Sealey DBG508 User manual

 WARNING! Ensure Health and Safety, local authority and general workshop practice regualations are adhered to when using
tools and equipment.
DONOT use the dial bore gauge if damaged.
DO NOT drop.
This is a precision instrument, always return gauge components to the internally lined storage case.
Maintain the gauge in good and clean condition for best and safest performance.
Keep the work area clean, uncluttered and ensure there is adequate lighting.
Ensure the work area floor is not slippery; wear non slip shoes.
Components to be measured and the dial bore gauge to be stored at room temperature (21°C).
INSTRUCTIONS FOR:
DIAL BORE GAUGE
MODEL NO: DBG508
1. SAFETY
DBG508 Issue: 1 - 19/06/15
Original Language Version
© Jack Sealey Limited
IMPORTANT: PLEASE READ THESE INSTRUCTIONS CAREFULLY. NOTE THE SAFE OPERATIONAL REQUIREMENTS, WARNINGS & CAUTIONS. USE THE
PRODUCT CORRECTLY AND WITH CARE FOR THE PURPOSE FOR WHICH IT IS INTENDED. FAILURE TO DO SO MAY CAUSE DAMAGE AND/OR
PERSONAL INJURY AND WILL INVALIDATE THE WARRANTY. KEEP THESE INSTRUCTIONS SAFE FOR FUTURE USE.
Thank you for purchasing a Sealey product. Manufactured to a high standard, this product will, if used according to these
instructions, and properly maintained, give you years of trouble free performance.
2. INTRODUCTION
Precision mechanism with Ø55mm dial and locking rotating bezel, offering an accurate method of measuring a bore or detecting a taper or
ovality. Will indicate the deviation from set size by up to 0.8mm with an accuracy of 0.01mm. Included with the bore gauge are; probe body,
dial indicator, anvils, spanner andspacer rings. Supplied in wooden storage case. .
3. SPECIFICATION
Model No: ..............................................................................DBG508
Measuring Range: .................................................................18-35mm
Maximum Deviation Measurement (dial bore gauge): ..............0.8mm
Maximum Deviation Measurement (dial gauge separate): ..........5mm
Dial Bezel Diameter:................................................................Ø55mm
Resolution:...............................................................0.01mm (0.0004")
4. CONTENTS
4.1. There are 3 main components-:
Item Description Qty
1 Dial gauge indicator 1
2 Probe body 1
3 Anvils and spacer rings 1-set

5. OPERATION
5.1. Setting up (The dial ball gauge is a comparator not a measuring tool)
5.1.1. Measure the bore diameter or gap to be measured to the nearest millimetre with a rule or vernier callipers. The bore or gap
must range between 18mm and 34mm nominally with this tool. (Up to 36mm with spacers)
5.1.2. Select the range of parts required, anvils and spacers using the table on the last page.
5.1.3. Assemble the dial bore gauge with selected parts as shown in fig.1 and fig.4. Ensure all components are clean before using the supplied
spanner to fit the required anvil/spacer requirement. DO NOT overtighten.
5.1.4. Insert the dial stylus into the probe body as shown in fig.4. The stylus will meet with resistance internally and the dial pointer will
begin to rotate clockwise. One complete cycle of the pointer is recommended for registration and will be indicated by the secondary dial
indicator annotated 1-5. The small pointer should now be indicating "1" [one].
5.1.5. Clamp the dial stem with the thumb screw. DO NOT overtighten.
5.2. Calibration
5.2.1. Depending upon accuracy requirement, calibration can be achieved with slip gauges, micrometer or vernier callipers. In our instructions
example the micrometer is suggested, which has similar accuracy to the dial gauge.
5.2.2. Set the micrometer (0mm-25mm) to the target size "x", for example Ø23.75 and lock. In our example the tolerance required is H9 from
BS 4500:1969 (+.052/-0).
5.2.3. From instruction 5.1.2 and the tables on the back page; parts required are either the anvil 24 ("x"=23.60-24.40) or anvil 22 plus spacer
ring 1.3 and spacer ring 0.65 ("x"=23.55-24.55), from fig.5. Assemble as shown above in fig.1.
5.2.4. Maneouvre the gauge anvil and nib inside the measuring gap of the micrometer (fig.11). This activity could be eased by assistance or
carefully clamping the dial gauge in a retort stand or similar.
5.2.5. Observe the large dial pointer movement. It is essential that the axis of the gauge anvil and spring loaded nib are centralised in the
micrometer measuring faces. It is essential to observe the total sweep of the dial pointer using the small dial. Remember from the initial
setting the pointer had rotated one full cycle.
5.2.6. When satisfied with alignment, hold the position and rotate the dial bezel until the "0" [zero] aligns with the pointer. Lock the bezel with
the thumb screw. Your dial bore gauge has now been calibrated for use in a Ø23.25 to Ø24.25 bore ie +/-0.25mm of target.
5.2.7. The tolerance band can now be set using the two "markers" on the bezel. Our example states the tolerance band to be +0.052 to -0. Set
one marker opposite and in line with "0" [zero] (fig.6) and the other +5.2 (fig.7) divisions apart. Note! the larger the deflection the smaller
the bore.
Nib
Anvil
see table on last page
Use the spacer rings to achieve "x" = 18.65, 19.30, 19.95:
20.65, 21.30, 21.95 etc..
Insert the stylus for 1 full large pointer revolution
g.4
g.1
Small pointer on "1"
Be aware, nib projection is 1.5 mm. Aim for
0.35mm to 1.15mm as the measurement zone.
DBG508 Issue: 1 - 19/06/15
Original Language Version
© Jack Sealey Limited
Nib
Nib total movement
Measurement zone = 0.8mm
Spacer
rings
Spring return self
centering guide.
(3 point location)
Anvil Bore
g.2
g.3
g.5
g.7
Pass Pass
Fail
Fail Fail
Fail
Lower Limit (+0.00mm) Upper Limit (+0.052mm)
Example only taken from
Calibration text 5.2.
g.5 g.6
Tolerance
markers

5.3. Accurate Measurement
5.3.1. Follow procedure 5.1.1 through 5.1.4.
5.3.2. The bore or gap machined finish must be clean with surface texture 3.2µm to 6.4µm or better than for fiducial indication.
5.3.3. Offer the anvil end into the bore at an angle (fig.8) with the anvil tip entering just ahead of the sprung loaded self centering guide. Rock
the dial gauge tube to the horizontal position (fig.9) and beyond, observing the pointer sweep. The three point location offered by the
spring loaded self centering guide and the anvil tip will align the head.
5.3.4. Rotate the bezel such that the "0" [zero] aligns with the largest sweep position of the pointer (fig.10). It is essential to observe the total
sweep of the dial pointer using the small dial. Remember from the initial setting the pointer had rotated one full cycle. Mark the position
on the component of where the measurement was taken, if required.
5.3.5. With a micrometer, measure across the anvil and the nib (fig.11), rotate the barrel of the micrometer until the dial pointer aligns with the
same "0" [zero] as the measured bore. Take the reading from the micrometer and record.
5.3.6. With the bore dial gauge now set, the bore can now be measured for taper and ovality by reference back to the initial datum "0" [zero]
reading and counting the 0.01mm divisions between datum and new. Note! the larger the deflection the smaller the bore.
g.8
"Offer the anvil end into the bore slightly tilted...." "Rotate the bezel such that the
"0" [zero] aligns....."
6. MAINTENANCE
6.1. Keep all components dry and clean with a soft micro fibre cloth.
6.2. Return all items to the presentation case after use.
6.3. Store indoors in a temperature controlled dry environment, circa 21°C.
6.4. This is a precision instrument intended for use by engineers and engineering inspectors, keep out of reach of children.
Component
DBG508 Issue: 1 - 19/06/15
Original Language Version
© Jack Sealey Limited
Component
g.9
g.10
"Rock the dial
gauge tube to
the upright
position....."

Environmental Protection
Recycle unwanted materials instead of disposing of them as waste. All tools, accessories and packaging should be
sorted, taken to a recycling centre and disposed of in a manner which is compatible with the environment.
Parts support is available for this product. To obtain a parts listing and/or diagram,
please log on to www.sealey.co.uk, email [e-mail] or telephone [phone].
NOTE: It is our policy to continually improve products and as such we reserve the right to alter data, specifications and component parts without prior notice.
IMPORTANT: No liability is accepted for incorrect use of this product.
WARRANTY: Guarantee is 12 months from purchase date, proof of which will be required for any claim.
01284 757500
01284 703534
[e-mail]
Sole UK Distributor, Sealey Group,
Kempson Way, Suffolk Business Park,
Bury St. Edmunds, Suffolk,
IP32 7AR
www.sealey.co.uk
Guide to Parts required versus measured size. (0.8mm graduations)
DBG508 Issue: 1 - 19/06/15
Original Language Version
© Jack Sealey Limited
g.11
A method for support and setting the micrometer
1.5mm Approximate Projection
0.35mm Approximately
0.35mm Approximately
0.8mm Useful measurement zone
"x" Anvil size Spacer ring
17.60-18.40 18 NO
18.25-19.05 18.65 0.65
18.90-19.70 19.30 1.30
19.55-20.35 19.95 0.65 + 1.30
19.60-20.40 20 NO
20.25-21.05 20.65 0.65
20.90-21.70 21.30 1.30
21.55-22.35 21.95 0.65 + 1.30
21.60-22.40 22 NO
22.25-23.05 22.65 0.65
22.90-23.70 23.30 1.30
23.55-24.35 23.95 0.65 + 1.30
23.60-24.40 24 No
24.25-25.05 24.65 0.65
24.90-25.70 25.30 1.30
25.55-26.35 25.95 0.65 + 1.30
25.60-26.40 26 NO
26.25-27.05 26.65 0.65
26.90-27.70 27.30 1.30
27.55-28.35 27.95 0.65 + 1.30
27.60-28.40 28 NO
28.25-29.05 28.65 0.65
28.90-29.70 29.30 1.30
29.55-30.35 29.95 0.65 + 1.30
29.60-30.40 30 NO
30.25-31.05 30.65 0.65
30.90-31.70 31.30 1.30
31.55-32.35 31.95 0.65 + 1.30
31.60-32.40 32 NO
32.25-33.05 32.65 0.65
32.90-33.70 33.30 1.30
33.55-34.35 33.95 0.65 + 1.30
33.60-34.40 34 NO
34.25-35.05 34.65 0.65
34.90-35.70 35.30 1.30
35.55-36.35 35.95 0.65 + 1.30
Enlarged copy of g.3 for clarity