ACH-12
Accuhold End Mill Ultra Precision Extension Holder
Accuhold End Mill Extension Holder 0.37500-in ID, 0.75-in OD, 4.5-in OAL
Accuhold ultra-precision end mill extension holders — +.00015"/-0 hole tolerance to eliminate runout and tool breakage.
- Hole diameter tolerance +.00015"/-.00000 — the tightest-tolerance end mill extension, made to eliminate runout (TIR) and reduce tool breakage
- Reaches into deep parts: standard lengths 2-1/8" to 6-1/2" including -L long versions (ACH-04-L, ACH-06-L, ACH-08-L, ACH-12-L, ACH-16-32-L)
- Inch ACH line holds 3/32" to 1" tool shanks on 3/8" to 1-1/4" holder shanks
- ACH-M metric-to-inch line holds 3mm to 25mm tool shanks on inch holder shanks — converts an inch tool holder to metric tooling
- MAH all-metric line: 3-12mm holes on 10-25mm shanks, 82.5-150mm OAL
- Set screw sizes from 5-40 up to 7/16-20 matched to each holder
- Large sizes use stepped heads: ACH-16/M12 have a 1" dia x 1.5" head; ACH-24/32 and ACH-M18/M25 have 1-1/4" dia x 2-1/4" heads with 2" hole depth
- Shank tolerance -.0001/-.0003, OAL +/-.060
From the RobbJack Applications Guide.
About this series
ACH Accuhold End Mill Ultra Precision Extension Holders
The tightest-tolerance end mill extension to eliminate runout
The ACH Accuhold is an ultra precision end mill extension holder used to reach into parts that need longer length. Precision end mills need precision holders to eliminate runout (TIR) and reduce tool breakage. Inch hole sizes range from 3/32" to 1", with overall lengths from 2-1/8" up to 6" and matching set screws.
- Ultra precision extension holder
- Eliminates runout (TIR) and reduces tool breakage
- Hole Dia. tolerance +.00015/-.00000
- Shank Dia. tolerance -.0001/-.0003
- OAL tolerance +/-.060
Holds inch-shank end mills; the largest holders (ACH-24 and ACH-32) have a 1-1/4" diameter x 2-1/4" long head with a hole depth of only 2" deep
Headline spec
Inch hole diameters 3/32"-1"; overall lengths 2-1/8" to 6"
Best for
- Reaching into parts that need longer length
- Extending precision end mills while maintaining low runout
Specifications
US machining terms with ISO 13399 codes.
- Holder DiameterDMM
- 0.75″
- Accessory Type
- Extension Holder
- Overall Length (OAL)OAL
- 4.5″
- Series
- ACH — Accuhold End Mill Ultra Precision Extension Holder
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Tolerances
| Type | Min | Max |
|---|---|---|
| Hole Diameter | 0 | +0.00015 |
| Overall Length | -0.06 | +0.06 |
| Shank Diameter | -0.0001 | -0.0003 |
Made & shipped in the USA · lead time confirmed at order. Buy at retail or through your distributor.
Performance guaranteed. Run it against the tool you use today — if it doesn't beat it, we'll make it right.
Adds Uncoated · $330.80 — our pick for your material. Choose another finish below.
Proven in the field
- $548,290saved per year drilling carbon-fiber aircraft
- $216,000saved per year trimming aircraft skins
- 1,000%metal-removal increase in Inconel 718 (SPS)
Finishes (1)
Uncoated
ACH-12
$330.80
Available to order
Starting at
$330.80
Performance guaranteed
More in the ACH series
Same series, different size — what changes from this tool is shown in red.