Mt5 test bar in phoenix AZ

M

mike96

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As the title says, I am looking to borrow an mt5 test bar to make sure the headstock on my lathe is properly aligned. To the best of my knowledge it has never been removed however it is a second hand lathe so I would like to double check. Never hurts to be safe...

Mike
 
I'm sorry to be the first one to tell you this... But unless you find a Taft Pierce or other reputable one, you are wasting your time.

The offshore test bars are complete junk. I know 4 guys in my town that bought Mt3 and Mt4 test bars - and none of them are straight or in line with their taper.

Do a search on this site for 'align headstock'. It has been covered several times. 'too long didn't search' version is that you chuck up a bar and turn it. based on the taper you get, you can align the headstock. better detail has been covered several times.
 
Agreed, make your own test bar using the two collar method in the "how to run a lathe" South Bend book
-M
 
To be fair, I bought an MT3 alignment bar, from India, for 50 bucks. I was actually surprised with the quality...same diameter everywhere measured with Mitutoyo digital mic, worked fine for tailstock alignment...turned out I didn't need to make any adjustments. Now that I have it, I agree it's not fully necessary. It does give a quick check, faster than the two collar test.

I also have an MT3 to MT5 sleeve that fits my headstock, that also was OK.

Don't think I would purchase this again, but not for quality reasons.
 
I have annold SB book running around that came with the lathe, I will have to take a look at the 2 collar method mentioned.
 
The RDM method, aka Rollie's Dad's Method, doesn't require any turning and as long as the bar is of uniform roundness and diameter, it is just as accurate as a test bar. The bar doesn't even have to be straight. The bar can be chucked in the 3 jaw and doesn't require adjusting for zero TIR. It has the added advantage over the twin collar method in that it can also measure vertical misalignment. I have a 1-1/4" x 20" bar of centerless ground round that I use. For chuckles, I mounted and checked my lathe. I measured a .0014" drop in 17" vertically and .0005"/17" horizontally. . Considering the last time I aligned the lathe was more than a year ago, I think it is pretty good.

One thing that none of these methods can do is distinguish between headstock misalignment and bed twist. Since I havw ni way odf adjusting perpendiculaity of the cross slide, I check that first. A surface can be faced and a test indicator used to check a point near the edge from front and rear positions. If the cross slide travel is perpendicular to the spindle axis, the readings will be equal. I actually use a boss mounted on my faceplate. My assumption is then that any indicated taper using the two collar test or the RDM method is due to bed twist.
 
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