Thread: Light Duty Metal Linisher

Gavin,
I purchased a multi-tool with grinder at the recent H&F sale - just got round to trying it out.
The vibration is very high.
The naked grinder, no wheels or attachments, runs OK (but not brilliant).
One wheel is OK, but with the multi-tool hub added, terrible.

I produced a rough balancing fixture by levelling a piece of float glass on 3 packers, then stacked up parallels to provide the rolling datums, and used some 19 mm bright bar as the shaft.
Easy to pick up the heavy spot, and experimented with washers and sticky tape to see what I could do.

Temporarily, I have 4 x 17 mm steel plated washers duct-tapped inside the hub opposite the heavy spot.
Started the grinder without a wheel at other end, and it operates sort of OK, perhaps good enough for a linisher.

I am sure some close attention would get the balance better, but no idea on the balance along the shaft which could be the residual unbalance.
I will try a point suspension mid-way along the hub shaft to see if I can pick anything (thinking of a ball bearing in a keyway sort of thing).

Any comments from forum members on balancing a multi-tool hub ?

John.

My multitool setup is very smooth but the Abbot and Asby grinder it's on is also super smooth to begin with. If the grinder is a little bit out of balance I imagine that adding a big rotating mass like the multi will be really noticeable. Have you tried the grinder with two conventional wheels?

I didn't attempt to balance mine but got it running smoothly by paying attention to runout. Turn it slowly and mark the high spot on the wheel with chalk, then mark the shaft at the same angle. Turn the wheel relative to the shaft by an arbitrary amount and try it. Repeat as necessary. The idea being to find the sweet spot where the errors cancel.

Bob,
My old A&A grinder operates much smoother than the new one.
The old is nameplated 600 W, 2.8 Amp, 1989, Hurstville.
The new is 900/600 W, 3.8 Amp, no date, made in China.
The new one operates without any grinding wheels mounted with some vibration, not in the least impressive.

Bryan,
Good suggestion, I will follow that up.
The instructions refer to applying light taps to get good running.
The hub does have some discernible run-out, but a dial gauge on the shaft shows minimal deflection.

John

ive just been considering adding a disc sander to my list of tools, for touching up miter cuts. sorry for the thread hijack but is that a reasonable use for one of these machines- i can cut close but not perfect for tigging, i figure a disc sander /linisher with a miter guage might let me touch up each piece closer to perfection before letting rip with the TIG

Bryan,
Tried rotating the hub on the shaft, but no improvement.
The hub run-out is about 0.1 mm TIR.
Decided to try a run anyway with a wheel on the other end.

The first hurdle is getting the belt on, depressing the tension spring does not drop the little locking lever into place - need three hands.
Accomplished by feeding on a bit at a time as the pulleys are rotated by hand.

Then the tracking is observed to be well off, so the belt must come off to allow spanner access to the attachment bolts that must be loosened to shift the mounting plate for the coarse adjustment.
Still cannot get the locking lever to engage, so jam a wood backer between belt and rubber pulley to force spring to retract, then can operate the locking lever.

What a diabolical way to get the tracking correct !

Finally running with tracking OK and probably OK vibration (still with 4 washers and duct tape).

I will use it and consider ways to get the run-out better and make the balance weights permanent.

John.

John, I think with that much runout it will vibrate, regardless of balance. How is the fit on the shaft? I guess as a last resort you could bore it true and bush it. Shouldn't really have to though.

My latch is sticky too. I lubed it and it helped but of course not for long. Once you have a belt on you can just push down on the lower belt run to pull the wheel in and use your free hand to engage the latch. I've had no probs with tracking at all.

Bryan,
I quickly learned about pulling the belt down (or up) to depress the spring, then use the other hand to set the latch.

The bush approach is hovering in the back of my mind - some day !
The hub runs on a plastic sleeve to size match the shaft - hard for the end result to be correct.

I need to improve my balancing machine first, I think I need to check both the balance across the diameter (radial ?) but also along the shaft (longitudinal ?). With so much metal spinning at that speed, very small errors will give problems.
I have yet to fit the disk - probably more problems.

I am reluctant to drill holes for balance because they could fill up with rubbish, but the hub has so many ribs with the same risk, holes would probably be OK.

I plan to operate only a roughing wheel on the new grinder, so a bit of vibration will be tolerable - unless someone comments that vibration can cause problems with the linishing.
The old grinder will be fitted with a fine wheel and a green wheel.

John.

Hi John,
Is this a single phase grinder? If so one thing to look out for is that they dont run very smoothly anyway. The hone I've built(with some help) for sharpening scrapers vibrates a little while its running. As soon as the power is turned off is runs smooth as. I believe its just something you have to put up with using single phase motors. Of course this isn't all of your problem.

Is taking it back not an option?

Stuart

Stuart,
It is single phase, and the vibration does reduce on switch-off, but it is still what I would call a "rough grinder".

I could take it back, but I suspect mine is just average for the bunch.
A test in the showroom would have the salesman saying "that's normal".
Better the devil I know.

John.

John, is the runout axial or only radial? You're probably aware of this but cheap grinders are often supplied with pressed flanges and wonky nuts. Wonky meaning faces not square to the threads. They can be trued by mounting on an arbour in the lathe and cutting the faces. Ideally you would turn up the arbour and single point the thread, then true your nuts in the one setting. The cheap flanges are best binned and replaced with turned ones. I didn't do this with my Multitool as I didn't have a lathe then, but I've done it with another grinder since and it made a big difference.

PS I should have said nut, singular, since they are opposite hands. You will be dealing with the RH one so it should be straightforward. If you need to true the LH one you will have to run the lathe in reverse so it doesn't unscrew.

I just checked the runout on mine and it's .1mm+ radially, but there's 3 high points per turn. Axially similar but only 1 cycle per turn.
It's not silky smooth but not noticeably bad. So it can run ok with some runout.

Gavin Newman said: Buy the Multi-tool and put it on a decent 8" grinder and it will outlast you. I've had one on a good Skil grinder for as long as I can remember (20 year plus I think) and it gets absolutely thrashed and keeps coming back for more.

Ditto, ditto, ditto & ditto!

Zero vibration to speak of-maybe that's the good old Skil 8" grinder's quality?

I always give the belt a 'kick start'- a manual shove/spin just before I turn it on a left over habit from the days of using a small genset!

Belt change takes 20 seconds max. I lean my fat belly into the rubber wheel to compress the spring, and with the right hand, push the 'keeper' down to hold it retracted.

Originally Posted by Stewey

Ditto, ditto, ditto & ditto!

Zero vibration to speak of-maybe that's the good old Skil 8" grinder's quality?

I always give the belt a 'kick start'- a manual shove/spin just before I turn it on a left over habit from the days of using a small genset!

Belt change takes 20 seconds max. I lean my fat belly into the rubber wheel to compress the spring, and with the right hand, push the 'keeper' down to hold it retracted.

Yep, the old Skil stuff was good, on thinking back I bought the grinder well before I was married so it'd be at least 35 years old now as still going well (as is the marriage).

My multi-tool latches in the compressed position when the idler wheel is pushed back so belt changes are a doddle.