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B&S Micromaster Series II inspection and question

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Can some of you more experienced reconditioning guys have a look at this thread and give me some advice? I've torn this machine down and want to do whatever needs to be done before putting it all back together. It is currently not feeding well at the extremes of saddle travel - the cross feed steps are small like there's resistance or binding, but only at the ends, and much more so at the rear. I've also noticed there is no scraping or oil flaking anywhere - is this normal for these machines? Anyone else had a Micromaster table off and can confirm whether they were originally scraped or flaked? I did find an old Series II brochure that shows the machine with the table off and it sure doesn't look like the ways were flaked or scraped in the photo but it's a digital photo of a screen printed brochure so it isn't the clearest.

https://www.practicalmachinist.com/...aster-alive-cross-feed-problem-though-379187/
 
To avoid this thread going out of scope, I believe that eKretz just discovered the reason of binding (and it has nothing to do with stick slip, ways alignment, etc. Somebody has replaced the support for the spline shaft and "forced it into position-i.e. the holes don't align correctly with the original ones).

Let's focus on the design of the machine (pressure lubricated ways) and the pros and contra of flaking the unexposed ways.

Paolo
 
Richard King has repeatedly taught and written that unflaked ways have a tendency to wring together. I think the "pressure lubrication" here is no more than the standard slow feed of oil to a long angled groove. So if the machine were mine I'd at least put oil pockets in the top surface (table). I am told that this is also the shorter of the way surfaces, so that's clearly the best choice for keeping dust and dirt out.
 
Actually the two surfaces are of equal length in this case, I measured both after you posed the question in the other thread. They are both 32" in length, so at maximum longitudinal table travel in either direction there's 11" overhang and 21" still in contact. The pressure lubrication in this case is set at about 7psi, and is set with a relief valve. The manual recommends a minimum of 5-6 psi. It can be set higher for more lubrication if necessary as well as metering valves could be changed. As I understand it a balance needs to be struck - enough oil to keep things moving freely but not so much as to cause excess "float." I do think it's a good idea to oil flake at least the underside ways of the table and the underside ways of the saddle/upright.
 








 
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