directly to your cart on this page, or call us at 763-535-0770. Our staff at 5415 West Broadway, Crystal, MN 55428 has been servicing Tornado equipment since 1956 and can help confirm the right part for your machine.

Questions? Call us at 763-535-0770 or visit us at 5415 West Broadway, Crystal, MN 55428.