Chef's Choice Diamond UltraHone 312 User manual

MODEL 312 InstructIOns
Diamond UltraHone®Sharpener
Read these instructions before use.
It is essential that you follow these
instructions to achieve optimum results.
© 2016 EdgeCraft Corp.

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IMPORTANT SAFEGUARDS
When using electrical appliances, basic safety precautions should always be
followed including the following:
1. Read all instructions. Every user should read this manual.
2. To protect against electrical hazards do not immerse the Chef’sChoice®Model 312 in water
or other liquid.
3. Make sure that only clean knife blades are inserted in the Model 312.
4. Unplug from outlet when not in use, before putting on or taking off parts, and before cleaning.
5. Avoid contacting moving parts.
6. Do not operate any appliance with a damaged cord or plug or after the appliance
malfunctions, or is dropped or damaged in any manner.
U.S. customers: You may return your sharpener to EdgeCraft’s factory for service where the
cost of repair or electrical or mechanical adjustment can be estimated. When the electrical
cord on this appliance is damaged, it must be replaced by the Chef’sChoice distributor or
other qualified service to avoid the danger of electrical shock.
Outside U.S.: Please return your sharpener to your local distributor where the cost of repair
or electrical or mechanical adjustment can be estimated. If the supply cord of this appliance
is damaged, it must be replaced by a repair facility appointed by the manufacturer because
special tools are required. Please consult your Chef’sChoice distributor.
7. CAUTION! This appliance may be fitted with a polarized plug (one blade is wider than the
other). To reduce the risk of electric shock, this plug will fit in a polarized outlet only one
way. If the plug does not fit fully in the outlet, reverse the plug. If it still does not fit, contact a
qualified electrician. Do not modify the plug in anyway.
8. The use of attachments not recommended or sold by EdgeCraft Corporation may cause fire,
electric shock, or injury.
9. The Chef’sChoice®Model 312 is designed to sharpen household knives, pocket knives and
selected sports knives. Do not attempt to sharpen scissors, ax blades or any blade that does
not fit freely in the slots.
10. Do not let the cord hang over edge of table or counter or touch hot surfaces.
11. When in the “ON” position (Red flash on switch is exposed when “ON”) the Chef’sChoice®
sharpener should always be on a stable countertop or table.
12. WARNING: KNIVES PROPERLY SHARPENED ON YOUR CHEF’SCHOICE®WILL BE SHARPER
THAN YOU EXPECT. TO AVOID INJURY USE AND HANDLE THEM WITH EXTREME CARE. DO
NOT CUT TOWARD ANY PART OF YOUR FINGERS, HAND OR BODY. DO NOT RUN FINGER
ALONG EDGE. STORE IN A SAFE MANNER.
13. Do not use outdoors.
14. Close supervision is necessary when any appliance is used by or near children or the infirm.
15. Do not use honing oils, water, or any other lubricant with the Model 312.
16. For household use only.
17. SAVE THESE INSTRUCTIONS.

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YOU MADE
A GOOD
CHOICE
Professional chefs and serious cooks worldwide rely on Chef’sChoice®
Diamond Hone®sharpeners to maintain the edges of their favorite
knives at better than factory sharpness and durability. Chef’sChoice®
sharpeners are known for their consistent foolproof performance, ease
of use, and ability to create ultra sharp edges on quality cutlery with
minimal removal of metal.
The Chef’sChoice®Model 312 incorporates the latest technology
developed by Chef’sChoice®based on micron sized diamonds to
ultra hone your knife edge to astonishing sharpness. You will find it
fast and simple to use. The two stage design of Model 312 sharpens/
hones the edge first with fine diamonds to create a first bevel before
honing with ultrafine diamonds at a slightly larger angle to develop an
unusually sharp but durable edge. Diamonds, the hardest known
materials can sharpen knives made of any metal including the hardest
carbon, stainless and super alloy steels.
You will find renewed joy in using your favorite knives once sharpened
in the Model 312. The edges will be sharper and they will stay sharp
longer than conventional or hollow ground edges. Remember a sharp
knife is a safer knife because it requires less effort to cut or slice. The
Model 312 will reward you with years of added culinary pleasure and
bring extra appeal to each gourment creation. Enjoy.

UNDERSTANDING THE MODEL 312
DIAMOND ULTRAHONE®SHARPENER
This unique Chef’sChoice®Diamond UltraHone®Sharpener is designed to sharpen knives with
either straight or serrated edges. This two (2) stage sharpener has two precision sharpening /
honing stages,one with fine and the other with ultrafine 100% diamond abrasive.This combination
can be used to create either an ultra sharp, smooth faceted edge for effortless cutting and
presentations or one with a selected amount of residual “bite”.
The sharpening and honing actions are controlled by using precisely angled guides for the blade
and precisely matched conically surfaced abrasive disks. The sharpening angle is slightly larger
in Stage 2 than in Stage 1. The sharpening rate is carefully controlled by the size of diamonds
used and by unique internal springs that limit the amount of pressure that can be applied to the
edge by the abrasive disks.
Fine diamond-coated conical disks in Stage 1 create microgrooves along the facets on each
side of the edge establishing the first angled bevel of the edge. In Stage 2 precision disks coated
with micron sized diamonds gently hone and polish the facets immediately adjacent to the edge
creating a microbevel along a microscopically thin straight and polished edge. The honing ac-
tion simultaneously polishes and sharpens the boundaries of those microgrooves created by the
diamond abrasives in Stage 1 adjacent to the edge until they become sharp micro flutes that will
assist the cutting action with “difficult to cut” materials.
This unique two stage design gives you an extremely sharp edge and because of the second
angle microbevel, you will notice that your knives stay sharp longer than those sharpened by
conventional means.
The following sections describe the general procedures for optimal sharpening. One of the
important advantages of using the Model 312 is that you can hone and polish your knives to
razor sharp edges as often as needed and yet experience little knife wear compared to older
sharpening methods. Resharpening can commonly be done by using just the gentle ultra honing
action of Stage 2. (See Resharpening Section).
Each sharpening Stage is equipped with gray flexible plastic springs that are positioned over
the sharpening disks (see Figure 1) to hold the face of your knife securely against the precision
guides in the right and left slots of each stage during sharpening.
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Unless you have special blades designed to be sharpened primarily on one side of the edge
(such as Asian Kataba blades) you will want to sharpen equally in the right and left slots of each
stage that you use. This will insure that the facets on each side of the edge are of equal size and
that the edge will cut straight at all times.
When sharpening in either stage the knife should on sequential strokes be pulled alternately
through the left slot and the right slot of that Stage. Generally a few pairs of pulls (alternating
in the left and right slots) will be adequate in each stage (see subsequent sections for more
detail). Always operate the sharpener from the front side with the switch facing you. Hold the
blade horizontal and level, slide it down between the plastic spring and the guide plane while
pulling it toward you at a uniform rate as it contacts the sharpening or honing disk. You will be
able to feel and hear the contact with the disk as it is made. Always keep the blade moving
uniformly through each stage; do not stop the pull in mid stroke. The time for each sharpening
stroke can be less for shorter blades and more for longer blades.
Never operate the sharpener from the back side.
Use just enough downward pressure when sharpening to insure uniform and consistent contact
of the blade with the abrasive disks on each stroke. The sharpening pressure is controlled by
the internal springs positioned between the abrasive disks. Additional pressure is unnecessary
and will not speed the sharpening process. Avoid cutting into the plastic enclosure. Accidental
cutting into the enclosure will not functionally impact operations of the sharpener or damage
the edge.
Figure 1 below identifies each of the two stages as described further in the following sections.
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Figure 2. Typical kitchen knife.
Heel
Bolster
Handle
Edge
Tip
Figure 1. Model 312 Diamond Hone®Sharpener.
Stage 1 Stage 2
Flexible
Positioning
Springs

The Chef’sChoice®Model 312 is designed to sharpen either Straight edge or Serrated edge
blades. Follow these instructions for optimum results.
PROCEDURE FOR SHARPENING STRAIGHT EDGE BLADES
STRAIGHT EDGE BLADES: SHARPENING FIRST TIME
Always clean the blade free of dirt, oil and food before inserting into sharpener.
Before you turn on the power, slip a knife blade smoothly into the slot between the left angle
guide of Stage 1 and the plastic spring. Do not twist the knife (see Figure 3.)
Move the blade down in the slot until you feel it contact the diamond disk. Pull it towards you
lifting the handle slightly as you approach the tip. This will give you a feel for the spring tension.
Remove the knife and press the Power Switch. A red “indicator” on the switch appears when
this switch is turned “ON.”
Stage 1: If you are sharpening a straight-edge knife for the first time, start in Stage 1. Pull
the knife once through the left slot of Stage 1 (Figure 3) by slipping the blade between the left
plastic angle guide and the plastic spring while pulling the blade toward you and simultaneously
moving the blade downward in the slot until it engages the diamond coated disk. You will hear
it make contact with the disk. If the blade is curved, lift the handle just enough as you sharpen
near the tip of the knife to keep the blade edge in audible contact with the rotating disk. Sharpen
the entire blade length. For an eight (8) inch blade each pull should take about 6 seconds. Pull
shorter blades through in 3-4 seconds.
Figure 3. Stage 1. Inserting blade in slot between guide
and elastomeric spring. Alternate individual pulls in left
and right slots.
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Figure 4. Inserting blade in right slot of Stage 1. Figure 5. Develop a distinct burr along knife edge before
honing in stage 2. Burr can be detected by sliding finger
across and away from the edge. Caution! See text.
Next, repeat with one full length pull in the right slot of Stage 1 (see Figure 4)
Note: Each time you insert the blade, simultaneously pull the blade toward you. Never push the
blade away from you. Apply just enough downward pressure to make contact with the disk –
added pressure does not speed up the sharpening process.
To insure uniform sharpening along the entire blade length, insert the blade near its bolster or
handle and pull it at a steady rate until it exits the slot. Always make an equal number of pulls
alternating one pull in the left slot and then one pull in the right slot in order to keep the edge
facets symmetrical. Generally in Stage 1 you will find that only 3 to 5 pairs of slow pulls is
adequate, but for a duller knife more pulls will be needed.
Before moving to Stage 2 it is very important to confirm that a burr (see Figure 5) exists along
one side of the edge. To check for the burr, move your forefinger carefully across the edge as
shown. (Do not move your finger along the edge – to avoid cutting your finger). If the last pull
was in the right slot, the burr will appear only on the right side of the blade (as you hold it when
sharpening) and vice versa. The burr, when present, feels like a rough and bent extension of the
edge; the opposite side of the edge feels very smooth by comparison.
If no burr exists, make one or two pairs of additional alternating pulls in the left and right slots of
Stage 1 before proceeding to Stage 2. Slower pulls will help you develop the burr. Confirm the
presence of the burr after a pull in the left slot and then also after a pull through the right slot
before proceeding to Stage 2. It is always necessary to create the burr in Stage 1 before
honing in Stage 2.
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Stage 2: In general only two pairs of slow pulls (about 4-6 seconds each) followed by two pairs
of faster pulls (1-2 seconds each) in Stage 2 will be needed to obtain a razor sharp edge. Make
alternating pulls in left and right slots (Figure 6).
Fewer fast pulls in Stage 2 are preferable if you will be cutting fibrous foods as discussed in
more detail in the following section.
OPTIMIZING THE KNIFE EDGE
Gourmet Food Preparation:
Where the finest and smoothest cuts are preferred in preparing smooth unmarked sections of
fruits or vegetables, sharpen in Stage 1 and 2 as described above and make a couple of extra
pairs of fast pulls (1-2 seconds) thru Stage 2. The added pairs of such fast pulls with each
pull alternating in the left and right slots of Stage 2 will refine the second facet and create
remarkably smooth and sharp edges, (Figure 7) ideal for the gourmet chef.
When resharpening the Gourmet edge, first use Stage 2, (alternating left and right slots). If after
a number of resharpenings, it is taking too long to resharpen or to develop the keenest edge, you
can speed the process by resharpening again in Stage 1 following the procedures detailed, and
then resharpen in Stage 2. This procedure for sharpening, unlike conventional sharpening will
give you extraordinarily sharp knives every day
while removing very little metal and prolonging
the life of your knives.
For Game, Fish and Fibrous Materials
For cutting more fibrous materials such as
limes, lemons and meat you will find it advan-
tageous to sharpen in Stage 1 until a burr is
fully developed along the entire edge, followed
directly by only two or three alternating pair of
fast pulls in Stage 2. This will leave sharpened
microflutes along the facets nearer to each
side of the edge (Figure 8) that will assist in the
cutting of such materials.
Figure 7. A larger polished facet adjacent to edge is
ideal for gourmet preparations.
Figure 6. Inserting blade in left slot of Stage 2. Alternate
individual pulls in left and right slots.
Figure 8. Retention of larger microflutes adjacent to
edge helps when cutting fibrous foods.
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PROCEDURE FOR SHARPENING SERRATED BLADES
Serrated blades are similar to small saw blades with scalloped depressions and a series of
pointed teeth. In normal use the points of the teeth do most of the cutting.
Serrated blades of all types can be sharpened in the Chef’sChoice®Model 312. However, except
as noted below, use only Stage 2 (Figure 9) which will sharpen the teeth of the serrations and
develop sharp microblades along the edge of these teeth. The design of serrated edges varies
greatly but generally two (2) to six (6) pairs of slower (3-6 seconds) alternating pulls in Stage
2 will be adequate. If the serrated knife is very dull more pulls will be needed. If the knife edge
has been severely damaged through use, first make just one fast pull (2-3 seconds for an 8”
blade) in each of the right and left slots in Stage 1, then make a series of slow pulls in Stage 2,
alternating right and left slots. Excessive use of Stage 1 will remove more metal along the edge
than is necessary in order to sharpen the teeth.
Because serrated blades are saw-like structures, the edges will never appear to be as “sharp”
as the edge on a straight edge knife. However, their tooth-like structure can be effective for
fiberous foods or help break the skin on hard or crusty foods.
RESHARPENING
Resharpen straight edge knives whenever practical using Stage 2. When that fails to quickly
resharpen, return to Stage 1 and make 3 to 5 pairs of slow alternating pulls as described on
pages 6 and 7. Check for a burr along the edge and then proceed to Stage 2 where two pairs of
slow pulls followed by two or more pairs of faster pulls will be necessary as described above to
put a new razor-like edge on the knife.
Resharpen serrated blades using the sharpening procedure described in the preceding section
for serrated blades.
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Figure 9. Sharpen serrated blades only in Stage 2.
(See instructions.)

SUGGESTIONS
1. Because of the ultra fine diamond abrasives used in this sharpener, it is extremely
important to always clean all food, fat, and foreign materials from the knife before
sharpening or resharpening. If knife is soiled, wash it thoroughly before sharpening. If
food, oil or fats accumulate on the ultrafine diamonds of Stage 2 you will notice that it will
sharpen more slowly. In that event unplug the power cord from electrical socket, remove
the gray plastic spring marked #2 which is held in place by two black plastic “spring-pins”.
Use a small screwdriver to slip under the back of the plastic spring and pry it up until it is
loose. Remove the plastic spring. Save the spring and spring-pins and clean the Stage 2
diamond disks. To clean the disks use a small children’s toothbrush and a weak solution of
household dish detergent (such as Dawn). Prepare a solution of about 2 drops of detergent
in a cup of warm water. Place only a few drops of detergent solution on brush and scrub
the sharpening faces of the disks. Rotate the disks by hand to brush all areas of the disks
several times. Then rinse lightly with water on the brush. Always use a brush and minimize
the amount of water used. Cut a small piece of paper towel to pat the disks dry. Allow time
for disks to dry completely and be certain no water remains in sharpener before turning on
power. Reassemble the plastic spring and fasten in place with the two plastic spring-pins.
2. To increase your proficiency with the Chef’sChoice®Model 312, take the time to learn how
to detect a burr along the edge (as described on p. 7). While you may sharpen well without
using this technique, it is the best and surest way to determine when you have sharpened
sufficiently in Stage 1. This will help you avoid oversharpening and insure sharp edges
every time. Cutting a tomato or a piece of paper is a convenient method of checking for
blade sharpness when sharpening is finished.
3. Use only light downward pressure when sharpening – just enough to establish secure
contact with the abrasive disk.
4. Always pull the blades at the recommended speed and at a uniform rate over length
of blade. Never interrupt or stop the motion of the blade when in contact with the
abrasive disks.
5. Always alternate individual pulls in right and left slots (of any Stage used). Specialized
Japanese blades are an exception and are sharpened primarily on one side of the blade.
6. The edge of the knife blade while sharpening should, in general, be held in a level position
relative to the top of the counter or table. However, to sharpen the blade near the tip of
a curved edge, lift the handle up slightly but just enough to maintain the edge audibly in
contact with the abrasive disk.
7. There is no need or advantage to using a “sharpening steel” on knives sharpened on the
Chef’sChoice®Model 312. It is recommended that you keep the Model 312 readily
accessible and resharpen often, as described in the previous Sections.
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Figure 10. Clean-out cover under sharpener.
8. Used correctly you will find you can sharpen the entire blade to within 1/8” of the bolster
or handle. This is a major advantage of the Chef’sChoice®Model 312 compared to
conventional sharpening methods – especially important when sharpening chef’s knives
where you need to sharpen the entire blade length in order to maintain the curvature of
the edge line. If your chef’s knives have a heavy bolster near the handle extending to the
edge, a commercial grinding service can modify or remove the portion of the bolster near
the edge so that it will not interfere with the sharpening action allowing you to sharpen the
entire blade length.
NORMAL MAINTENANCE
NO lubrication is required for any moving parts, motor, bearings, or sharpening surfaces. Do
not wet abrasive surfaces except in the cleaning procedure as discussed in item #1 under
“Suggestions”. The exterior of the sharpener may be cleaned by carefully wiping with a damp
cloth. Do not use detergents or abrasives on exterior surfaces.
Once a year or so, as needed, you can remove metal dust that will accumulate inside the
sharpener from repeated sharpenings. Remove the small rectangular clean-out cover (Figure
10) that covers an opening on the underside of the sharpener. You will find metal particles
adhered to a magnet attached to the inside of that cover. Simply rub off or brush off accumulated
filings from the magnet with a paper towel or tooth brush and reinsert the cover in the opening. If
larger amounts of metal dust have been created you can shake out any remaining dust through
the bottom opening when this cover is removed. After cleaning, replace the cover securely with
its magnet in place.
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SERVICE
In the event post-warranty service is needed, return your sharpener to the EdgeCraft
factory where the cost of repair can be estimated before the repair is undertaken. Outside the
USA, contact your retailer or national distributor.
Please include your return address, daytime telephone number and a brief description of the
problem or damage on a separate sheet inside the box. Retain a shipping receipt as evidence of
shipment and as your protection against loss in shipment.
Assembled in the U.S.A. www.chefschoice.com
This product may be covered by one or more EdgeCraft patents and/or patents pending as marked on the product.
Chef’sChoice®, EdgeCraft®and the overall design of this product are registered trademarks of
EdgeCraft Corporation, Avondale, PA.
Conforms to UL Std. 982 Certified to CAN/CSA Std. C22.2 No. 64
Certified to EN 60335-1, EN 60335-2, EN 55014-1+A1, EN 61000-3-2, EN 61000-3-3
© EdgeCraft Corporation 2016
C16 C318206
®
EdgeCraft Corporation
825 Southwood Road, Avondale, PA 19311 U.S.A.
Customer Service [phone] or 610-268-0500
Send your sharpener (insured and postage prepaid) to:
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