wondering about getting a cylindrical grinder

[michiganbuck]

You might give your tool post and even your compound a reasonable whack to see that all is solidly fixed. *Yes with the likes of a paint mixing stick as a whack-on cushion so as not to mar or break something. Could be a bolt is too long and bottoming out so not tightening something down solid.

Cutting forces could be easily 100 pounds or a few hundred pounds and that can push something that is not bolted down tight. An easy pull on a 3/8 bolt might be 1000 pounds of force pulling something tight..and a lathe may need 1000 to keep the tool post from turning. A bottom-out bolt may be lacking the force needed to pull something down.

QT:{ people that have grinders dont use them much is the feeling Im getting here.] Because lathes are not designed for abrasive grit and so the grit gets into the lathe worked and causes high wear.

How does the top of your lathe bed V way look? could it be bottom out at the top of the V. Ways so wore out that the portion that should have contact does not have contact so riding on the top of the V way.
Or another way to say this is the saddle riding on the bed ways as it should. *You should see oil wiping evidance.

 

[Milland]

Yeah, if levering the spindle only gets you a thou or so, there's something else going on.

 

[michiganbuck]

lever it up and down, to and fro, and end to end. I think you have done all this.
A one-hand pull/push on a 2x2 should be enough with no Breaking Something worry.

You should see a quick snap of a movement and that is all you want to see, you are not trying to bend something just see the free move.

 

[JST]

The thing that sticks out to me is that deal with the TPG.

Big, obvious difference with a TPG is infeed pressure. Nearly nothing with a TPG, plenty, depending on tool geometry, with a cutter.

A good heavy crosslide (or saddle), such as a Monarch would have, will not be moved by the pressure of a TPG. But cutting forces could do it.

Shake everything.... try to twist everything. Something is moving, and it seems not to be the spindle in its bearings.

A common one.....

Rocking horse wear in the saddle. The "wings" of the saddle wear sloppy out at the ends so that the saddle can shift with cutting forces, etc. With a big saddle, might not be easy to see. Get a lever connected to the carriage, maybe to the topslide/ompound and check if you can get the ends of the saddle wings to shift.

If the saddle does not shift, check every other part of the system, crosslide, compound, etc. Even the toolpost.

 

[michiganbuck]

this might be a good lathe, or not
engine lathe heavy duty - tools - by dealer - sale

 

[Jim Christie]

You perhaps know about this already, but if your tool bit is not set on center or above you will have problems getting a finish and holding sizes especially if the lathe is worn and drops down as you turn towards the chuck or there is a lot play in the cross slide and compound feed nuts the too will tend to get pulled in as it goes below center.
I gave an explanation in these threads.
Post 142
https://www.practicalmachinist.com/...dex8.html?highlight=Centre+Height#post1657816
and this link ,
International Library of Technology: A Series of Textbooks for Persons Engaged in the ... : International Textbook Company : Free Download, Borrow, and Streaming : Internet Archive
from post 76 in this gives a good explanation of the theory behind it.
https://www.practicalmachinist.com/...6889/index4.html?highlight=Tool+Centre+Height
Jim

 

[idacal]

I put some indicators on it to check for rocking not seeing it but not sure how to do it the crosslide and compound are pretty loose I need to tighten those gibs up again. I rechecked the saddle drop measuring off the tail post slides and its .010 on the front v and .05 on the rear flat but its consistent steady drop for about 30" so that shouldn't be causing my variations in a few inches. I could be getting some drastic rise when up tight close to the chuck have to pull the chuck off to measure the rise up tight against the headstock. but I put a piece of 4" stock 5" long in the chuck and did multiple cuts with a dnmg 543 insert with indicators set at various corners orf the saddle and not seeing the movement between loaded and unloaded i put drag on the feed wheel and that seemed to help the most but still was making hills and valleys. but i will keep working at it. I took pictures there is no uniformity to the variations but with as small of pictures as they allow here nothing can be seen
i did not put indicators on the cross slide will do that tomorrow and see if it is and work my way up

 

[john.k]

Guy with a similar problem....chucks are all stuffed,jaws hold only at back ,and allow work to pivot no matter how tight the key is turned ....jaws are also loose in mortices ,due to wear ..... chuck jaws can rock in the slots.....OK ,regrind the jaws .....still rocking in the slots......how can I fix the slots without buying new chucks ,because I cant afford them!.....Answer----With great difficulty!

 

[idacal]

this chuck is an 18" 4 jaw and if it slips there is even markings on the bar stock all the way around and just for more kicks and giggles I stuck a part between centers and got the same results I have been talking about here.
Im still kind of interested in a universal id od grinder just to add to what I have for machinery projects, if the price was right. definitely want a universal though.

 

[texasgeartrain]

with the 2x4 test im only getting .0005-.001 and thats with a lot of pressure

After reading this I checked my 61 Series with a 2x4 as well using a .0001" indicator. I might be getting a single .0001", but I might be ever so slightly rolling spindle to make needle jump.

I was thinking with taper bearings adjusted it should be zero. Unless you think your wear on outside of race is enough to have movement inside the bore. If so, I might use a thin film bearing retainer on chuck side race, as the endplay or preload adjustment is opposite chuck side. If that is indeed the reason you have .0005 to .001" anyway. Getting the race out after using retaining compound might not be as fun in the future, but it wont move or spin when you use it.

The retaining compound I use is Loctite 620:
Amazon.com: Loctite 555338 620 High Temperature Bearing Mount Bottle, 36-Milliliter: Automotive

Not sure if you can afford downtime with your lathe, but for the cost of buying another, and having question marks on it. . .well you could probably put the money into yours and rebuild it a bit, then have a know high quality machine. Or maybe buy a reasonable cost lathe and rebuild yours at your leisure.

If you can do shipping from OK, I think you could get a nice deal on this Powerturn, contact cole2534, he recently got it, but now needs the floorspace:
I joined the heavy iron club, 24x126 Powerturn

With some projects cleared, I started getting back on my Series 61 a couple weeks ago. Doing some prepping right now, but I plan on going the full monty with it. Addressing ways, scraping, aligning etc. I already have a thread on the machine, but I'm going to start another for the rebuild in the Monarch section. Gonna give a shot to some of the ideas we discussed in one of your threads:

monarch 60 series ideas

 

[michiganbuck]

We are curious to learn the findings and know the elements causing the problem.


word removed/changed /deleted /replaced/ deemed wrong/ out of reality/ unacceptal -> anxious

 

[Milland]

We are anxious to learn the findings and know the elements causing the problem.

I'm more curious than anxious. If your anxiety should last more than six hours, consult your doctor.

 

[99Panhard]

I hesitate to comment because so many folks here know a lot more than I do but my 100-year-old flat belt Sidney will hold .001 if I am careful...it sounds to me as if there is something drastically wrong with your lathe or - perhaps it is really worn out. A grinder will not cure that. I wouldn't mind having one myself but space, the learning curve to operate it well, and the fact that I rarely would need it, make that unrealistic.

I'd try to fix the lathe - if it can't be fixed, replace it. Taking .020 off with a grinder to get a good finish is WAY too much. Of course I've no idea what materials you are working with but I've found that 99% of my finish problems can be solved by grinding a different tool and going slow...I confess I"m never in a hurry but a grinder will not speed operations up.

 

[SIP6A]

Your link goes to a mounted grinding point in the $200+ range. Is that correct?

That's for a package of 25

 

[michiganbuck]

That's for a package of 25

Not any of these but some used ones. But there is one package that may be OK
https://www.ebay.com/sch/i.html?_fr...57.m570.l1313&_nkw=norton+60*+point+&_sacat=0

True Norton center laps area fine grit(80) and a very hard bond so they just lap (not grind)and last a long time holding their shape.
Norton Center Lap Mounted Grinding Points - Norton Abrasives - Bonded Abrasives - Norton Abrasives - Shop Manufacturers

1" x 2" Mounted Point 60 Degree (5 Mounted Points) A80-VVM Norton | eBay

Doing a close grinding repair job one would have to move the centers back to near dead on..These Norton center laps would be used to restore the original center position with a center lap machine, or heavy hand on the part as it sat between a dead one end and a center lap at the other end.

Here is the center lap machine but this one having the steady guide fixture missing.
EX-CELL-O 74 Center Lapping Machine, 2HP, Lap, Excello Vertical Lapper, 10"x36" | eBay

 

[idacal]

I think i found part of my problems i kept mess8 g with saddle finally got frustrated and for break started checking oilers in the head stock and quick change. Found out the little oil pump on the quick change isnt working any more not sure if it has since i got the lathe gears still look okay enough spray gets in there . Popped off the lid and the main oil pump arm had broken where it ran in the ecentric ring behind the big gear. We had heard a noise change a few months back but then it quit. Lathe hasnt been run much since then though. For kicks and giggles pulled out the main spindle shaft. Main bearing has been moving on the main shaftbearing not realy spinning just moving and just falls off the shaft I might be using a buch of that locktight i need to think about for a while what to do next.

 

[michiganbuck]

You might run what you are thinking past the lathe guys here. That's not me but here on PM we have some of the sharpest lath guys you can find.

 

[EmanuelGoldstein]

I was thinking with taper bearings adjusted it should be zero.

I tried that once with wheel bearings on the van. Didn't work very well.

MAYBE if you had zero clearance at operating temp it would be okay, but seems like a tenth of clearance would be safer.

 

[texasgeartrain]

I tried that once with wheel bearings on the van. Didn't work very well.

MAYBE if you had zero clearance at operating temp it would be okay, but seems like a tenth of clearance would be safer.

I usually err with caution on that sort of thing myself. But I have seen for a called pre-load on such bearings, be it wheel bearings, trans etc. With the pre-load you're not just taking it to zero, you're going a little tighter once zero is reached.

My personal trick is to go to zero and back off just the slightest C hair, while I'm shocking the housing with a hammer to make sure its seated. Never torched a bearing that way, and have good results/performance.

 

[idacal]

I ran a tophead bearing to tight didn't realize it. the shop that had done the work were a bit careless. its only 100 rpm what could happen right? it will wear in, haha, well it had a internal lube line that didn't get hooked also. once it friction welded itself together it took out a several thousand dollar shaft and 3 weeks of time to get a new one. I can screw things up that bad myself, no reason to pay someone to do that for me. but monarch lathes seem to be preloaded but I haven't ever been able to find a preload spec of some sort. with as much stuff as is moving, hard too believe it would be a foot pound rotating spec would it be a shaft protrusion spec? or real old school so much time at this rpm to this temp