Bench Grinder

[Clive FosterParticipant @clivefoster55965]

Another happy Creusen owner. Mine is a Morrisflex / AJH version on a vacuum dust collector box which is brilliant for keeping the workshop cleaner. £300 – 400 (ish) of E-Bay. A bit more affordable than new, albeit with significant signs of abuse with one grinding rest gone AWOL, a seriously abused wheel one side and tatty wire brush on t'other.

Made me a new grinding rest from welded up steel plate. Turned out to be more of a job than I anticipated to make a really good job, especially factoring in design time, even though I had a good one to copy. Reminded me why I never made better ones for the Whitcote bench grinder I'd had for over 35 years. The pressed tin ones were just about acceptable so any replacement had to be right, really right. Quick'n dirty weld'n bodge wouldn't have done. Helped that I put a cup wheel on one side and used a tilting table type rest for most of my tool grinding which greatly reduced the amount of time spent on the factory Whitcote ones.

That rest is yet another still born article for MEW. Nice drawings done and pictures of making so it only needs text. Sized for the Creusen but altering for any other grinder is just a matter of scribbling on new dimensions. Maybe one day.

Clive

[John Hall 7Participant @johnhall7]

..Wattage is quite important depending on what you intend using it for…the small wattage fancy ones with lights etc are ok for light duty jobs but will soon stall with very little pressure…

i have. 450watt SeLey BG150w/90….About £80……I’ve fitted an adapter on the right hand side that has a half inch chuck screwed on the end..This accepts small wire brushes os different size and shapes…which I ipyse for rust removal and thread cleaning…it’s also good for holding small round objects that need to be cleaned or polished..

it does most things I need but even at 450 is not that difficult to stall….that’s why I think buying the smaller models is wasting money…

[John Hall 7Participant @johnhall7]

[Ron LadenParticipant @ronladen17547]

The grinder arrived and first impressions are good, it certainly looks to be decent build quality. I only have the old ebay cheapie to compare it with and that would make anything look good.

It has the usual sheet metal tool rests they are a decent gauge and have 2 bolt fixings but a bit limited in their range of adjustment. In the future I will probably make some better fully adjustable ones more suited to tool shaping/sharpening which is what this grinder will be mainly used for.

Where the eye shields fix to the mounting arms looks weak, as Mark suggested I can see those easily broken. I am impressed with the right hand magnifier though its quite powerful and could be quite useful. The built in lights..? well they do add a bit more to the work area.

I ran the grinder for 20 minutes and it was barely luke warm so pleased with that, I couldnt touch the old one after 10 minutes. I am awaiting for a diamond dresser but the supplied wheels are very good, quite true. I have replaced one of the wheels though with a green wheel for carbide.

The rating is 250 watts and I suspect that is a good 250 watts as I went in quite hard shaping a piece of 8mm tool steel and it made no attempt to slow and stall.

So overall I am pleased with it and I think good value for money and I guess thats what counts.

[David George 1Participant @davidgeorge1]

Those tool rests look very flimsy to me I bought a Crusen and they are more stable but I still had to reinforce them.

David

[Ron LadenParticipant @ronladen17547]

The tool rests seem to be typical of most grinders in this price range and as I said I will improve on them in the future. However they are not "very" flimsy they are quite adequate for the type of tooling work it will be used for, I wont be putting large lumps of steel to the grinder its use will be quite light duty.

[SillyOldDufferModerator @sillyoldduffer]

Posted by John Hall 7 on 27/02/2019 10:26:00:

..Wattage is quite important depending on what you intend using it for…the small wattage fancy ones with lights etc are ok for light duty jobs but will soon stall with very little pressure…

i have. 450watt SeLey BG150w/90….About £80…..

…

it does most things I need but even at 450 is not that difficult to stall….that’s why I think buying the smaller models is wasting money…

Rating electric motors is much more difficult than it might seem, with plenty of opportunity for salesmen to mislead and users to misunderstand! The label is little more than a hint, really you need the specification and graphs. Some examples:

• Is the rating for INPUT or OUTPUT? Output is more honest, but input more useful in terms of plugging it in.
• How heavily loaded was the motor when its power was measured? Electric motors can be grossly overloaded for short periods. In the US consumer goods are often specified at peak rating, i.e. flat out just short of magic smoke, I suggest this system is misleading.
• The power output of an electric motor is mainly limited by its ability to keep cool. Modern windings can run at about 140C, but doing so damages them over time. Lot's of opportunity to inflate the power rating of a motor by measuring it running unshrouded in a cool room, rather than inside an unventilated shield on a hot day.
• More honestly, motors are rated according to their expected service. There are 8 classes of operation, for example S1 is continuous while S2 is short-duty, ie it works in bursts and is allowed to cool down. My grinder is 340W S3 50% 40 minutes, meaning 'I can do up to 340W provided you don't exceed my limitations' It's fine for sharpening, but needs plenty of cooling off time whenever any serious grinding is done.

Another hint about a motor's service rating is its power to weight ratio; heavier is better. I see the Seeley claims 450W on a weight of 11.5kg, whereas Ron's Axminster claims 250W on 17.5kg. (Don't take this too seriously when the motor is an old one – they're always heavier than new motors because the heat resistance of the insulation available was inferior to modern materials.)

Naughty persons make the motor look up to 20% better by specifying INPUT watts and by measuring it while the motor is abnormally overloaded. However, if it's only wanted for infrequent light sharpening, a cheap grinder is probably 'good enough' for hobby use. BUT! If you're into heavy frequent grinding, then either allow plenty of time for the motor to cool off, or spend serious cash on a fully rated tool.

Dave

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