how do i mount a 20 mm bearing ball on the sg to make a flat? the only solution i can think of is to make a fixture where it would be held down by three screws. not sure how much i could take off that way, looking to do around a third of the diameter.
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grinding a ball
- Thread starter dian
- Start date
- Replies 19
- Views 3,580
rustytool
Stainless
- Joined
- Oct 27, 2010
- Location
- Moscow,Idaho,USA
I've seen it done by putting the ball in a 5c collet with a collet stop.
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
Having anything with screw holes base ( I would use my angle plate that has screw holes.) Make a cross bar with perhaps a 3/4 or 5/8 hole depending on the thickness of the cross bar with having a couple screw holes that match the threaded holes on the base.. Once ball is mounted touch the top and take small down feed grind passes with full wheel..Pat shoul be very solid held that way. How wide a flat do you wish?
Yes you could incremental cross grind but I would likely not
Oh you down feed only on the grind side.
Use perhaps a 46 wheel.
Yes you could incremental cross grind but I would likely not
Oh you down feed only on the grind side.
Use perhaps a 46 wheel.
James Lederer
Hot Rolled
- Joined
- Mar 19, 2012
- Location
- Southern Wisconsin
It's a hardened ball, right? Hold it in any vise you can stick to the mag chuck and have at it until your flat is as big as you want. Oh, yeah. Make sure the jaws are perpindicular to the wheel. If you need to, use a couple pieces of aluminum with centers drilled in them to give a larger contact patch to prevent rotation of the ball.
D Dubeau
Hot Rolled
- Joined
- Jan 29, 2007
- Location
- Ontario, Canada
Drill/ream a 20mm though hole (or bore, whatever is easier) in an aluminum block (whatever scrap you have). Now make a saw cut into it so that you can squeeze it in a grinding vise and hold the ball.
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
Roughly a 7/8 ball ground down to about 9/16 so yes the hold is above half..so any simple hold will do.
Illinoyance
Stainless
- Joined
- Aug 24, 2015
First set it up in the lathe to remove the bulk of the material. I did this in a 3 jaw chuck using sheet aluminum to pad the jaws. Carbide insert at high surface speed and fairly light cuts. If you have a small 3 or 4 jaw chuck you could use that to fixture the ball on the grinder.
AARONT
Stainless
- Joined
- Feb 19, 2013
- Location
- Madison, WI
This....................
Mark Rand
Diamond
- Joined
- Jul 9, 2007
- Location
- UK Rugby Warwickshire
If you're using ER collets, get an ER collet block like these. Then you can mount it on the magnetic chuck. Use a magnetic transfer block to help if you think it needs to be held more firmly. I use a magnetic V block placed vertically on the chuck to hold a square collet block.
Obviously, choose one that fits the ER collets you have. It will come in useful for other jobs.
swatkins
Titanium
- Joined
- Jul 24, 2011
- Location
- Navasota / Whitehall Texas
D Dubeau
Hot Rolled
- Joined
- Jan 29, 2007
- Location
- Ontario, Canada
If it's for what I think it is (a half ball for providing single point contact in a mill vise), then it really doesn't matter much at all. As long as one side is "flat" and the opposite side is "round". Vise grips, and a belt sander would get you there too.......
ballen
Diamond
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
I use a 28mm ball bearing for this, and the flat is about 10mm in diameter. So I also don't think you need a half-ball, you only need to grind off enough that the flat face doesn't indent the vise jaws.
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
Using James's idea but simply using a couple nuts as the vice holder.. perhaps 1/2" or what ever makes the need.
Last edited:
Illinoyance
Stainless
- Joined
- Aug 24, 2015
If you are using the ball for clamping you can do it all on the lathe. No need to grind.
Toms Wheels
Titanium
- Joined
- Dec 30, 2005
- Location
- Jersey Shore
If for use in a milling vise, my 1.250 ball only has a .375 flat spot and works fine. The flat is against the work, the round against the jaws, otherwise dents appear on anything that is not hardened.
A 3" vise with a double set of Vee grooves has worked every time for holding the ball when grinding.
A 3" vise with a double set of Vee grooves has worked every time for holding the ball when grinding.
CarbideBob
Diamond
- Joined
- Jan 14, 2007
- Location
- Flushing/Flint, Michigan
A grinding vise.
They usually have a notch in the clamp side which will work just fine for this job.
Block under the ball for support and alignment if you want two parallel flats and yes I use my gage blocks for this.
Don't over complicate this.
Bob
They usually have a notch in the clamp side which will work just fine for this job.
Block under the ball for support and alignment if you want two parallel flats and yes I use my gage blocks for this.
Don't over complicate this.
Bob
ballen
Diamond
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
I think that is backwards, you want the flat against the vice jaws and the round side on the work. The dent helps to lock the work and will typically be milled off later in the squaring up See this quote from a respected book on machine shop practice.
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