Ok, now onto the V's,
need to set up and dress the angles first.
I will admit I did not take many pic's during the process, was busy doing it! so these pics are just mock ups of the set up.
Years ago I purchased this snazzy angle dresser from MSC, I think it was $35 about 20 years ago, money well spent! you can use a sine bar, or wedges, or even a simple protractor to set the angle. 1 bolt tightens it up and its set solid, then with the little handle it slides back and forth, a small key way keeps it in line in the housing.
Ok, after all the flats and verticals where done. I dug out my dressor, a set up cube I have, and a few 1-2-3 block. on the headstock end is a pad for the quick change box mounts to. set the cube against it. lined up the dressor all square and true. loosened the clamp and held the slide shaft against the V in the unworn area under the headstock, clamped the base of the dressor to the cube , then tigthened the angle clamp. this should set the angle I need, never measured, it, dont know what it is right now. will figure that later, keep it simple!
backed the dressor away from the bed a bit. placed an Indicator on the slide of the dressor and indicayed it into the angle of the V, taped it a bit till it indicated pefect! now the angle on the wheel will match the way! easy way,,, no fuss and matches perfect. and the best part, turn the dressor 180 and dress the same exact angle on the other side of the wheel with no fuss! the perfect KISS principle.
next I brought the wheel down over the low flats that I just finished. backed of about .005 for clearance, this will make sure i grind the full length of the angle but not touch what is finished already.
then bring the wheel around to the front. space the dressor out a bit so it will slide. keep it square and true to the ways and machine travels.bring the wheel over infront of the dressor, with it lined up exactly under the bottom as well as you can. if you are off center this starts changing the dressed angle.
start everything up, full mag on the chuck. slowly feed the spindle back till the diamond touches. now slide the slide on the dressor back and forth carefully while at the same time stepping the wheel back. keep the dressor cleaned and oiled and it will slide smothly. once you have dressed enough of the wheel to get the whole surface, take a few light dressing passes as smooth and evenly as you can. a few back and forth gets any loose grit of the wheel. drop the slide down and check to make sure everything clears to start grinding.
I brought the wheel back till it was very close to the front V. dressing the back of the wheel alows me to grind the front of the 2 V's. want to grind everything in the same set up so everything is as parrallel to each ohter as close ass posible. if you flip or change the set up, you will never get it back perfectly in line, period,
started the table travel in slow speed , figuring I will get the best finish just like I did the flats.
while the table is slowly traversing i stepped the spindle back till it just touches the v. I had marked up the V with a magic marker and could tell my dress exactly matched the existing angle on the unworn ends. slowly stepped it back about 2 or 3 tenths on each stroke, sorta side wheeling the surface but could tell I was going to have an issue. stepped it back about .010 to clean the surface up, started to let it spark out but could tell the finish was crappy and un acceptable!!! backed of quickly. here is where the 45 year old grinder bit me. the thrust bearings on the spindle are way loose. with the wheel having no real load it will float a bit along the length of the spindle giving a hipity hop hipity hop finisg that you could see the crowns where about 1/2 an inch apart!!!! crap. I did not want to get into repairing the grinder right now!!! thought about it a bit. radially the bearings are fine, when side wheeling the verticals , they came out perfect!! indiacted with in a tenth, but side wheeling this angle of aroud 45 degrees is coming out bad. figured the wheel at the vertical was getting enough side load to keep it up against the bearing surface, the angle being mid way does not have enough force at very light cuts to keep it against the thrust bearing. scrathed my head, thought about it a bit. restarted everything up again, but this time put the table in fast speed, about 3 times faster than low. brought it up to the v, started grinding again. stepped over about .0003 each pass, enough to keep a load on the wheel but not to much to cause heat issues, let it take about 3 passes with now step overs but not a spark out. finish came out very nicely!! can barley see the slightest hint of any waver. set up the .00005 indicator and checked the fresh ground v at a couple of hieghts along the length,,, perfect, no waver on the indicator!!!! now we are cooking with gas!
did the typical cool down, redress the wheel. retouch and respark the surface. rechecked and still perfect, dropped the wheel over into the center and repeated the whole process on the front of the rear V. checked when done and verified it was true to!!
not the best way to check but will tell you if you are grinding true to the ways of the grinder. if the grinder is grinding a huge arc, you will be grinding the same onto your part. more on this later.
ok, flipped the dressor around 180 and repeated the dressing steps on the front of the wheel. dressing a 22 inch by 6 inch wheel with a little hand slid dressor is a little un nerving. just take time, be carefull, dont get the fleshy parts any where they could get hurt! carefull and slow is the important part!
now repeat this whole process on the back of the front v and the back of the rear v. the whole ruff in, then cool , redress, respark.
everything looks good!! perfect surface finishes, no burns, no burnished looking grind surfaces!
came back and did my finall indicator checks,,, all this over 66 inches of length.
front v , with in a tenth, rear of the front V a couple of tenths same as the rear v's, front tailstock flat reads .0003 low in center, the back carraige flat now reads .0005 tenths,, ok we got some movement somewhere, probably from grinding the V's a little heat moved the rest. tried cheating while taking the smallest amounts and finishing each surface as I went, I knew this was going to happen. but also wanted to see how much it would to for later info. If I had more time and more wheels I would of roughed each surface first , then finished all later. but I have some time constraints on the machine being tied up. and the fact that these wheels are about $500 each! so I would have to dress a tone of sand of to get back to being able to sidewheel the verticals again. but in the worst case. If I am off by .0005 over 66 inches. that is only about 90 millionths of an inch per foot, not worth losing sleep over!
ok, cleaned everything real good, pulled the bed of the grinder and placed it on my work bench. cleaned it very well. took a fine scothbrite pad and sofly rubbed the ground surfaces down clean removing any swarf, fine burs and the sharpest of edges.
placed the tailstock base on the ways. ran an .00005 indicator from the base to the front vertical. slid it back and forth along the length, perfect, no waver! ok. checked it on the front face of the V, within a tenth!!, the back a couple, the rear flat showed a few tenths, ok,,
placed the carraige in front of the tailstock base placed the indicator onto the center of the carrage over the fron V to minumize the effects of the heavy wear on the v's of the carraige. just looking for quick ruff #'s right now. they track with in a tenth or two of each other!!!!! same as the back of the carraige as well as the front vertical of the carraige. this shows that the carraige and the tailstock are travelling true to each other with in a tenth or 2!! cant ask for better! grabbed the presicion level, the bed has a few thousandts twist in it end to end sitting on the wood workbench,,,,,, this bed is a bit of a noodle, before i can go much further I need to refinshes the base and get everythin reassembled and perfectly levelled out before i start final fitting everything back together.
but I wanted some solid #'s to define how well this grinder grinds and how "perfect" my lathe bed is... called my buddy who has a big Starrett surface plate. 4 by 8 foot! load it all up and went over. again cleaned everything as clean and sterile as we could, he was wondering as it is actually his grinder and he has never had any luck grinding his parts on it! so we get it all set up. flat and true on his surface plate. all 4 corners measure within a tenth using .0001 indicator,,,, the front flat drops ,,,,, .0003 in the center, the back flat,,, .0005 in the center. just like it showed on the grinder, kinda proves the grinder is well set up!!!! and that the lathe bed is ground pretty true!
by the time you play the travel and distance #'s the tailstock and carraige travels are with in a couple of tenths true to everything and each other!!!
Luckily one of the big machine builders was visiting Brian during this time and he was very impressed with the results of the lathe bed. he gave me a quick refresher class on scrapping to boot!
this was a real boost!! and made me feel even better about this whole project!!
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