1-6 Soft Foot

[@ogbonlaiyekassim4460]

you're the best Mr John

[@josephquattrocchi5620]

I want to thank you for training. It has been a desire to learn this topic for some time. I will further my knowledge, however I have a question. Assuming the technician verified a soft foot condition and took the steps as you outlined to correct this issue. Will the installed correct shims be damaged by over torquing the mounting bolts. My concern is the photo you showed at the beginning of the work out damaged shims. In reality a custom shim is a wedge and I believe it will be damaged by too much fastener torque. Use of very aggressive methods like pneumatic impact guns and then a slap wrench to finish the job.

[@shaftalignment6105]

Joseph - Good question. If a gap exists between the underside of a machine foot and the baseplate due to a soft foot condition, there is a possibility that when the foot bolt is torqued to its appropriate value, the foot does not bend enough to actually contact the foot pad on the baseplate leaving a small gap. When the machine is running, there is probably some (hopefully not a lot of) vibration that eventually "hammers" any shim that may be in between the foot and the base. This is called fretting corrosion. If however, there is no gap since the missing volume has been filled with a custom built, wedge shaped shim pack, and therefore won't be able to "hammer" the shims. Having one (or more) soft foot conditions when attempting to make alignment corrections is one of the two top reasons why one "chases their tail" when aligning machinery. I hope this has helped you. Thanks for watching the video. John Piotrowski

[@josephquattrocchi5620]

I work for a company that struggles with many adjustments come alignment time. Sad thing is they hired 2 reputable outside companies specializing in alignments. Both never measured soft foot as depicted in the video. I thank you for the info, it was an eye opener. I am looking into training and love to improve my skill set anyway that I can. This was an excellent video series and very generous of you to apply your time and expertise for the the enrichment of a fellow technician.

[@shaftalignment6105]

Joseph - You are more than welcome. As discussed and shown in the tutorials, soft foot is far more complex than most people realize. When you begin to think about it, the possibility of four (or more) surfaces on the underside of the machine feet and the four (or more) surfaces on the baseplate being perfectly flat and coplanar is very slim. The possibility of a perfectly even gap between the feet and the points of contact on the base that could be corrected with a single U shaped shim is highly unlikely. The most common occurrence is that there are complex, wedge shaped gaps between on (or more) of the machinery feet and the contact point on the baseplate or soleplate that will require a complex, wedge shaped shim set to correct it. The degraded shim in the tutorial was due to the soft foot NOT being corrected. Just because you tightened a foot bolt to it's correct torque value does not mean that the foot elastically bent to fill in the gap. If a gap exists between a foot and the base that was not observed nor corrected, when you tighten the bolt to it's desired final value, the foot may begin to bend trying to fill in the gap, but may not bend entirely and therefore leaves a gap allowing any residual vibration that occurs in the machinery during operation to "hammer" the shims underneath until they turn into a powder. This is called fretting corrosion. If however, you have filled in the gap with shims, be they U shaped, L shaped, strips, or corner pieces ... when you tighten the foot bolt, the shims will be pinched and no gap will exist to cause fretting corrosion or have one of the shims comes loose. Ideally you would like to have full annular contact around the bolt hole but at a minimum, you must have contact that crosses through the axis of the bolt. The shims won't be damaged because the gap has been filled in regardless of the amount of torque applied to the foot bolt. Disappointingly, very few people in industry have been properly trained on shaft alignment. Way too many people rely exclusively on their "alignment tool" to do the "thinking" for them. This problem has been persistent for a long time and a group of us finally got together a few years ago and began work on the first ever published standard on shaft alignment that sets forth guidelines for acceptability in ever aspect of machinery installation and alignment. It is published by the American National Standards Institute and the Acoustical Society of America (ANSI/ASA S2.75 Part 1). Standard No. 1 is entitled "AMERICAN NATIONAL STANDARD Shaft Alignment Methodology, Part 1: General Principles, Methods, Practices, and Tolerances" (global.ihs.com/doc_detail.cfm?&csf=ASA&item_s_key=00733271&item_key_date=910528&input_doc_number=&input_doc_title=&org_code=ASA&input_asa_filter=ASA-NULL-S2#abstract). Hopefully this has been of some assistance to you Joseph. Eventually I will upload 24 more tutorials on Shaft Alignment covering the Basic, Intermediate, and Advanced topics. John Piotrowski

[@josephquattrocchi5620]

Thanks for the link I just ordered a copy. Have a blessed day !!!

[@shaftalignment6105]

Joseph - Sorry for the delay in getting back. The is a less likely chance that the soft foot shims will be damaged (usually from fretting corrosion) compared to a single thickness shim. The reason is that the soft foot shims will be "pinched" between the underside of the machine foot and the points of contact on the baseplate preventing vibratory motion of the foot (due to the lack of contact) causing the fretting corrosion (hammering the metal into a powder) or cracking of the shim. Does that make sense to you? If not, I will try to explain it differently. Great question! - John Piotrowski

[@lahcenchaanbi7224]

Thanks John

[@madinacer6122]

Thank u sir for this video training.

[@shaftalignment6105]

Madi - Thank you for the kind comments (again). John Piotrowski

[@mustafashaikh4884]

Thanks sir

[@shaftalignment6105]

Mustafa - You are very welcome. I hope this will help you. John Piotrowski

[@shaftalignment6105]

Mustafa - Thank you for the kind comments. John Piotrowski