Every pipe threader gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Threaders are grouped by type, machine and hand-held, and weight has its own scale for each.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per inch of the largest pipe it threads | 30% |
| Capacity | largest pipe it threads | 20% |
| Dies | how much of its range the dies in the box cover | 15% |
| Weight | weight as sold | 10% |
| Warranty | length of the warranty | 25% |
Where the numbers come from
Pipe range, dies, speed, weight and warranty come from the maker’s spec sheet, manual or product page, or from the seller’s listing when the maker doesn’t publish them. Prices are checked at Amazon and the lowest price at a store the page links to is used.
The factors
Value is the current price divided by the largest nominal pipe size the maker rates it for, in inches, on a log scale, so halving the price per inch always counts the same. $3,000 per inch scores zero and $100 per inch full marks, the same scale for machines and hand-held drives.
Capacity is the largest pipe it threads: 1 in scores zero and 4 in full marks.
Dies is the share of the machine’s rated pipe range covered by the dies or die heads that come in the box. A kit with dies up to its largest rated size scores full marks; a drive sold without dies scores zero.
Weight is the weight as sold. For machines, 400 lb scores zero and 100 lb full marks; for hand-held drives, 40 lb and 10 lb. Where only a shipping weight is published, it is used and the product page says so.
Warranty is the length of the warranty: 1 year scores zero and 5 years or longer (including lifetime) full marks.
What isn’t scored
Motor wattage and spindle speed are listed but not scored: universal motors and induction motors, and rated input against output power, aren’t comparable between makers, and the generic 2300 W drives claim far more watts than a RIDGID drive that outthreads them. Whether a cutter, reamer, oil system and stand are in the box is shown on the product page. Independent test results are shown when there are any.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. The exception is warranty: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as the shortest warranty on the scale, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.