Crankshaft grinding - video

[Toolmaker51]

Me thinks a set of video would answer, next person asking "why not" to running engine work.
They have no clue degrees of specialization between common machine tools and engine-work machinery with built in fixturing.

[Frank S]

I'm guessing not too many guys ever saw a crank ground while still in the block. Wouldn't work on today's high revving precision clearance engines, but back in the day my dad and I long before I was in my teens ground many a rod journals on an old tractor engine even some big truck gas engines without doing much more than dropping the pan and puling the head, snatching out the pistons and rods then grinding the journals enough to clean them up to an undersized bearing. usually right in the field with the plow still in the furrow. He and I sat on the side of the road once and he made a rod bearing out of a piece of his belt so we could make it the 100 or so miles home. Got home yanked the head and pan shoved his crank grinder down the cylinder bore ground that 1 journal installed an undersized bearing and ran the old truck for several more years.
I noticed there are several vintage in the block crank grinders for sale on Ebay similar to the one he had.

[Toolmaker51]

Not I certainly, least-ways in person, yet aware; especially tricks performed completing in frame overhauls.
Quite a range exists in 'bolt-on' aka 'portable' machine tools; journal squirrels, facing machines, boring bars (ie Frank S's avatar), keyway cutters, hand lathes... There might be portable broaches; mass needed to deliver rigidity makes that hard to imagine.

[Frank S]

Not I certainly, least-ways in person, yet aware; especially tricks performed completing in frame overhauls.
Quite a range exists in 'bolt-on' aka 'portable' machine tools; journal squirrels, facing machines, boring bars (ie Frank S's avatar), keyway cutters, hand lathes... There might be portable broaches; mass needed to deliver rigidity makes that hard to imagine.

My avatar wasn't named a Do- More- versi- mill for nothing. I use that thing for a multitude of things and since I has the 48" way bed for it I could either mount it on 1 end and use it like a lathe or mount it on the carriage and use it to mill long groves or whatever I used it as a drill press or a mill at times, as a tool post grinder at others it was a great supplementary tool for other machines or a standalone machine of its own.
My dad had an early model Kwik-way cylinder borer that we sometimes used to bore out a single cylinder of a tractor engine in the field or in the case of a @ cyl popping johnny John Deere tractor just bore out both cylinders as much as 0.100" on 1 old tractor, or bore out an entire engine if doing a rebuild.
People today would look on in horror if they saw someone do the things, we did without the aid of several hundred thousand of dollars' worth of fancy machines.

[hemmjo]

When you are in a "make do with what you got" situation, the goals and tolerances are different. This is especially true for an engine that is going to spend its life seldom running more that 1500-1600 RPM

I expect someone with a dedicated crankshaft grinding machine to do much better than "close is good enough".

[Frank S]

When you are in a "make do with what you got" situation, the goals and tolerances are different. This is especially true for an engine that is going to spend its life seldom running more that 1500-1600 RPM

I expect someone with a dedicated crankshaft grinding machine to do much better than "close is good enough".

Or at least not say it out loud for everyone to hear. It would have been the last one he would do for me. the old engines my dad did would last for 10 to 20 years seeing some pretty rough service even with the portable equipment he had there was no such thing as close enough unless the damage was to the extent that it could only be a temporary fix until it could be brought to him for a good tear down, which he would always tell the guy what really needed to be done. sometimes they listened and my dad would send the cranks and blocks out to a real engine machine shop to have all bores and journals matched correctly then build up the engines for them, other times it might be a couple years before they would have him pull an engine, transmission or rear end and replace with new parts. I never heard of one of his repairs even the ones he told the guy were only patch jobs to be the reason for causing a failure. After I got older learned how to weld and eventually bought my first lathe and welding machine his health had started going downhill so he had gotten rid of most of his equipment. When I finally brought the lathe home from the Blacksmith shop, he told me one day if he would have had one of those things back in the day, plus the portable equipment, he had sold he and I could have really done some things.