Short answer: for a small touchscreen in a cramped machine-shop spot, order a one-piece 304 stainless custom enclosure about 8 x 6 x 4 in, with the door cut at the factory to your display's mounting drawing. The form-fitted look you are after comes from one box and one gasket — no adapter plate stacking 3 to 10 mm [0.12 to 0.4 in] of extra thickness and a second leak path in front of the glass. Work three numbers in order, cutout, depth and rating, and the rest of the order falls out of them; the HMI enclosures guide carries the fundamentals this piece moves past.
What size enclosure fits a 3 inch touchscreen with no wasted space?
An 8 x 6 in body does it for a typical small-panel unit: the cutout centred in the door leaves 50 mm [2 in] of border each side and 37 mm [1.5 in] top and bottom. That border carries the door gasket and keeps the face flat enough to seal, so treat 35 mm [1.4 in] as the smallest edge distance you accept on the layout. The arithmetic is two additions: 100 mm of cutout plus 2 x 50 mm of margin gives the 200 mm width, and 76 mm plus 2 x 37 mm gives the 150 mm height. When the panel also lands a power supply or a few terminal blocks, step the height to 8 x 8 in [200 x 200 mm] and a short 35 mm DIN strip below the display carries them, with the cables arriving from underneath.
How much depth does a panel mount touchscreen need behind it?
Plan on 95 mm [3.7 in] behind the closed door for a unit this size: 30 mm of display body, 20 mm of connector shells, and 45 mm [1.8 in] of cable bend, which a 4 in deep enclosure carries with about 5 mm to spare. The bend allowance is doing real work, not padding. Small control cable wants a radius of five to six times its outside diameter per the cable datasheet — about 30 mm [1.2 in] for a 6 mm [0.24 in] OD cord — and your fingers still need room to reach a locking connector. Drop the cables straight down from the connectors and take the bend below them, where the body is deepest. The same depth logic on larger panels sits in how shallow an HMI enclosure can be for an 8 in panel.
Where do the cutout dimensions come from?
From the mounting drawing of your exact display model: the number in the name is the screen diagonal, and on the common small-panel units that drawing calls for a rectangular cutout near 100 x 76 mm [3.94 x 3.0 in]. Download the dimensional PDF for the exact part number and revision, mark the cutout centre on your layout, and put a plus or minus 0.5 mm [0.02 in] tolerance on the callout.
The flange seals on its own gasket across about 10 mm [0.4 in] of flat contact all around, so the hole needs to be on position, not close to it. Lay the door out in the cutout designer, which checks hole spacing and exports the layout. If the display itself is still open, how to specify a small display enclosure walks that choice; for bare OLED modules, sizing a panel cutout for a bare OLED display is the matching piece.
What NEMA rating does a machine shop HMI need?
Type 12 on a dry wall or bench, Type 13 bolted to the machine where coolant mist and oil spray reach the box, and Type 4X in 304 stainless the moment a hose or coolant jet can hit the panel. NEMA 250 draws those same lines: Type 12 covers indoor dust and dripping liquids, Type 13 adds oil and coolant spray, and Type 4X adds hose-directed water with corrosion resistance.
| Where it mounts | What reaches it | Order |
|---|---|---|
| Back wall, bench, office side | Dust, occasional drips | Type 12 |
| On the machine, mist and spray zone | Oil mist, coolant spray | Type 13 |
| Near washdown or coolant jets | Hose-directed water | Type 4X, 304 stainless |
In US installs, NEC 110.28 and its Table 110.28 assign enclosure types to locations, and an IP code alone will not satisfy a spec written in types. Every type and IP code on this site is a manufacturer rating for the specified design — rated NEMA 4X / IP66 by the manufacturer, not UL listed — and NEMA itself tests nothing. What you mount through the cutout sets the ceiling, so read what NEMA rating a panel keeps after you cut it and mount devices before you promise the customer a number, and the NEMA enclosure types guide maps every type to its conditions.
Should the enclosure be stainless or powder-coated steel?
Take 304 stainless with a #4 brushed finish for anything your customer will look at every day; powder-coated carbon steel in RAL 7035 light grey does the same job on a back wall nobody photographs. A machine shop is easy duty for 304 — coolant, way oil and shop humidity leave the brushed face clean where paint chips and stains. Move to 316L only when chlorides show up: chlorinated cleaning chemistry, salt air through a dock door, a brine quench in the next bay. Aluminum saves weight when the box rides on a swinging arm, and at 8 x 6 x 4 in the stainless version still lifts with one hand.
Will a small touchscreen overheat in a sealed box this small?
At about 7 W inside — a small touchscreen draws around 6 W per its datasheet, and the 24 V supply ahead of it loses about 1 W — an 8 x 6 x 4 in stainless box runs roughly 14 C above shop air, so a 25 C shop puts the inside near 39 C.
The heat leaves through the walls, and stainless transfers about 3.7 W per square metre per kelvin. This box has 0.134 m² of surface, so 7 ÷ (3.7 × 0.134) = 14 K, and 25 C + 14 K = 39 C inside. Panel electronics are 40 C parts unless the datasheet says more, and small-display datasheets typically allow 50 or 60 C, so you are sitting comfortably.
Ambient moves the answer more than the load does. The same 7 W at 35 C behind a machine in summer puts the inside at 49 C, right at a 50 C rating, so step up to 10 x 8 x 4 in [250 x 200 mm footprint]: 0.196 m² of surface drops the rise to 10 K and the inside to 45 C. A sealed Type 12 or 13 box runs no fan and needs none at these watts.
How do I mount and ground it where space is tight?
Four M6 screws through the back into the machine frame, one M16 and one M12 gland in the bottom face 25 mm [1 in] apart, and a bonding lead from the display's ground terminal to the enclosure's ground stud — the spring clamps retain the display in its cutout, they do not ground it.
Display installation notes say the same outright: the clamps are retention, so land the chassis bond as a wire you can see. Size it from the overcurrent device ahead of it with NEC Table 250.122 — 14 AWG [2.5 mm²] covers a 15 A feed. On powder-coated steel, NEC 250.12 wants paint off the contact surfaces at that stud; bare stainless bites in with a toothed washer.
Match each gland to its cable. Gland datasheets list the sealing ranges, typically 6 to 10 mm [0.24 to 0.4 in] OD for M16 and 3 to 6.5 mm [0.12 to 0.26 in] for M12, and the two need 16.5 mm and 12.5 mm holes set 25 mm [1 in] apart. On a box this small the glands go straight into the bottom wall — a stainless enclosure gland plate earns its keep on bigger panels. Keep 50 mm [2 in] clear in front of the door, and where even that is gone, order a screw cover that comes off flat against the machine. Lock out the feed and prove it dead before you land the 24 V and comm cables.
What goes on the order?
Send material, size, type, door cutout and gland holes as one spec — the table below is the complete order for this example — and the finished box is delivered in 10 business days anywhere in the world, counted from your approval of the drawing.
| Line | What to write |
|---|---|
| Body | One-piece custom enclosure, 304 stainless, #4 brushed |
| Outside size | 8 x 6 x 4 in [200 x 150 x 100 mm] |
| Rating | Type 13 at the machine (Type 12 dry wall, Type 4X near washdown), manufacturer rated |
| Door cutout | 100 x 76 mm [3.94 x 3.0 in], ±0.5 mm, per the display's mounting drawing |
| Cable entry | Bottom face: one M16 in a 16.5 mm hole, one M12 in a 12.5 mm hole, 25 mm apart, 25 mm from the walls |
| Ground | M5 stud inside, 14 AWG bonding lead to the display |
Send the spec with the display's mounting PDF through custom enclosures; a drawing comes back to you before anything is cut, so set it beside the display PDF one last time. Orders are placed and paid through the checkout of Industrial Monitor Direct, who builds, ships and supports every order. If the machine can carry a 7 in face instead of the smaller display, the 7 in panel PC housing in 304 stainless comes with its display opening and IP65-type front seal already engineered, and HMI enclosures run from 7 in up to 23.8 in.
Enclosures in this article
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 7" HMI enclosure | 304 stainless | 7.43 x 9.96 x 3.7 in | IP65-type front seal with the display installed, manufacturer rated; not UL listed |
Questions
Can I use a standard catalog HMI enclosure for a small touchscreen?
Not from this catalog: the standard stainless HMI housings are built around IMD panel PCs from 7 in up, so a small third-party display goes the custom route. You set the outside size and the door cutout, the box is built from one piece, and it is delivered in 10 business days counted from your approval of the drawing.
How much cutout tolerance should the drawing call out?
Put plus or minus 0.5 mm [0.02 in] on the cutout and name the display drawing and its revision on the callout. The flange seals on its own gasket across about 10 mm [0.4 in] of flat, burr-free contact all around, and an oversize hole eats into that contact until the seal goes soft at the corners.
Will a display flange gasket seal on brushed stainless?
Yes. A #4 brushed face is flat enough for a flange gasket: the seal comes from flat contact and even clamping, not from a polished finish. Have the cutout deburred at the factory, because a raised burr under the flange is a classic leak path on field-cut holes.
What if the mounting spot is shallower than 4 in?
Swap the straight connectors for 90 degree versions. An elbow M12 projects about 12 mm instead of 20 mm, so 30 mm of display body plus 12 mm of elbow plus 45 mm of cable bend adds to 87 mm and fits a 90 mm [3.5 in] deep body. Keep the bend allowance; give up the spare millimetres instead.
Does the enclosure rating survive the display cutout?
The assembly is rated by its lowest-rated part. A Type 12 box with an IP65-front display counts as Type 12 overall: the face itself is protected by the display's own gasket, and everything around it by the enclosure. Claim the lower of the two on your drawing and the panel never promises more than it delivers.
