Re: [multimachine] What accuracy does a machine shop machine blocks to?
- In the past when castiron blocks were used it was a practice to have graded pistons in steps of1 or 2 thou and this allowed for tool wear on a run on a production line.When reboring these tolerances were tighter as the cutting tool could be reset between boring each cylinder.When boring off line it was the normal prctice to have a guide plate bolted to the block.This was used on mini blocks to enable pistons from a hillman imp to be fitted and move the centres of the two outer bores further apart.As with most operations it depends on the skill of the machinist.A engineer leaving the collage of enginering were he was a tutor saw a group of men laying paving slabs in a decorative pattern.He engaged one of the men in conversation.On being asked by one of the group what he did the man replied that his subject was measurements and he worked to microns."You 'd be no good for this job"came the reply "the foreman said they had to be spot on"mikeFrom: Adam Simmons <xyrthx@...>
Sent: Wednesday, 3 July 2013, 15:24
Subject: Re: [multimachine] What accuracy does a machine shop machine blocks to?It depends a LOT on the quality of the machine shop. Most should be able to get them within a couple thou, and squareness depends on the quality of the level they're using.Unfortunately, there are pretty big stock windows on these dimensions. If you have a specific block, I can call a buddy @ a machine shop and see what the allowables are.- AdamOn Wed, Jul 3, 2013 at 5:50 AM, Petera <apples0_17@...> wrote:For a 90degree engine ie a v8. How accurate can a machine shop square up the the left and right cylinder banks to one another? Because if that is out from the start your accuracy overall will take a hit.
What about getting a block decked, and also getting the bottom of the block faced as well. I wonder how parallel they get it to one another?