Watson Skin Grafting Knife, Modified Humby Pattern
Price range: $ 110.00 through $ 190.00
A Watson skin grafting knife is a hand knife for taking split thickness skin grafts, and it is the Humby pattern modified: same long replaceable blade, same thumb screws setting the gap that decides the graft thickness, with the front guard changed. Catalogues list it as the Watson dermatome and as the Watson modification of the Humby knife, and both names describe the same instrument. It is used where a Humby is used, in burn surgery, trauma and reconstruction, and like the Humby it needs no power, no cable and no suction line.
Key Features
- The modified Humby pattern, with the front guard changed
- Thumb screw at each end of the frame sets the graft thickness
- Takes the same single use blades as our Humby
- Handle is fully reusable and autoclavable
- Order it bare, with 5 blades or with 10 blades
- Works with no power supply of any kind
- Non glare satin finish on the frame
- Item code AA-50.02
What a Watson skin grafting knife is
A Watson skin grafting knife is a hand knife for split thickness skin grafts and it is a modification of the Humby. The frame carries a long replaceable blade with a guard running parallel to it, and a thumb screw at each end sets the gap between guard and edge. Skin passes under the guard, is lifted by that gap, and the blade takes a sheet of that thickness. The names Watson knife, Watson dermatome and Watson modification of the Humby knife all mean this instrument.
One thing we will not do on this page is describe our own front guard in detail. The trade literature says the Watson modification is about how the guard is mounted, and our own product data does not record it, so rather than repeat a specification we cannot stand behind we say what the instrument is and what it is for. If you need that detail before ordering, ask us and we will confirm it from the workshop.
Key design features
What “modified Humby” actually means
The Watson is not a different instrument from a Humby, it is a change to one part of it. The frame, the blade, the two thumb screws and the job are identical. What the modification addresses is the front guard and how the harvested sheet behaves against it on a long pull. That is the whole difference, and it is why every catalogue in the trade files the Watson under the Humby family rather than on its own.
The gap is still the thickness
As on the Humby, a screw at each end of the frame sets the distance between the guard and the edge, and that distance is the thickness of the sheet the blade lifts. Both screws must read the same, every time. A graft that comes away thick at one end and thin at the other is almost always two screws set differently, not a bad blade.
One blade for both knives
Our Watson and our Humby take the same single use blade, which is the practical argument for buying both from one place: one blade line in the stores instead of two. The blade is never resharpened. A dull graft blade does not cut shallower, it drags, and drag tears a sheet rather than shaving it.
Where the money goes
The same instrument from the catalogue houses runs between about 1,575 dollars and just over 2,000 dollars. Ours is 110 dollars. The steel is not the difference and we will not pretend it is. The difference is that this comes out of our own workshop and is sold direct, with no distributor layer and no catalogue margin on top of it.
What to tell us when you order one
This product carries one option on our site, how many blades come with it. Everything else worth settling before you order is here.
| What to tell us | Why it matters | If you do not know |
|---|---|---|
| Bare handle, or with blades | The handle is reusable; the blades are not | Handle with 10 blades is the usual starting order |
| Watson or Humby | The front guard is the only difference and it is the whole decision | Read the comparison table below, then ask us |
| How many handles | A burn list often runs two so one is always clean and set | One to try, then a quantity once the fit is confirmed |
| Screw feel | Some units want the screws free, others stiff enough to hold a setting through a case | We ship them free and even |
| Your own item number | We mark an OEM run to your catalogue rather than ours | Leave it blank and the run carries our code |
Where it is used
It is chosen for what it does to skin, a thin even sheet lifted off a flat donor site, which is why the list runs from burns to debridement.
| Where it is used | What the knife is doing there |
|---|---|
| Burn surgery | Taking split thickness sheets to cover a deep or extensive burn |
| Trauma and tissue loss | Resurfacing an area lost to injury or infection |
| Large facial and scalp defects | Harvesting a sheet big enough to cover in one piece |
| Chronic wound and ulcer cover | Grafting a clean bed that will not close on its own |
| Wound debridement | Shaving away dead tissue in thin, controlled passes |
| Teaching and field surgery | A graft knife that needs no supply at all |
What it is used on, and what it must not be used for
A graft knife is a shallow instrument. The second column is where people reach for it and should not.
| It is used on | It must not be used for |
|---|---|
| A flat, firm donor site such as thigh, buttock or upper arm | A full thickness graft, which is cut and closed, not shaved |
| Skin held taut by an assistant or a board | Loose skin that cannot be held flat |
| A single steady pull in one direction | Sawing back and forth, which scallops the edge |
| A blade fitted and checked before the case | A blade that has already cut once |
| Thin, even passes for debridement | Cutting down to fascia, a different operation |
How it compares with the other graft knives
Four hand patterns and one powered class. We make two of them and the blades for both.
| Pattern | What is different about it | Do we make it |
|---|---|---|
| Watson | The Humby with the front guard modified. This page | Yes |
| Humby | The original pattern, with a rolling front bar | Yes, on this site |
| Braithwaite | A Humby modified around faster blade changing | No |
| Cobbett | A later hand knife, longer, for larger single sheets | No |
| Powered dermatome | Electric or air driven, needs a supply and servicing | No |
| Spare blades | Single use, and the same blade fits our Watson and our Humby | Yes |
Materials and finish
Every Watson knife we make is cut from high quality medical grade stainless steel. The steel itself is made to a German specification. We do not publish a grade number, because the number on a certificate tells a surgeon nothing about whether the blade still seats without rock after two hundred autoclave cycles, and the answer to that is in the making rather than in the alloy.
The surfaces that matter are the blade seat and the guard. The seat must hold the blade without rock, because a blade that lifts takes a ragged sheet, and the guard must stay straight along its length or the gap is wrong at one end. Both are machined and then finished by hand. The frame is satin rather than mirror, so nothing reflects back under theater lights.
Caring for it
Take the blade off first and dispose of it as a sharp. Back both thumb screws fully off so the guard sits at its widest, because a gap screwed shut traps tissue against the blade seat, and the seat is the one surface that has to stay true.
Brush the seat, the guard and both screw threads, then ultrasonic in a neutral pH enzymatic detergent. Rinse in deionized water, dry fully, autoclave at 134 degrees Celsius with the screws open, and lubricate the threads after drying rather than before. Before the next case set both screws to the same mark and sight along the guard against the seat. An uneven gap means the instrument needs attention, and we replace it inside the three years.
Ordering and wholesale
Every Watson skin grafting knife we sell is made in our own workshop and sold direct, which is why the price sits where it does against the catalogue houses. Order one for a single tray, or in quantity for a hospital list or a distributor line. We do OEM work under your own brand and your own item numbers, and we will hold a run to your pattern rather than ours if you send us a sample. Stock items ship from our own workshop. Backorder items take 10 to 12 working days to make. Every instrument carries a three year replacement warranty against manufacturing defects. Production is controlled under an ISO 13485 quality management system.
Frequently asked questions
What are the differences between the Humby knife and the Watson knife for skin grafting?
They are the same instrument with one part changed. Both have a long replaceable blade, both set graft thickness with a thumb screw at each end, and both do the same job in the same operations. The modification is to the front guard and how the harvested sheet behaves against it during a long pull, which is why the Watson is always described as a modification of the Humby rather than as a separate design. We make both, and the same spare blade fits either.
What type of knife is used for skin grafting?
Either a hand knife or a powered dermatome. The hand knives are the Humby and its modifications, which includes this Watson, plus the Braithwaite and the Cobbett. All of them work the same way: a long blade with an adjustable guard in front of it, set to the thickness you want. A powered dermatome does the same job with a motor and needs a supply behind it. We make the hand knives.
What are the different types of grafting knives?
The Humby is the original. The Watson changes the front guard. The Braithwaite is modified around faster blade changes, and the Cobbett is longer, for taking bigger single sheets. Below the hand knives sit the small graft blades that fit an ordinary number 3 scalpel handle, used for very small donor sites. We stock the Humby, the Watson and the blades for them.
What is the best knife for grafting?
The one your unit already trains on, which is a real answer rather than a dodge. A graft knife is used by feel over a long pull, and a surgeon who knows one pattern will take a cleaner sheet with it than with a pattern that looks better on paper. If there is no existing preference, the Watson and the Humby are both reasonable first knives and they share blades, so owning one does not lock out the other.
Does the Watson knife need power or a special supply?
No. It needs a flat donor site, a hand or a board keeping the skin taut, and a steady pull. There is no motor, no cable, no air line and no suction. That is why hand knives stay on burn trays in units that also own a powered dermatome, and why they are still the instrument in field surgery and in teaching.
Related products and categories
The Humby skin graft knife is the original pattern this one modifies, and the spare blade for the Humby and the Watson fits both of them. For a plain blade handle rather than a graft knife, the number 3 scalpel handle is the standard small pattern. The whole family is listed in scalpel handles and skin grafting tools, and the wider reconstructive range sits under breast surgery instruments.
| Weight | 0.2 kg |
|---|---|
| More Option | Handle With 10 Blades, Handle With 5 Blades, Only Skin Grafting Handle |
Shipping & Delivery Policy
Processing Time: In-stock items are dispatched within 24-48 hours. For custom or out-of-stock items, production time is approximately 10-15 days.
Global Delivery Estimates
We partner with world-class couriers (DHL, FedEx) to ensure fast, tracked delivery.
- USA & Canada: 3-5 Business Days
- Europe & UK: 4-6 Business Days
- Rest of World: 5-7 Business Days
*We offer Air Cargo and Sea Freight options for bulk wholesale orders.
Customs & Duties
International buyers are responsible for any customs duties or taxes imposed by their country. Adas Instruments is not responsible for delays caused by customs clearance.
Lost Packages & Insurance
If your package is lost in transit, please contact us immediately. We offer full support and replacements for confirmed lost shipments. Note: You must report non-delivery within 3 weeks to be eligible for an insurance claim.
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