surface grinder experience?

[knighty]

anyone have experience with surface grinding ?

I have mincer blades/plates that need sharpening, last two places I use have both closed down and paying postage to send them away rubs me the wrong way

I see plenty of surface grinding machines on ebay or machinery auctions going for £500 is or less, so seams well worth buying one (have 3 phase, so that helps)... but I don't really know what I'm looking at or what I need to buy

here's the blades/plates I need to sharpen

can of coke for scale, plates are 160mm diamiter

kidney plate

plate with 10mm holes

double sided blades

the center boss on the blades fits into the center of the plates

Unger system, so mincer has 3 blades with 2 double sided blades between them all at the same time

have a few other mincers too, but these size ones do most of the work


anyone have any ideas/tips/info ? I don't want to buy the wrong machine

 

[WorkshopChris]

Any machine with the correct amount of travel would probably be ok.
Have you used a surface grinder before, some things to consider.
But just looking at it from the grinding side of things, do you know what type of material the plates are?
You would need a jig to grind the double sided blades.
You will also need to get them spotlessly clean to hold down on the magnetic chuck. Maybe a small surface plate and wet and dry to take any high spots off if they don't sit flat.
You would need to grind very carefully as the kidney style of plate could be liable to movement if i was to get to hot unless you get a machine with flood coolant.
What do you already have in the way of measuring tools to work how much to take off to keep all the clearances on tolerance.

Edit just had a quick look on eBay, you might get something for around £1200ish, remember on most small surface grinders the standard magnetic chuck size is only 6" wide at 160mm you are over this dimension.

 

[knighty]

hi

I've never used a surface grinder before, or seen one being used... I'm a quick learner and can turn my hand to most things so I think I should be ok... have a few duff plates/blades I could practice on

£1200 is ok by me, more about getting my monies worth than the actual cost

I've got some decent micrometers etc.. old school stuff that was my fathers

tolerances are pretty wide, they're call clamped together by the ring that screws on the front of the mincers, but most have a spacer in their so the plates/blades just need to be thick enough to take the strain of use, the'd still clamp in fine if they were half as thick. figguring I only need to take a tiny skim off to put a new edge on, not actually take much material off

 

[Kent]

If you have three phase I say go for it the flat ones are easy done! The other less so as mentioned your going to need a fixture

Where are you though someone might be able to help out with doing them or know a man who can

 

[WorkshopChris]

tolerances are pretty wide, they're call clamped together by the ring that screws on the front of the mincers, but most have a spacer in their so the plates/blades just need to be thick enough to take the strain of use, the'd still clamp in fine if they were half as thick.

Not 100% from the photos but the double bade is the bit to watch, your will to take the same amount off the centre boss as comes off the angled blades to get your cutting effect. take to much off the centre and it will lock up.
I presume the face to face measurement of 2 bosses needs to be just a little over the plate thickness, if that makes any sense.

 

[knighty]

center bosses are just short of touching each other between the plates

clamping pressure on the blades is set by hand - tighten the front ring on the minder up, back it off a little then tighten it slightly... bit like doing a tapered wheel bearing




I'm in Sunderland if anyone is local ?

I found a place not far away, but wasn't every impressed when I went to see them, factory was nice, guys were cowboys, quite happy to pay someone half decent

 

[WorkshopChris]

Ok makes sense only used a small attachment on a kenwood chef before.

 

[Spark plug]

Have you tried these:

http://www.wilkinsonsaw.co.uk

The are realy good at what they do and very helpful.

 

[Maker]

I can't help but I have to ask, what does it mince? It's scary looking.

 

[Wedg1e]

We've had parts made by QRS in Hartlepool, they're often surface ground to a nice finish; tell Dale or Matt that Ian from NDT sent you

 

[ronan]

There is nothing really to surface grinding, but you cannot remove vast amounts of material with one. They can be dangerous if you do decide to take a big grind, the wheel can explode. There was a company in dublin called comet engineering doing all those blades, i approached them for a job, but the pay was a bad joke.

 

[MrFluffy]

Most of the cheap ones on ebay are probably suffering with bad spindle bearings which cause marks on the ground surface or burning or worse.
A stone will cost 25 quid upwards and will need to be the right grade and fit the machine diameter. And you'll need a diamond dresser to keep it in good shape and concentric when mounted.
I've fired workpieces out of mine on a few occasions and its heavily guarded and on one occasion the 50x50x200 block of steel ended up embedded into a stone wall 6ft away. Stone explosions due to improper technique or material are also usually featured heavily in workshop safety videos and I don't ever want to be around one when they do that.
I wouldn't be without mine because I use it a lot with jigs and a spindexer and a sinus dresser etc, but I'd approach it as one of the most dangerous things in your shop from a learning to how to use it and maintain it correctly...

 

[WorkshopChris]

but I'd approach it as one of the most dangerous things in your shop from a learning to how to use it and maintain it correctly...

couldn't agree more.
Many people see one in use and think that looks easy.
It can all go wrong in a split second.

 

[knighty]

I can't help but I have to ask, what does it mince? It's scary looking.

dog food - there's 30hp motor powering that sized mincer, got to b a lot of torque by they time it's geared down to a few hundred revs!

guy working for me once dropped a 10mm threaded high tenstile bolt into the mincer with some meat... it ruined the blades/plates but they took a few chunks out of it on the way before it locked up and the motor belts started to slip!

 

[knighty]

Edit just had a quick look on eBay, you might get something for around £1200ish, remember on most small surface grinders the standard magnetic chuck size is only 6" wide at 160mm you are over this dimension.

could you link me to the sort I should be looking for ? - just to give me a decent idea ?


thanks

Alan

 

[slim_boy_fat]

I can't help but I have to ask, what does it mince? It's scary looking.

Just about anything you like. "Resistance is futile......"

 

[WorkshopChris]

could you link me to the sort I should be looking for ? - just to give me a decent idea ?

Ok this is the sort of thing:-
http://www.ebay.co.uk/itm/Jones-Shi...390621?hash=item3d1cee655d:g:OPYAAOSwPc9Wzf13
http://www.ebay.co.uk/itm/Hydraulic...636854?hash=item1a1497b736:g:uY0AAOSwI3RW-RaF

BUT you really need someone local who can confirm the 160mm plates will safely hold down on a 6" magnetic chuck with a little overhang each side. i would imagine it will probably be ok.

If you need to go up size in magnetic chuck the price is going to go up.
http://www.ebay.co.uk/itm/Jones-and...713277?hash=item21077f70fd:g:Z3gAAOSw3KFWetMA

You are going to need to budget for grinding wheels and mounts to suit the machine, a diamond dresser, maybe coolant tank and pump.
Plus would you need to have someone make some jigs to grind the double sided blades.

Now for one more But, I don't want to sound negative or tell you how to suck eggs, but if you haven't done this sort of thing you really do need to find someone to give you some hands on assistance to get you started and up and running.

This bit is just my personal feelings but i would not be spending this sort of money on a machine without seeing it running under power and being able to inspect it, but once i had seen it and decided i would not let it out of my sight. They are the most unforgiving machines to move. One push, lift or sling in the wrong place and its possibly scrap when you look at the repair costs. While moving the table must not be touched, its important to get the slinging spot on. then the strapping down is also just as important.

Hope this helps.

 

[knighty]

that helps a lot

I'll see if I can fine a decent grinding place further away and see if they'll let me watch them do a few blades/plates for me... offere a few beer vouchers to sweeten the deal

thanks :-)

 

[Maker]

dog food - there's 30hp motor powering that sized mincer, got to b a lot of torque by they time it's geared down to a few hundred revs!

guy working for me once dropped a 10mm threaded high tenstile bolt into the mincer with some meat... it ruined the blades/plates but they took a few chunks out of it on the way before it locked up and the motor belts started to slip!

Better not get on your bad side, that would work wonders on a body.

 

[WorkshopChris]

Better not get on your bad side, that would work wonders on a body.

Be more worried about a man with a big freezer and band saw.
Once saw a program on tv, forensic type thing they were cutting frozen parts up with a bandsaw, no mess or blood as it was frozen, just a bit of dust to clean up before it melts and turns back to blood.