Mini grinder.

Terry Keeley · Feb 19, 2019

Not strictly boating related but it's been kinda slow around here anyway.

I had to true up the spindle on my Clausing mill and used my NSK grinder mounted to my Super 11 to do it. I'll use the same set up to O/D grind some RSA-431 pistons and eventually re-chromed liners.

Jim Allen · Feb 19, 2019

Cool beans Terry. I use my Themac tool post grinder to do jobs like this. I designed the mount so that it can be used on the OD grinder to do ID grinding work. I have re-ground the 5-C collet seat in the spindle adaptor for zero runout on my Super 11. The fixture mounted to the machined face plate has a precision "V" block mounted for grinding any crank pin hole square to any crankshaft with zero runout. I can also mount the Yuasa jig grinder directly to the compound for ID grinding. This tool uses an air turbine to turn it's spindle 120,000 RPM with 80 lbs of air.

JA

Andy Brown · Feb 20, 2019

Awesome work guys!

Who is a good supplier of grinding stones?

Jim Allen · Feb 20, 2019

Wow Andy! What kind is going to be determined by what is being ground. Sometimes it becomes cheaper to make your own from used up wheels from larger size grinders. For example the small diameter ID grinding stones used for chrome are made from larger size wheels. These wheels are typically approximately 1.000" in diameter or smaller. You can drill a mounting hole, rough cut the outside in a band saw, glue on protective papers & dress after mounting on a mandrel that mounts the stone. Large size grinding stones, 6" to 8" are readily available in many compositions, grits & thicknesses at many metal working suppliers.

Jim Allen

TomGracey · Feb 20, 2019

NICE as a retired Machinist CNC shop owner always enjoy anything to due with machining Nice looking machinery . Only thing U need is a DRO set up so U can ditch all the Dial Indicators

That's 1 nice TPG

Jim Allen · Feb 20, 2019

TomGracey said:
NICE as a retired Machinist CNC shop owner always enjoy anything to due with machining Nice looking machinery . Only thing U need is a DRO set up so U can ditch all the Dial Indicators

DRO's can only read to the whatever resolution is built into the system. Precision indicators can detect any amount of movement, especially if the increments on the indicator are .00005!

Retired Tool Maker

_625%20bore%20barrel%20carburetor%20on%20QD%20002.jpg

TomGracey · Feb 20, 2019

Jim Allen said:
DRO's can only read to the whatever resolution is built into the system. Precision indicators can detect any amount of movement, especially if the increments on the indicator are .00005!

Retired Tool Maker

View attachment 99924

mine read to + -.00001 the spindle bearings are not that accurate on a mini lathe

Terry Keeley · Feb 20, 2019

Andy Brown said:
Awesome work guys!

Who is a good supplier of grinding stones?

Dumore sell a wide variety of wheels but they're probably all made by Norton.

https://www.dumoretools.com/grinding-wheels/series-14?osCsid=tue0quku1bt9j0shopb35417a1

I'm trying to find out what I need to grind the 30% Si RSA-431, I sent http://www.rsp-technology.com/ a note but they didn't know. It's probably going to be some kind of silicone carbide.

Terry Keeley · Feb 20, 2019

TomGracey said:
NICE as a retired Machinist CNC shop owner always enjoy anything to due with machining Nice looking machinery . Only thing U need is a DRO set up so U can ditch all the Dial Indicators

That's 1 nice TPG

Just got a nice DRO setup for my mill, 1 um magnetic scales, can't wait to set it up!

Jim Allen · Feb 20, 2019

Terry Keeley said:
Dumore sell a wide variety of wheels but they're probably all made by Norton.

https://www.dumoretools.com/grinding-wheels/series-14?osCsid=tue0quku1bt9j0shopb35417a1

I'm trying to find out what I need to grind the 30% Si RSA-431, I sent http://www.rsp-technology.com/ a note but they didn't know. It's probably going to be some kind of silicone carbide.

Terry,

I looked up the Dumore wheels & they are in 1/4" increments with the smallest size at 1/2". There doesn't seem to be any information about what abrasive types are available. When grinding small ID's, less the 1.000, you will want to use the largest diameter wheel possible which will fit in the bore being ground. Grinding chrome is best done with aluminum oxide wheels, 100 to 120 grit, lubricated with "used" sulfur based oil; oil that has previously been used to grind chrome. For diameters less than 1.000", the wheel should be turning at 25,000 to 35,000 RPM. The wheel should be as wide as possible & this is why I suggested that you make your own wheels from scrap full size grinder wheels. Norton has many different types of wheels & they are readily available from Manhattan Tool Supply. They also come in many different widths.

Jim Allen

TomGracey · Feb 20, 2019

Terry Keeley said:
Just got a nice DRO setup for my mill, 1 um magnetic scales, can't wait to set it up!

Linear scales are more accurate but for the home DIY machinist there just fine They make life so nice ,no counting feed screw handle turns if U have mid priced model with a bunch of features U can to so many different operations Like .the 1 I have on my mid sized CNC mill absolute/incremental coordinate display, arc function, line of holes function, angles cuts function, 199 user defined datum points, centering/cutter offset, double sealed scales, inches/millimeters, calculator with trig functions..

Have fun with it

Screen Shot 2019-02-20 at 9.47.21 AM.png

TomGracey · Feb 20, 2019

Jim Allen said:
Terry,

I looked up the Dumore wheels & they are in 1/4" increments with the smallest size at 1/2". There doesn't seem to be any information about what abrasive types are available. When grinding small ID's, less the 1.000, you will want to use the largest diameter wheel possible which will fit in the bore being ground. Grinding chrome is best done with aluminum oxide wheels, 100 to 120 grit, lubricated with "used" sulfur based oil; oil that has previously been used to grind chrome. For diameters less than 1.000", the wheel should be turning at 25,000 to 35,000 RPM. The wheel should be as wide as possible & this is why I suggested that you make your own wheels from scrap full size grinder wheels. Norton has many different types of wheels & they are readily available from Manhattan Tool Supply. They also come in many different widths.

Jim Allen

View attachment 99935

View attachment 99936

Nice cylinder grinding fixture Jim I can see the T&D maker skills

Jim Allen · Feb 20, 2019

Terry Keeley said:
Just got a nice DRO setup for my mill, 1 um magnetic scales, can't wait to set it up!

TomGracey said:
Linear scales are more accurate but for the home DIY machinist there just fine They make life so nice ,no counting feed screw handle turns if U have mid priced model with a bunch of features U can to so many different operations Like .the 1 I have on my mid sized CNC mill absolute/incremental coordinate display, arc function, line of holes function, angles cuts function, 199 user defined datum points, centering/cutter offset, double sealed scales, inches/millimeters, calculator with trig functions..

Have fun with it

View attachment 99934

I need a little more accuracy Tom, therefore I use a .00005" Heidenhain digital readout that has a .00005" resolution. I can set up a .00005" indicator & move the table without the digital readout changing it's reading. This is why I say a precision indicator "NEVER LIES"!

Jim Allen

Jim Allen · Feb 20, 2019

Terry,

Get some MB-30-5 Sunnen Honing oil for grinding chrome. We also use it in the Sunnen honing machine when honing chrome.

JA

Terry Keeley · Feb 20, 2019

Nice work as always Jim, it might be a while until I get to grinding chrome liners again but the pistons will be fairly soon since I'm cracking the stock CMB 67 units.

I think the Dumore wheels are all Norton 32A if they are AlOx.

I want to try some very low taper liners that are ground very round and with the same kind of surface finish you got. I think I'll to grind them right in the case they'll be run in.

Terry Keeley · Feb 20, 2019

TomGracey said:
Linear scales are more accurate but for the home DIY machinist there just fine They make life so nice ,no counting feed screw handle turns if U have mid priced model with a bunch of features U can to so many different operations Like .the 1 I have on my mid sized CNC mill absolute/incremental coordinate display, arc function, line of holes function, angles cuts function, 199 user defined datum points, centering/cutter offset, double sealed scales, inches/millimeters, calculator with trig functions..

Have fun with it

View attachment 99934

Here's the unit I got: http://www.electronicaems.com/EL400.php

With these scales: http://www.electronicaems.com/Magna-Slim.php

Alan Elzer · Feb 20, 2019

Thnx GUY'S great info... question what type of stones are used for this application?

Sent from my SM-N920V using Tapatalk

TomGracey · Feb 21, 2019

Terry Keeley said:
Here's the unit I got: http://www.electronicaems.com/EL400.php

With these scales: http://www.electronicaems.com/Magna-Slim.php

Terry Keeley · Feb 21, 2019

Alan Elzer said:
Thnx GUY'S great info... question what type of stones are used for this application?

Sent from my SM-N920V using Tapatalk

AlOx...

Jim Allen · Feb 21, 2019

Alan Elzer said:
Thnx GUY'S great info... question what type of stones are used for this application?

Sent from my SM-N920V using Tapatalk

Alan,

If you are grinding hard industrial chrome with an OD-ID grinder, white Aluminum oxide, 100 to 120 grit, running at 20,000 to 35,000 RPM, using the previously mentioned Sunnen Honing oil will give spectacular results in a short period of time. Select a wheel with an OD that is very close to the ID of the piece being ground. Do not use a narrow width wheel (less than 1/2" wide) & do not allow the wheel to grind off the ends of the piece! You can achieve the same finish with honing, but it will take longer. Honing will require gray Aluminum oxide stones of 63, 81 and 93 grit. Establishing the correct amount of back & forth motion as the hone rotates will take some practice to achieve the same finish as grinding.

Be cognizant of what method is used to hold any cylinder to be ground or honed!! A cylinder should never be clamped on its OD for either of these operations. The holding fixture used on the honing machine does not clamp on the OD of the cylinder. Notice the center set screw that prevents the PVC from clamping on the cylinder's OD. The white nylon screw prevents the cylinder from rotating when it is slip fitted into the PVC holding fixture.

Jim Allen

Mini grinder.

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