Glossary entry (derived from question below)
English term or phrase:
taking of leads
English answer:
using lead wires to measure the clearance
Added to glossary by
humbird
Nov 24, 2008 04:12
15 yrs ago
2 viewers *
English term
taking of leads
English
Tech/Engineering
Mechanics / Mech Engineering
This is a pasage describing ship's steam tubine bearing maintenance.
Bearing oil film can affect depth micrometer readings, bridge gage readings, and the **taking of leads.**
I am stuck with this.
Are they talking about physical "lead" or else?
Bearing oil film can affect depth micrometer readings, bridge gage readings, and the **taking of leads.**
I am stuck with this.
Are they talking about physical "lead" or else?
Responses
5 hrs
Selected
using lead wires to measure the clearance
... an interpretation gleaned from several sources found by googling.
A lead wire or wires with a diameter larger than the expected clearance is/are placed between the two mating parts, the bearing is assembled (which crushes the relatively soft lead wire(s) to a thickness equal to the clearance), the bearing is disassembled, and the wire() is/are removed and measured.
refs:
ROOT CLEARANCE.—The designed root clearance with gear and pinion operating on their designed centers can be obtained from the manufacturer’s drawing or blueprint. The actual clearance can be found by taking leads or by inserting a long feeler gage or a wedge gage.
http://www.tpub.com/content/engine/14075/css/14075_124.htm
It is recommended that a crush check be done to verify a proper bearing to case fit. Place shims .005"/.010" thick along the case split line on either side of each bolt location. Lay a strip of plastigage or lead wire parallel to the axis of the machine on the top of the bearing shell. The standard design specification for the bearing shell crush is metal-to-metal to .002" interference. The plastigage should be chosen such that the thickness of the shims at the case split line falls in the middle of the plastigage range.
www.waukbearing.com/downloads/WBC_(US)_TPJ_Instructions.doc
--------------------------------------------------
Note added at 5 hrs (2008-11-24 09:25:44 GMT)
--------------------------------------------------
Here 'lead' means the metal (element) lead.
--------------------------------------------------
Note added at 7 hrs (2008-11-24 11:57:56 GMT)
--------------------------------------------------
For an alternative interpretation of 'bridge gage', see:
Bridge gages. Bridge gages are used to measure the amount an engine main bearing has dropped due to wear. Figure 2-5 shows a bridge gage in use. The upper cap of the main bearing has been removed and the bridge gage has been placed over the journal as shown. A feeler gage is then inserted between the tip of the bridge gage and the journal. The measurement recorded by the feeler gage is then compared to the original measurement taken at the time the engine was installed or with previous bridge gage readings...
www.maritime.org/fleetsub/diesel/chap2.htm
A lead wire or wires with a diameter larger than the expected clearance is/are placed between the two mating parts, the bearing is assembled (which crushes the relatively soft lead wire(s) to a thickness equal to the clearance), the bearing is disassembled, and the wire() is/are removed and measured.
refs:
ROOT CLEARANCE.—The designed root clearance with gear and pinion operating on their designed centers can be obtained from the manufacturer’s drawing or blueprint. The actual clearance can be found by taking leads or by inserting a long feeler gage or a wedge gage.
http://www.tpub.com/content/engine/14075/css/14075_124.htm
It is recommended that a crush check be done to verify a proper bearing to case fit. Place shims .005"/.010" thick along the case split line on either side of each bolt location. Lay a strip of plastigage or lead wire parallel to the axis of the machine on the top of the bearing shell. The standard design specification for the bearing shell crush is metal-to-metal to .002" interference. The plastigage should be chosen such that the thickness of the shims at the case split line falls in the middle of the plastigage range.
www.waukbearing.com/downloads/WBC_(US)_TPJ_Instructions.doc
--------------------------------------------------
Note added at 5 hrs (2008-11-24 09:25:44 GMT)
--------------------------------------------------
Here 'lead' means the metal (element) lead.
--------------------------------------------------
Note added at 7 hrs (2008-11-24 11:57:56 GMT)
--------------------------------------------------
For an alternative interpretation of 'bridge gage', see:
Bridge gages. Bridge gages are used to measure the amount an engine main bearing has dropped due to wear. Figure 2-5 shows a bridge gage in use. The upper cap of the main bearing has been removed and the bridge gage has been placed over the journal as shown. A feeler gage is then inserted between the tip of the bridge gage and the journal. The measurement recorded by the feeler gage is then compared to the original measurement taken at the time the engine was installed or with previous bridge gage readings...
www.maritime.org/fleetsub/diesel/chap2.htm
4 KudoZ points awarded for this answer.
Comment: "Thank you for your detailed answer. Everything you said makes sense in given context."
37 mins
bridge Gauge readings and taking of "loads"
Oil has a viscosity reading and the higher the viscosity the thicker the film and the sheer point (Generally) Heat, pressure and other factors come into play) Bearings have a tolerance to work in and this tolerance is sometimes in micro measurements ie; 0.0005mm a bridge gauge is a plastic gauge (plastiguage) which is placed in between the bearing and the bearing race, the pressure squashes the plastiguage and then you measure the thickness.
This gives you the bridge tolerance, or the distance between the bearing and the race (smooth surface), having oil there will give you a false reading.
Having a film of oil will give you an incorrect reading of the LOAD carrying capacity of a bearing. When a bearing is checked it must only have the correct oil or the correct grease, If you are using grease and there is oil on the bearing the bearing will give you a totally incorrect working load capability.
In fact, if there is oil in a bearing that is meant to only have grease in it, it will overheat and burn out when working.
I think you are looking for "Taking of Loads"
A glossary of bearing terms;
http://www.timken.com/EN-US/Knowledge/Pages/BearingGlossary....
--------------------------------------------------
Note added at 41 mins (2008-11-24 04:53:18 GMT)
--------------------------------------------------
http://products.ihs.com/bs-seo/gbm12_12.htm
--------------------------------------------------
Note added at 2 hrs (2008-11-24 06:23:26 GMT)
--------------------------------------------------
Taking Load readings, Recording Load readings, Recording Load strain,
--------------------------------------------------
Note added at 6 hrs (2008-11-24 10:32:29 GMT)
--------------------------------------------------
Bridge gauge readings are done using lead wire and plastiguage, I believe they are talking about 3 different inspections;
1/ depth micrometer readings
2/ bridge gauge readings
3/ taking of loads
This gives you the bridge tolerance, or the distance between the bearing and the race (smooth surface), having oil there will give you a false reading.
Having a film of oil will give you an incorrect reading of the LOAD carrying capacity of a bearing. When a bearing is checked it must only have the correct oil or the correct grease, If you are using grease and there is oil on the bearing the bearing will give you a totally incorrect working load capability.
In fact, if there is oil in a bearing that is meant to only have grease in it, it will overheat and burn out when working.
I think you are looking for "Taking of Loads"
A glossary of bearing terms;
http://www.timken.com/EN-US/Knowledge/Pages/BearingGlossary....
--------------------------------------------------
Note added at 41 mins (2008-11-24 04:53:18 GMT)
--------------------------------------------------
http://products.ihs.com/bs-seo/gbm12_12.htm
--------------------------------------------------
Note added at 2 hrs (2008-11-24 06:23:26 GMT)
--------------------------------------------------
Taking Load readings, Recording Load readings, Recording Load strain,
--------------------------------------------------
Note added at 6 hrs (2008-11-24 10:32:29 GMT)
--------------------------------------------------
Bridge gauge readings are done using lead wire and plastiguage, I believe they are talking about 3 different inspections;
1/ depth micrometer readings
2/ bridge gauge readings
3/ taking of loads
Note from asker:
| Thank you for your answer Gary. However, while I should not emphasize this, the source is very unlikely to have a typo. |
Something went wrong...