Fixtures
Custom Drill Jigs and Trim Jigs, Machined to Print
A hardened bushing puts the hole where the print says, on a part that was never flat enough to lay out by hand.
A drill jig guides the drill through a hardened bushing so a hole lands in the right place on a part that cannot be laid out easily, such as a molded, cast or formed piece. A trim jig does the same for a router or trim cutter along an edge. The jig locates the part on its datums, holds it, and puts the bushing where the print says. Send the part model and print with the holes marked; a person quotes in 24-48 hours, standard lead time 4-6 weeks.
Updated September 2026
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Get a Quote in 24-48 Hours
Send us your files and we’ll quote it, usually within 24-48 hours.
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Commercial work only. We don’t quote firearms, DoD, ITAR, or EAR-controlled parts.
Jig, not fixture: the tool is guided, not just the part
Wikipedia’s Jig (tool) entry (en.wikipedia.org/wiki/Jig_(tool)) makes the distinction that matters here: a fixture holds the work while the tool moves independently, and a jig also controls where the tool goes. A drill jig is the clearest example. The bushing is the control, and the operator only has to push the drill through it. That is what turns a hole position from a layout skill into a repeatable step.
The useful consequence is that a jig can put a hole accurately into a part that is not itself accurate. A molded housing with draft, a casting with an as-cast surface, a formed bracket that varies across its bend: all of them are hard to mark out and easy to drill through a jig, because the jig locates on the datums the print names and ignores the rest of the part’s variation.
Bushings: the hardened part that does the work
Drill bushings are hardened, ground sleeves pressed or slip-fitted into the jig plate so the drill runs against tool steel rather than against the jig. Wikipedia’s Drill bushing entry (en.wikipedia.org/wiki/Drill_bushing) covers the families, and Carr Lane (carrlane.com/product/drill-bushings) and McMaster-Carr (mcmaster.com/products/drill-jig-bushings/) publish the standard sizes and press-fit hole data that a jig print should reference.
The type follows the job. A press-fit headless or head bushing suits a jig that only ever drills one size. A liner bushing with a renewable slip bushing suits a jig that drills then reams, or one that will wear out bushings in production and needs them changed without pressing anything out of the plate. Put the bushing part number on the print with its hole and the press fit, and the right hole is made for it rather than a hole that is nearly right.
Position tolerance, and what the plate has to hold
The hole the part ends up with is the sum of three things: where the bushing hole is in the plate, how much clearance the drill has inside the bushing, and how repeatably the part locates in the jig. Only the first is fully under the jig maker’s control, which is why bushing hole position is the callout that drives the plate. State it on the fixture print as a position tolerance from the same datums the part print uses.
The second, drill clearance, is why a jig drills to a hole size rather than a hole position in the tenths. If the print needs a precisely located and sized hole, the jig drills undersize and the part is reamed through a second slip bushing, or the feature is machined rather than jigged. CNC machining tolerances covers the bands; the quote will say plainly when a callout is tighter than a jig can deliver.
Trim jigs, and guiding a cutter along an edge
A trim jig does for an edge what a drill jig does for a hole: it presents the part on its datums and gives the cutter a hardened edge or a bushing to follow, so a molded flash line, a cast riser or a formed overhang comes off in the same place every time. The wear surface is the whole job, because a router bit bearing running on soft aluminum eats a trim jig in a week.
So trim jigs carry hardened and ground wear strips or a hardened top plate where the cutter runs. A2 and D2 are the usual grades: Hudson Tool Steel lists A2 heat treating to 60-62 HRC with good toughness (hudsontoolsteel.com/technical-data/steelA2) and D2 at 58-60 HRC, or 62-64 HRC in its most wear-resistant condition (hudsontoolsteel.com/technical-data/steelD2). Where a wear strip is replaceable, it goes on the print as its own detail with its own fasteners.
Holding an imperfect part without moving it
The part in a drill or trim jig is usually the awkward one: draft angles, an as-cast surface, a soft or thin wall, a finish that must not be marked. It has to be held firmly enough that drilling thrust or cutter load does not shift it, and gently enough not to deform. The answer is usually more contact area and less force: area pads rather than points, a nest that follows the part surface, a toggle clamp with a soft pad pushing toward a rest rather than across it.
Where the part is finished, the contact faces go to Delrin or UHMW so nothing marks, with the rest of the jig in aluminum or steel. Say on the print which surfaces are cosmetic and which are fair game. Chip and dust clearance matters too: a drill jig that traps swarf under the part lifts it off the rest on the second hole, so relief and open sides belong on the print.
What to send, what is inspected, and when it ships
Send the part model and a PDF print with the datums and the jigged holes or trim line marked, the hole sizes and position tolerances, the bushing part numbers you want, the part material and how much variation it carries, which faces are cosmetic, and whether the jig is handheld, bench-mounted or clamped down. Any file type is accepted, STEP plus PDF is ideal, and the quote lists what is still missing.
Every jig is inspected against its print before it ships. Hardness verification on the hardened details can be arranged and quoted. One jig is a normal order with no minimum. Rush 1-2 weeks applies to machined parts with no secondary operations. Heat treat, grinding, EDM and finishing add time, and the quote gives the real date. Standard lead time is 4-6 weeks, and extended is 6-8 weeks when timing is flexible. Lead time starts at order approval. Put your need date in the part description and the quote answers it.
Questions
Before you send a job.
01 What is the difference between a drill jig and a drill fixture?
A jig guides the tool as well as holding the part, usually through a hardened bushing; a fixture only holds and locates the part while the tool is positioned some other way. If the operator pushes a drill through a bushing, it is a jig. Both are quoted here from the same kind of print.
02 Which drill bushings should the print call out?
Press-fit head or headless bushings for a jig that only drills one size, and liner bushings with renewable slip bushings where you drill then ream, or where production will wear bushings out and you want them changed without pressing anything from the plate. Put the catalog part number on the print with its press fit so the right hole is made.
03 How accurate is a hole drilled through a jig?
The result is the bushing hole position in the plate, plus the drill clearance inside the bushing, plus how repeatably the part locates. That position is quoted from the print and inspected against it. The drill clearance is why a jig is not a route to a hole located in the tenths; for that the jig drills undersize and the part is reamed through a slip bushing, or the feature is machined instead.
04 Can a jig drill a molded or cast part accurately?
Yes, and that is the usual reason to have one. The jig locates on the datums the print names and ignores the rest of the part variation, so draft, an as-cast surface or a formed bend no longer has to be laid out by hand. Say how much the part varies and where it is soft or thin, so the quote accounts for it.
05 Do trim jigs need hardened wear surfaces?
Where a cutter or a bearing runs on them, yes. A router bearing on bare aluminum wears a trim jig out quickly, so trim jigs carry hardened and ground wear strips or a hardened top plate in A2 at 60-62 HRC or D2 at 58-60 HRC. Replaceable strips go on the print as their own detail with their own fasteners.
06 What should I send to get a drill jig quoted?
The part model and print with the datums and jigged holes marked, hole sizes and position tolerances, the bushing part numbers, the part material and how much it varies, which faces are cosmetic, and whether the jig is handheld, bench-mounted or clamped down. Any file type is accepted; the quote lists anything missing.
Related
Where to go next.
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Sleeve, flanged and wear bushings made to print.
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