# Just another Tool Post Grinder



## Brucepts (Dec 21, 2021)

Been looking at all sorts of small tool post grinder ideas for my 1440 lathe and came up with my own take on what might work for my applications. 

To be honest I'm not even sure what I will be using it for but decided to build something anyways. 

Started with a BXA 1" boring bar holder, ER20 100L arbor, 20x32x7 bearings (started with ABEC 1 but upgraded to ABEC 3 once the concept worked) and a 775 DC motor. Bored the holder for the bearings, machined my own round belt pulley set to fit 4mm belt. Working on a design now for dressing tool holder. 

Not sure how the 775 motor will work out, I was impressed with how well it has done in my testing so far. I'm looking at an upgrade for that in the future though.

This is a work in progress and I appreciate all those who have posted their own designs for others to look at, I'm sure you will find your ideas alive in other's projects!


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## Brucepts (Dec 27, 2021)

Added a wheel dresser to the project, shaft is 2 pieces bottom 5/8", top is 3/8" threaded into bottom, stone is 1/8" shaft


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## john.oliver35 (Dec 27, 2021)

Nice work!  I had a question about your spindle build.  How did you mount your bearings?  I see folks line boring spindles like this, and others simply press-fitting into existing bores.  How did you do this one, and what is your assessment of the performance?


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## Brucepts (Dec 28, 2021)

john.oliver35 said:


> Nice work!  I had a question about your spindle build.  How did you mount your bearings?  I see folks line boring spindles like this, and others simply press-fitting into existing bores.  How did you do this one, and what is your assessment of the performance?



My goal was to make a simple tool post grinder that would do simple grinding projects, so keep that in mind with what follows;

I simply setup the boring bar holder in a 4 jaw and bored out the pocket for the bearing to a light press fit in on both ends. This worked out better than I thought it would. I did not want to get into the vertical holes in the holder. Bearing were then pressed in, I installed the spindle with a 20x1mm shim washer on each end and then the pulley. I preloaded the bearings by inserting a threaded rod with nuts to draw the spindle/pulley together so it all spun freely and then tightened the pulley grub screws down.

So far my impressions are this:

Works better than I thought, it's not an "industrial grade" tool post grinder but will suit my needs (not even sure what my needs are) 
ABEC3 bearings made a world of difference.
Motor will need upgraded, once it goes above a certain voltage the brushes become noisy/vibrate

I'm thinking of sealing the vertical holes in the holder so I can run oil or grease on the bearings not sure how long the sealed bearings will last. 
Looking at using a long ER11 collet holder for internal grinding if my needs require that.


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## Brucepts (Dec 28, 2021)

I have zero knowledge in tool post grinding other than what you see here in this picture. The part is an old rusty drill bit that someone had ground down manually. 

This should give you an idea of the surface finish I'm getting with my grinding knowledge level


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## frankly2 (Dec 28, 2021)

I really like the looks and setup, thinking this would work for my needs on my SB 9”. Thanks for your posting the idea ! !


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## woodchucker (Dec 28, 2021)

I don't know if you are familiar with brushless motors for R/C. But you might appreciate the power/speed and quietness. You will have to investigate speed controllers, or program your own, since brushless need to convert D.C. to A.C. and are essentially 3 phase little motors I believe.

Nice build. That size will come in handy for internal grinding too.


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## Brucepts (Jan 7, 2022)

I updated the motor today, over the holiday I got a (what I thought) bargain on a 48vdc 400w brushless spindle motor with, 48v power supply, controller & tach for $103 (there was a $25 discount coupon) off Amazon. The motor had an ER11 collet holder that in the pictures appeared to be removable which is what I was looking for. The one I received had it machined on the motor shaft. At some point I'll probably machine the excess part of the ER11 off the shaft.

I was able to modify my existing motor mount for the new motor and just needed to bore out the motor pulley to fit the larger 15mm shaft. I like the fact it came with the tach so I can set my spindle speeds. It is quiet compared to the other motor and has no issue going up to the motor speed of 12,000rpm's

Hope this project inspires others to build something in their shop!


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## Watchwatch (Jan 7, 2022)

You’ve inspired me. I have a couple three things holding me up. At least 5 projects that need completed, 55hr work weeks, and an aversion to aluminum oxide dust on my lathe.

Does anyone run CBN wheels on a TPG? That would cut way down on the dust.


Sent from my iPhone using Tapatalk


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## woodchucker (Jan 7, 2022)

Watchwatch said:


> You’ve inspired me. I have a couple three things holding me up. At least 5 projects that need completed, 55hr work weeks, and an aversion to aluminum oxide dust on my lathe.
> 
> Does anyone run CBN wheels on a TPG? That would cut way down on the dust.
> 
> ...


there's always towels for your lathe or newspaper I've seen someone use.


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## Watchwatch (Jan 7, 2022)

woodchucker said:


> there's always towels for your lathe or newspaper I've seen someone use.




But what about the chuck? Grit getting in my 6 jaw would keep me up at night!


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## woodchucker (Jan 7, 2022)

Watchwatch said:


> But what about the chuck? Grit getting in my 6 jaw would keep me up at night!
> 
> 
> Sent from my iPhone using Tapatalk


put a bag over it...  she'll never know what happened..    then tape around her.  really there are ways to protect things. put a hole in piece of cardboard, or piece of tyvek and hold it using something.

Or don't , and worry about your equipment, and never venture out to do things that might put grit on your lathe... Don't cut cast iron either.

Look, you can have pristine equip, or you can use it... Take apart the chuck and clean it after..  I use sandpaper / emery  / tool post grinder/ cut cast iron.. I protect my ways, I protect my carriage. I vacuum when done. I wipe with a paper towel a few times.. I oil after, then wipe again hoping that if anything is left, the oil pics it up and so does my fresh paper towel.

BTW I run a file on my lathe... sometimes it cuts, sometimes its so fine its like grit..

just saying.

now if you have a super precision lathe like a 10ee, or rivet or similar then yea, do it on a different lathe.


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## Made in USA (Mar 14, 2022)

Brucepts said:


> Been looking at all sorts of small tool post grinder ideas for my 1440 lathe and came up with my own take on what might work for my applications.
> 
> To be honest I'm not even sure what I will be using it for but decided to build something anyways.
> 
> ...


Nice job, this is something I have been wanting to buy. Maybe after seeing your grinder I think you gave me the feeling I can try it! 
Thanks!


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## Janderso (Mar 18, 2022)

Brucepts said:


> I updated the motor today, over the holiday I got a (what I thought) bargain on a 48vdc 400w brushless spindle motor with, 48v power supply, controller & tach for $103 (there was a $25 discount coupon) off Amazon. The motor had an ER11 collet holder that in the pictures appeared to be removable which is what I was looking for. The one I received had it machined on the motor shaft. At some point I'll probably machine the excess part of the ER11 off the shaft.
> 
> I was able to modify my existing motor mount for the new motor and just needed to bore out the motor pulley to fit the larger 15mm shaft. I like the fact it came with the tach so I can set my spindle speeds. It is quiet compared to the other motor and has no issue going up to the motor speed of 12,000rpm's
> 
> Hope this project inspires others to build something in their shop!


Man, that is really sweet.I want one.


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