Toolpost Grinder

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Brian Rupnow

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I am considering buying a toolpost grinder from Little Machine shop. The site doesn't give a lot of information about them, and I have never used one before. It says that to use them you must remove the compound rest from your lathe. If you do that, how could you grind anything on a taper? It says that they will fit a C6 or a SC6 lathe, which means very little to me because I have a BusyBee B2227L lathe and I don't know anything about the numbers they refer to on the website. Does anyone out there own a grinder like this? How useful is it. How do you grind a taper with it. they offer a number of different grades of grinding wheels for it. What grades of grinding wheel would you recommend. Can it grind 1018-1020 mild steel, or only hardened steel. Are there any good book available about the care and feeding of tool[post grinders? Any help would be greatly appreciated.---Brian
http://littlemachineshop.com/products/product_view.php?ProductID=4671&category=
 

Dave

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Brian I have one . I am in Oakville , On. I have all the wheels for this unit. Grinding on the lathe is easy as the unit is setup with the taper side running parallel to the axis of the Lathe on centers and the grinding wheel is at the center line , you may have to add add a spacer to adjust for you height .If you would like to try mine let me know. callerdoit@yahoo.com
 

Brian Rupnow

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I guess maybe the second part of my question should be, does anybody sell a toolpost grinder that mounts to (wait for it----The TOOL POST!!!) That would seem t me to have a lot more versatility. (My toolpost is an AXA quick change style.)
 

cfellows

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Brian, I used to have a small Dumore tool post grinder and never found it useful for any of my projects. I finally gave it away to another member of HMEM.

I would be the first to admit that I'm totally inexperienced with tool post grinding and I would certainly hope you get some feedback from more experienced users, but I could never get a satisfactory finish with it.

What kind of application do you have for a tool post grinder?

Chuck
 

MachineTom

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I've used my TP grinders quite a bit before the MG12 arrived. And still use one on work that can't be done on the Myford.

Grinders are for taking off less than.001 per pass, which can be tough when just a bit of a turn is .001. there is a trick for that which is to set compound at 60° from the crossfeed axis, and feed with the compound dial, which would be feeding .0005 for each .001 of the dial.

The small wheels on the littlest grinders like mod 14 Dumore do wear rather quick, so frequent dressing is needed. A diamond dresser is best and the finish of the work will show it.

Another thing is the grit goes everywhere, so first you need to cover all sliding surfaces, then after use you need to clean everything twice being sure no grit is left to wear the saddle, bed crosslide compound, gears tailstock etc. That will take 4 times longer than using the grinder.

Thinks I've done with a TP grinder, cleaned up galled MT tapers, finish cut on turned down drill shanks, finish ground crankshaft for my Corliss build, ground the jaws on several chucks, worked so items that were to large for the OD grinder to swing.

The most common grinder around which I owned as well is a Mod 14 Dumore, a 1/14HP and a 2" wheel, Barely enough power for the wheel, better for internal grinding, with mounted wheels, sold that and bought a Themac 1/2hp 4 " wheel, now that grinder has power, and a larger selection of wheels.

A little grinder on a little lathe, may not be that useful as it takes a lot of the small space, the small wheel gives little standoff from the work, and the drive end of the spindle interferes with the tailstock.Which is often needed to support the work.
 

GWRdriver

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I have one of the little Dumore 14 TP grinders. It was virtually new but it came to me missing belts and wheels. I found belts but after a little searching Dumore was the only source I could find for wheels, and as I recall they were very costly. Since at that time TP grinding wasn't a priority I stopped searching, but now several grinding jobs are on the horizon for my present project and I'll need wheels. So where (aside from Dumore) does one find good quality 2"-3" X 1/4" x 1/4" wheels?
 

Brian Rupnow

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Chuck--I'm not even sure I need a toolpost grinder. It's just that I have a couple of weeks of design work and thought I might buy something for my machine shop as a present to myself from myself. I'm afraid that if I bought a toolpost grinder it might be one of those $200 accessories that looks kind of neat but never gets used.---Brian
 

GWRdriver

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I'm afraid that if I bought a toolpost grinder it might be one of those $200 accessories that looks kind of neat but never gets used.---Brian
More truth to that than you know . . . to make it more truthful we should probably change the $200 to a $500. :eek:
 

cfellows

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Brian, you might consider one of the following if you don't already have one...

Quick Change Tool Post.

2" x 48" Belt Grinder.

Chuck
 

Brian Rupnow

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I have both Chuck. I have a 1" belt grinder and a 4" belt grinder and an AXA toolpost.
 

goldstar31

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At best, it's nigh impossible answer to give a simple answer. It's a huge subject and goes back to something like a clockwork tool apparently in the Dental Museum of the Royal College of Surgeons in Edinburgh. Or so my wife assures me.
The problem of present grinders and the ones that go on the top of lathes goes back to Ian Bradley's book the Grinding Machine where he describes one on the small lathe and goes on to describe all sorts of devices such as dental stuff, a grinder made by old Mr G P Potts( I've two) and his design.
Again, the late Jack Radford published his very similar device. Both books are still available and worth a read.
My discovery was a Bosch wood router. I bought one and found that it was actually a tool post grinder and I converted it back. It takes a 43mm collar which takes a normal electric drill as well.
So it is all very useful- and cheap enough.
Sadly, nothing is a win win situation!
In all of these things is a bug called axial load and whether you are sitting in the dentists chair or grinding metal, bearings wear and have to be replaced.

One day my wife will usher - a good word for Edinburgh- into the place to see the clockwork variety. Maybe her cap and gown in (v)ermin(e) are still at the cleaners.

So at Chinese prices for routers, who really cares?

Norman
 

dieselpilot

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In all of these things is a bug called axial load and whether you are sitting in the dentists chair or grinding metal, bearings wear and have to be replaced.
This is why a good grinder or spindle uses angular contact or tapered roller bearings. There is no easy way out. And it you want a good finish, super precision spindle bearings are in order. That's why a spindle or TP grinder cost so much.

I wonder what sort of bearings you get for $200 in that Seig or whoever makes it?
 

GWRdriver

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This is why a good grinder or spindle uses angular contact or tapered roller bearings.
An old hand at the oldest machine shop in my area told me once that the old toolroom grinders wouldn't use new machines with rolling (ball, etc) bearings if they could help it. They claimed they could see the bearing "tracks" left in the work. They preferred the older plain bearing machines and they felt the same way about lathes.
 

MachineTom

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While that may have been true in 1932, It does not hold true today.
 

jkimberln

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I made my own TPG back when I was restoring motorcycles and needed one to grind the shafts on rocker box rockers. I had to reach in past the arms on the rockers which stuck out about 2 3/4". Thus, I needed a 7" dia grind stone. Nothing commercial was available. I used a timing belt drive and two pulleys. The spindle had axial contact bearings on the head and a ball on the tail end plus nuts for adjusting the preload. I had seals on each end and filled the inside of the spindle casing with oil. It worked well for something that took a few hours to build.

A TPG is something you need about once every five years or so. But is absolutely indispensable for a few jobs.

Mine has a 3 phase motor that I control with a VFD. So I can get variable speeds. I repurposed the head a couple times and made it into a cam grinder and crank grinder for small IC models.

JerryK
 

GWRdriver

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While that may have been true in 1932, It does not hold true today.
No, and I wouldn't suggest that it should.
A TPG is something you need about once every five years or so. But is absolutely indispensable for a few jobs.- jerryK
Jerry, that's about my experience. I also think a TPG (or surface grinder) can present the temptation to start grinding things which have no need of grinding, just grinding for its own sake. Whether that is, or isn't, a good thing I can't judge for anyone else. Personally I've made it through many years without a TPG and I'm none the worse for it, but since I now have one, and I have a set of locomotive crankpins in my near future, I'd like to get mine cranked up.
 

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