Thread: Am I mad

Hi Welder, first answer, Carefully, as for tips I ALWAYS put a single layer of newspaper on the magnetic chuck under the work. this stops any scratches appearing on the chuck & probably increases the grip of the chuck. It certainly doesn't affect the holding power. I use a short (100 - 125mm) piece of 20mm by 20mm aluminum angle on the edge of the chuck to align the work to the direction of travel, this keeps the grinding marks parallel to the work edge. Always use coolant, silicosis is not nice. Be careful when grinding small parts that don't span a few poles, use a backup piece that has a large surface area (but lower than the job) to butt against the work to prevent the wheel sending the job into orbit. Be careful with hands & fingers when the wheel is rotating, I know of one person who went to wipe something away & there was insufficient clearance, OUCH (The wheel didn't even slow down.) Other than that it is just commonsense, keep the wheel dressed, take LIGHT cuts be careful that there is not a high point on the work that can come under the wheel & jam it.
Hope that helps,
tinkera

Cheers the machine doesn't have coolant will this be an issue ?

Hi Welder, Probably. Even with light cuts, small work can heat up significantly & this will definitely expand the job & that means that it will cut deeper, & therefor generate more heat & very quickly could either jam or burst the wheel. Also, the wheel particles are not safe to breath. I would consider that coolant is a must, (be interesting to have others comment.) I don't use my grinder a lot but use coolant. I visited a friendly (big) toolmaking concern & was given some (about 1 litre) of coolant that is mixed 5% with water, so it will last for awhile. There is a post re home made coolant, I would think that a grinder is much more tolerant than other machine tools as lubrication is not required, just something that has good heat transfer properties, doesn't cause either flight or ordinary rust & doesn't turn rancid.
tinkera

Well I have soluble cutting oil which is what we use one the cylindrical grinder at work. If it's an issue I can rig up a spray mister which I am using on the bandsaw Althought the machine was "designed" for dry grinding.

Coolant in a spray bottle is all you will need, if you want to use any at all...

Hi Andre,

No you're not mad, you've got yourself a handy addition to the workshop. I'd like to see some pictures and a bit more about what came with it. Did you get a mag chuck? Dresser? Wheel balancer?

Run coolant if you can. Spray bottle is fine.

Ray

Mad.... I don't think that is even vaguely relevant.

The *only* 2 relevant considerations, IMO, are space and money when it comes to getting more tools.

PDW

I am picking it up tomorrow I does have a mag chuck not sure what else. It's 3 phase so I will have to try this VFD thing.

after forking out $1500 for a Taiwanese there is a Churchill for half that Churchill Surface Grinder 8in X 20in | eBay

Andre
Your machine will find a lot of use.
Regarding Wet or Dry Grinding as mentioned above a spray will work fine.
Dry grinding also works if you take light cuts, I mentioned in the PM to you... max .002" depth of cut & fast table reciprocating speed, this makes the grinding wheel act "softer" & cuts cooler.
My first choice is a White or Ruby vitrified Alum Ox 46 "K" bond.... I do also very occasionally use an Alum Ox 46 "H" bond for HSS grinding. or hardened chrome alloy steels.
The H bond is a softer bond than the 46 K.
Coarse (fast cross speed) of the diamond dresser will also make the wheel act & grind cooler, this will come with trial.
Dont be tempted to use fine grade wheels, unless for precision sharp corner grinding up to say a shoulder.
The 46 K wheel will satisfy nearly all surface grinding
The wheel should last you for a long time if you true & diamond dress it carefully. You will notice as the wheel diameter reduces over time the grinding action of the wheel will be like using a softer bond strength. it will cut cooler & the grains will fracture more readily (Lower wheel surface speed)
Cross feed rate..... I index at the end of each reciprocation about .040" this is using a 7" dia by 1/2" wide wheel.
Its important when first starting to surface grind the workpice, to carefuly bring the wheel head down on the workpiece edge so that contact is made on say, the first 1/16th" of the wheel width... not the full wheel width.
Then the down feed to make contact, should be slow & gentle until light sparks appear, .0001" then the cut depth of say a .001" to .002" max is made. Important that you are reciprocating the table while this is done to ensure you are picking up the high spots on the workpiece.
These are wonderful machines, & as mentioned if you are up in my nek of the woods just give me a call & we can run my machine & go through a few notes.
regards
Bruce

Originally Posted by welder

after forking out $1500 for a Taiwanese there is a Churchill for half that Churchill Surface Grinder 8in X 20in | eBay

MUST....... RESIST...... URGE...... TO...... PRESS...... BIN....... BUTTON!!!!!!!

PDW

It comes with a granite surface plate with tee slots and a bench micrometer.

Nice one Andre. You'll wonder how you did without it.

As far as learning goes Bruce looks like he may have you covered. I found very little online info on using a SG, the tool and die guy has some good vids but thats about it. I have put some video's up of some projects that have a fair bit of grinding in them and cover what i have found so far....but i'm a long way from being an expert. https://www.youtube.com/user/ueee84 The mag block and collet block both include SG time.

Bruce, i would have though .002" would have been a bit of a big cut for a smaller machine, i find if i go much more than that the wheel (38A 46k) tends to wear quickly.

Ew

Originally Posted by PDW

MUST....... RESIST...... URGE...... TO...... PRESS...... BIN....... BUTTON!!!!!!!

PDW

After Andre forwarded the picture of the Churchill Surface Grinder, I could not stop thinking about it.
My Churchill is practically identical to the one for sale. I got hooked on it because its the same unit I used as an Apprentice at AWA ashfield in the Toolroom 1958 to 1961 era/
My machine, came to Australia new, from England in Aug 1950.
Its seen a bit of work over its life. I purchased it in the used condition 20 or so years ago for $2000
The machine on E bay for sale looks pretty good at that price of $775 its had a coat of paint & someone has rigged up the coolant flow in the wrong direction (against wheel rotation) but all in all it looks good.
These machines were built in Manchester England around WW2 & thereafter & are solid, very solid, & bulletproof.
I would not hesitate on purchasing, but then it would ne nice to inspect longitudinal slides & main grinding head bearing.
The main bearing has a gravity fed oil pressure system to self adjust the bearing with an air relief valve.
A long lasting arrangement.
Good pommie engineering !!!!
regards
Bruce