Bone Saw Machine: 15 m/s, 57 Newtons, and Seven Model Names

The parameter block is empty, and the description is a template

The product page publishes zero parameters. The description, all 800 characters of it, reads in full:

“Product Description / Butchery Pig Frozen Bone Saw Electric Meat Machine … If you make the order in our store, the each model real picture as follows: Packing&Shipping / Company Introduction / Company introduction. Hengshui Mengshang Trading Co., Ltd. is a main professional supplier in Product Machine, CNC Carbide inserts, Turning tools and Milling tools…”

That is a cutting-tool company's boilerplate. It says nothing about a bone saw: no blade, no table, no throat, no cutting height, no speed, no weight. A block of identical text appears on the hydrogen generator and the nail-gel filler listed in this same catalogue, which tells you how much attention went into it.

A sibling listing for what appears to be the same machine goes further. Item 181, in the same family with three of the same photographs, describes itself as “Shenzhen onetouch trading company … a wholesale company that manufactures good & high quality knitting wear and woven wear, starting from 2006 … current styles and fabrics.” A meat saw introduced by a garment wholesaler.

The specifications are inside the photographs

The eight images carry six specification panels. Reading them is the only way to learn anything about this machine, and they do not agree with each other or with the model table on the sibling listing.

A fifth model appears in the sibling listing's parameter table but on no panel: SJY-F280A, 1.8 kW, 62 × 50.5 × 103 cm, 60 kg. Counting the two sources, this family carries seven designations — W120BC, W120A, F120A, F210A, F250A, F280A and W250BE — and no single page lists them all.

Every model runs at the same band speed

Fifteen metres per second, on all six panels. That is the single most consistent number in the listing, and it is worth understanding what it does and does not tell you.

Band speed is what turns motor power into cutting force. For a blade moving at velocity v driven by power P, the force available at the cutting edge is F = P / v. With v fixed at 15 m/s across the range, power converts to force one for one:

That is the whole difference between the classes, and it is a modest one: the 1.5 kW machine has 1.76 times the cutting force of the 0.85 kW machine, not twice, and the 1.8 kW has 2.1 times. Everything else on the panels — the stainless tag, the cutting height, the pulley — is a different question.

The practical consequence is that 57 N is a small number. An operator leaning on the sliding carriage can supply more than that by hand. On the 0.85 kW models the motor, not the operator, becomes the limit, and the symptom is a stalled blade in a frozen cut rather than a slow one.

What 15 m/s means in revolutions, and the pulley that cannot exist

Wheel speed follows from band speed and pulley diameter: revolutions per second equals 15 divided by the circumference.

The F250A panel lists a pulley diameter of 1,710 mm. The machine it is printed on is 1,020 mm tall. The pulley would be 690 mm wider than the machine is tall, and its circumference alone would be 5.37 metres. It cannot exist, and it is a typographical error for 165 mm, which is what the identical W250BE panel states.

Two things follow. First, the 0.85 kW class runs its wheel at 2,238 rpm and the 1.5 kW class at 1,736 rpm; lower speed with more power is the right direction for harder product, and it is the reason the bigger machine costs more than a bigger motor. Second, when one field on a printed panel is impossible, the rest of that panel deserves checking rather than trust.

Torque at the wheel, T = P / ω, gives 3.63 N·m on the 0.85 kW/128 mm combination against 8.25 N·m on the 1.5 kW/165 mm one — a factor of 2.3, which is the real measure of how much harder the larger saw can push.

Power supply: single phase only, and close to a small breaker

Every panel states 220 V. There is no three-phase option anywhere in the family, so the saw needs a single-phase circuit regardless of which model you choose.

Assuming a power factor of 0.80 and motor efficiency of 0.85, the 1.5 kW models sit exactly at the rating of a 10 A circuit and the 1.8 kW model exceeds it. In a kitchen wired with 10 A circuits, the larger saws need their own 16 A supply, and the 1.8 kW model should not share a circuit with anything that cycles.

Starting current is not published. A direct-on-line single-phase motor of this size draws several times its running current for a fraction of a second, which matters if the circuit already carries refrigeration.

Cutting height is the number that decides frozen from fresh

Three different cutting heights appear across six panels:

The 40 mm between the 200 mm and the 260 mm class is the difference between a saw that cuts portions and one that breaks down frozen blocks. It is also the only published dimension that changes between the two 1.5 kW machines: F210A gives 220 mm and W250BE gives 260 mm for the same money in power, pulley and footprint.

Note what is not published: the throat, meaning the distance from the blade to the column, which sets the largest radius of workpiece that will pass. The overall dimensions do not give it. A 620 × 505 mm footprint tells you the machine's outline, not the opening you can push meat through.

The model digits do not match any published dimension

It is natural to read 120, 210 and 250 as millimetres of something. They do not line up with the cutting height:

If the digits were the cutting height, the 120 class would cut 120 mm, not 200 mm. If they were the throat, the 120 class would leave 120 mm from blade to column, which the panel does not state either. The pattern for 210 and 250 — digits plus ten — is suggestive, but the 120 breaks it by 80 mm, so the scheme is not consistent and the page never defines it.

Two pairs of panels are worse than uninformative, they are indistinguishable:

If W and F mean two different body materials, the panels should not both claim full stainless steel. If they mean something else, the listing does not say. In either case you cannot choose between them from this page, and the price difference between two designations that look identical is exactly the sort of thing a buyer should ask about.

The blade is the recurring cost, and it is not specified

Every number above is a purchase decision you make once. The blade is the decision you make every few weeks, and the listing publishes none of it: no blade length, no width, no thickness, no tooth pitch, no tooth material.

For a band saw this is the practical trap. Blade length is fixed by the wheel diameter and the frame geometry, and a length that only the seller stocks means every replacement comes from the same seller at whatever price they set. Three things to establish before ordering:

• Blade length in millimetres, so you can price it against commodity suppliers
• Blade width and thickness, which set the minimum radius the blade can turn on these wheels
• Tooth pitch options, because frozen bone and fresh meat want different pitches, and pitch is the one variable left to you when the band speed is fixed at 15 m/s

The listing advertises both frozen and fresh product in the same title, on the same machine, at the same speed. Since those two duties want different blades, the blade is where the difference has to be made, and no blade is specified.

For a food machine, the hygiene declarations are missing

A saw that contacts raw meat is not an ordinary machine purchase. The things a buyer needs and this page does not give:

The panels do show a sliding pusher and carriage at the left of the table, which keeps hands away from the blade, and an enclosed upper wheel housing. Those are real and worth noting. What is absent is documentation rather than hardware.

What 30 to 60 kilograms means for the floor and the freight

The sibling table gives net weights: 30 kg for the 120 class, 53 to 54 kg for the 210 and 250 classes, 60 kg for the 280. Those are net weights, not shipping weights, and no crate dimension appears anywhere.

Two details worth flagging. The F210A to F250A step adds 10 mm of cutting height and 1 kg of weight, while the F280A adds another 10 mm of height and 6 kg — the last step is six times heavier for the same increment, which suggests a different frame or motor rather than a scaled opening. And the 1,020 mm tall models are floor-standing while the 720 mm ones need a table at working height, so the installation differs even though the titles do not.

For freight you need gross weight and crate dimensions, neither of which exists here. At 60 kg net a single crate is likely to move as general cargo rather than parcel, and the rate depends entirely on the carton, not the machine.

Choose by force and height, not by model number

Strip away the designations and there are three real choices:

The last row is the problem. The model most suited to frozen production is the one with no published speed, no published cutting height and no published pulley. Its power and weight are known from a table; nothing about its cut is.

For everything else, the decision reduces to two numbers you now have: force at the blade, which is power divided by 15 m/s, and cutting height, which is 200, 220 or 260 mm. Buy on those and the model letters stop mattering.

What to put in the request for quotation

Question 1 is the one that unblocks the rest. Until the seller names a single model, every other answer applies to a family of seven.

The honest summary

There is a real machine behind this page. The panels show an enclosed upper wheel housing, a sliding pusher carriage, an emergency stop on the larger models, and a body described as full stainless. The dimensional data in the sibling table is coherent, and the weights are consistent with the sizes.

What is missing is the product identity and the four numbers that decide whether it works for you: blade length, throat depth, cutting height for the model you actually get, and the tooth pitch you can buy. Against that, the published force figures — 57, 100 and 120 newtons — are genuinely useful, because they come from two numbers the panels do state plainly, power and band speed, and they are enough to tell you which class you need.

One printed pulley size on a 1,020 mm machine reads 1,710 mm. Treat that as a reminder to confirm every field rather than a reason to walk away.