What's new
What's new

Whats a tool post grinder for?

Michaeljp86

Aluminum
Joined
Sep 19, 2012
Location
SW Michigan
I was wondering if anyone could tell me what tool post grinders are used for on a lathe. Mr. Pete on youtube used one to grind a dead center once. Do you need a grinder for that because they are hardened? What other uses does a toolpost grinder have?
 
You use a toopost grinder to turn your lathe into a sort of universal grinder. You can grind shafts, rings etc. In my experience they're OK but not as good as the real thing. Regards Tyrone
 
They are used to turn your lathe into a piece of scrap. The abrasive particles released will find their way into every nook and cranny. You must take every precaution to catch these particles during use of a tool post grinder. Use softer dead centers and dress up with a tool bit.
 
If you have not already done so, I'd suggest you get a copy of South Bend Lathe's immortal work: "How to Run a Lathe". It will answer a lot of questions you may have, including the uses of a toolpost grinder.

I agree with all that John Oder, Tommy1010, and Tyrone have said about toolpost grinders. The toolpost grinder enables a person to finish grind hardened parts to final diameter. It is NOT for taking off huge amounts of material, but a matter of a few thousandths. Aside from grinding the headstock center in place, a toolpost grinder would find use in finish grinding hardened parts such as a shaft journal to run inside a needle bearing, or perhaps a hardened mandrel. Another use would be the grinding of engine valve seating surfaces. Most engine valves (as used in automobile, motorcycle, tractor, or diesel engines) have hard seating surfaces on the "valve head". These surfaces have to be finished to a series of conical angles, to seat correctly in the valve seats. engine rebuilders and service garages often have a small precision grinding machine built just for this purpose. In bygone days, shops working on various engines did not have the money for the valve grinder, so made do with a lathe. The lathe saw service turning the commutators on starters and generators. Equipped with a "mica undercutter", it could finish the reconditioning of commutators. as a lathe, it made odd parts such as valve guide bushings, and many other odd parts. Equipped with a toolpost grinder, the lathe could grind engine valves to the correct angles.

Toolpost grinders are handy to have, but the odds of needing one very often are not really high. Mine sits in its box for years at a time.
 
tool post grinder

I was wondering if anyone could tell me what tool post grinders are used for on a lathe. Mr. Pete on youtube used one to grind a dead center once. Do you need a grinder for that because they are hardened? What other uses does a toolpost grinder have?
.
i have used tool post grinders and an adapter to hold a Dewalt die grinder.
.
basically i used to put a mirror type finish on internal pump mixer parts using Cratex rubberized abrasive stones. these stones can do a nice job. normally i only took 0.0005" at a time as i was improving surface finish and not wanting to take a lot of material off.
.
i personally do not think they are any worse for a lathe than someone using 1" strips of emery cloth to polish on a lathe or for that matter a lathe sitting unused rusting away in a garage somewhere.
 
If you have the space, it might be better to spend the money (for a TP grinder) on a good tool & cutter grinder such as a Cincinnati #2 with a good workhead, centers, and some tooling. Except for thread grinding, does just about all a TP grinder will with better rigidity, easier set up, and accomodation for the grit. Plus other uses. Such as tool making and grinding.

smt
 
There is one job for which a lathe tool post grinder is actually the best choice. That is truing the hard jaws on a universal chuck while it is installed on its own lathe. You have to have the proper way to load the jaws during grinding, but you end up with improved accuracy.

Old newspaper is an ideal way cover while grinding. It is safe in that it will not get caught up in rotating parts and effective in that it will not let dust filter through. Cloth is a bad choice for covering ways. Plastic could also get caught in the works.

Larry
 
Lots of good information. A lathe is not designed to be a grinder. A grinder has the slides covered to keep dust off while a lathe deals with bigger chips and depends on wipers, which really don't do the job. I have two toolpost grinders, an old Dumore, which is marginally useful and a Precise which is very good, but I only use either sparingly and only when I have to. When a company I worked for set up a separate R&D operation, they gave us a small South Bend lathe that had been used in the plant to grind carbide glass cutter wheels with a diamond wheel. The monkeys who ran it never covered the ways and the combined dust totally destroyed it. It was just a lump of scrap iron vaguely shaped like a lathe. It took a lot of campaigning, but we finally got a new one.

Bill
 
i finish ground & sharpened fluted several sets of rough & finish chambering reamers w/ a tool post grinder in my crftsmn 12x36 ..
i agree ...think more damage is done w/ regular use of abrasive cloth finishing than one off grinding every few years......very specialized tool.
now that my 1913 leblond T&C grinder is tooled & running , i am tempted to sell the tool post grinder .
..
a soft center in headstock or the 3 jaw is a simple answer to not having a tool post grinder ..
if you need to grind chuck jaws , just strap a 1/8 or more mtr on the compound & attach an adapter for a small stone .
best wishes
doc
 
Tommy nailed it. Toolpost grinder is a real lathe killer. Emery tape can be as well, if you don't wipe your ways down and then oil after use (read: "before moving the carriage, steady rest or tailstock"). If you don't wipe the ways down, harder chips will have the same effect, unless you have tool steel ways like on the late model Monarchs, Sidneys and Pacemakers. Wiping down and oiling is just part of normal lathe practice. Emery tape doesn't spray abrasive particles like a grinder, though.
 

TEmery tape can be as well, if you don't wipe your ways down and then oil after use (read: "before moving the carriage, steady rest or tailstock"). If you don't wipe the ways down, harder chips will have the same effect, unless you have tool steel ways like on the late model Monarchs, Sidneys and Pacemakers. Wiping down and oiling is just part of normal lathe practice. Emery tape doesn't spray abrasive particles like a grinder, though.

imo emery paper contributes all kinds of grit, likely more than grinding. Grinding doesn't spew much grit about EXECPT when DRESSING. If you've ever filtered out of the coolant and examine the fines from grinding it is almost all material removed not grit (again except for dressing)

imo the only way to protect the lathe while using any abrasive is paper towels carefully laid out and held with pot magnets. cloth or plastic is dangerous if there's a snag whereas paper towel will rip.

layout the paper towel as suggested and use emery - look at how much grit falls on the paper towel. As the grit is harder than hardened ways, it will damage them as well - they need as much protecting.

Abrasives and the lathe are something to be avoided....but not everyone has a cylindrical grinder and sometimes a part needs a shine. otoh I agree with Steve Thomas; a small T&CG with motorized head and coolants makes a great light duty cylindrical grindedr and they are not that much money.
 
Have never in my life seen a lathe bed worn down 1/8" from emory tape. I have seen first hand an atlas and a 13" SB worn that much due to toolpost grinding.
 
I bought a Rockwell lathe used in Williamsburg for polishing candle sticks at the Geddy Foundry. It would not cut metal so loose was everything. It had 2 ball bearing dead centers with it,which had been rubbed with abrasive cloth so much you could actually see the ball bearings inside it through an oval opening over 1/8" wide.

I got the lathe very cheap,knowing it was worn out. I recut the bed(which was hardened) on a planer mill. The bed was also discovered to have warped over time.I re cut the cross slide's dovetails,which were worn out. I cut them and tested until the lathe would face dead flat(which I prefer to facing a bit hollow).The tailstock quill would not lock. I put the tailstock in front of the carriage,propelling it with the power feed,gently clamped down,and bored out the hole with a long boring bar held in the chuck,then lapped it. I made a new,oversized quill for it,also making a left hand acme tap to tap the hole in the rear end of the quill. I made a #2 MT hole for it.

The lead screw had to be lowered some to clear the half nuts.

I sold the lathe to a local gunsmith. It's accuracy was better than new. This is an example of a lathe BADLY worn out with abrasive strips. The lathe was not very old,either. I doubt it was more than 10 years old.
 
Your Comment Hit Home

.
i have used tool post grinders and an adapter to hold a Dewalt die grinder.
.
basically i used to put a mirror type finish on internal pump mixer parts using Cratex rubberized abrasive stones. these stones can do a nice job. normally i only took 0.0005" at a time as i was improving surface finish and not wanting to take a lot of material off.
.
i personally do not think they are any worse for a lathe than someone using 1" strips of emery cloth to polish on a lathe or for that matter a lathe sitting unused rusting away in a garage somewhere.

——————-

I recently purchase a brand new lathe for my shop as I was needing to repair hydraulic cylinders and make custom bits for 75 year old tractors. The month I got it in place, tested and all the supporting tools and gear I had some major health issues,. Go figure! I’m hoping to get back to it. I go out and oil it down and keep a heavily waxed oil cloth over it. Nothing more disappointing than a $100,000 machine shop sitting idle.
 
I used a tool post grinder on the outside of this cannon barrel which gave it a really nice uniform smooth finish. This was when I was in high school back in 1973 when I was learning from my dad who was a machinist. I recall that my dad had put pieces of cardboard on the ways to try to protect them from the grit and we did a real good cleaning job afterward. The grinder was homemade with pillow block bearings, a 1/2 HP motor and an 8" wheel. I still have it. I recall another job where I had built up a worn 2" dia. shaft by welding and it was pretty hard. Finished it to size with the grinder. I can only recall a few times of using one in the past 45 years. I refrain from using a tool post grinder because of the potential damage to my lathe and don't like to use them.
 

Attachments

  • Boye & Emmes.jpg
    Boye & Emmes.jpg
    26.2 KB · Views: 52
  • Cannons.jpg
    Cannons.jpg
    47.2 KB · Views: 47
  • Cannons6.jpg
    Cannons6.jpg
    52.2 KB · Views: 45
  • Cannons4.jpg
    Cannons4.jpg
    95.2 KB · Views: 46
I used a tool post grinder on a 14" Clausing to grind threads on an injection mold core.
R&D environment for single cavity sample mold. Actually worked out pretty well.

Custom bottle cap thread required the wheel dressed to odd angles.
Half nut remained engaged.
Slow feed by pulling the chuck by hand allowed for precise stopping point.
Used power to reset for next pass after retracting the cross slide.

Actually covered everything with rags, but after reading the previous comments, paper or cardboard might have been better. Try to avoid oil or water so as not to end up with 'lapping compound' all over the place.

This was in the late 70's. Not much NC or CNC available for smaller shops.
The multi-cavity production mold had the threads farmed out to a shop with a J&L thread grinder.
Loved those days tool-making using creative set-ups.
 








 
Back
Top