Fundamentals of Boring (Manual Lathe) 

Yup Ill add some fire to spice up my next video haha. Thanks for watching. I'm going to add better camera angles and information in my future videos.

He was talking about why it cuts again when you take a "spring pass". As someone else already mentioned though, if you don't change the depth of cut and do the same feeds/speeds, then that deflection also remains a constant. What I do is when I start approaching the finished size, I alter the depth of cut a few passes away from final size so that the remaining cuts can all be the same depth of cut so you can still cut deep enough for a good surface finish which you typically don't get when making multiple spring passes. On my lathe (a 9" x 20", so not the most rigid of machines), I typically shoot for multiple passes between .010 - .025" for the last 2-3 passes, checking size each time. If I need to alter the last pass by .001' or so, then the change in deflection is rather minor.

I don’t how anyone else does it, but I square my tool post up with the centerline by placing a 123 block between the chuck face and the tool post. Just run the tool post far enough in to enable placing the 123 block squarely between them, run the carriage to the left until it squeezes the block and squares up the tool post, then lock the tool post down. Takes about 20 seconds!

@@tomt9543 great, thanks for your explanation

This is delayed but I figured Ill answer anyway. To my knowledge it is not, I say this because this machine is 20 years old and we have always used it this way. Ill look more into it but the older guys told me "no its fine". I have seen it save a lot of tool posts in my career so far.

You can set your boring bar on center without issue. I routinely set a 2"/50mm devibe boring bar exactly on center and stick it out 20"/500mm and have no issues with clearances even when taking a cut that causes the bar to dive 1/8"/3mm down. Bars are designed to have clearance on center, and a lot of machines have no adjustment for tool height anyway. The only time I ever have a bar rubbing on the bottom of the bar from lack of clearance is when I am trying to deepen an already existing shoulder in a large bore and move my tool to a diameter smaller than the bar can allow (because the bore is large enough to accommodate being that far back without hitting on the back side of the tool) The most common inserts, *NMG (N=0 degrees), have no clearance and instead the bar will have the clearance built into it (usually -5 degrees), while Inserts in the *CMT (C=7 degrees) or *PMT (P=11 degrees) lines have clearance built into the flank of the insert (which is why you also only have one usable side of the insert opposed to both sides with the 0 degree clearance inserts). The distinction isn't whether it has a positive/negative chipbreaker , but the style of insert. The *CMT and *PMT insert styles and the accompanying bars are usually smaller bars (3/4" or smaller typically) and have less material to make the insert pocket and clearances with so they leave the pocket flat and grind the clearances into the inserts themselves. Long story short, if the bar fits in the hole, it's designed to have clearance in that hole on center with whatever insert fits in the pocket.

Thanks for the support! Hope this information is helping someone out there.

Machining-Tutorials I’m in a machining program as part of my high school education, u are helpful

You're*

Jeff Vader are u a machinist?

@@imperfectperfectionist9853 it's a pun lol