Truing/grading and old sandstone wheel
I was out driving this weekend and came across a guy putting a “free” sign on something at the side of the rode. Isn’t that how the trouble always starts 🙂 ?
I took a glance as I drove by and found the item to be a 17″ diameter, 2.5″ wide sandstone wheel mounted on a steel frame with a 1/2 belt driven gear…. If nothing else it’s a cool old piece (not that I have any shop space left for cool old pieces)… I just so happen to have an old 1700 RPM motor lying around… Anyway the wheel has a fairly significant hollow and I’d like to try to flatten it and restore it to service. Can I use a diamond point grader with this kind of stone or is there something else?
Any suggestions, recommendations or pure speculation would be appreciated.
Thanks in advance,
Michael
Replies
That would be cool to have! I've always wanted one.
Don't know for sure what speed it should turn at but probably not more than about 60 rpm. That would be about 50 surface inches per second.
Sears hardware used to have the metal wheels for truing up stones. Basically 4 or 5 hardened wheels on a handle that are pushed into the stone by hand. These are pretty aggressive and should get it down pretty fast. A carburundum stone could be used next to get a better surface. Make sure the center bearing is running true first.
Diamond dressers will only take off maybe 0.0005" with each pass and cannot or should not be used by hand. Best to use them on an auto feed machinist lathe.
These old stones were usually used with water.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)
PlaneWood
Thanks Mike. There is a pulley for a 1/2" belt that drives a stepped down gear on the arbor, but I haven't looked to see what the gearing ratio is as of yet. Thanks for the tip that the wheel speed should be about 60 RPM, that's good info. The arbor turns nice and smoothly but I haven't checked it for runout yet -- there appears to be a significant amount in looking at the wheel as it rotates, but it might be the wheel and not the arbor.
I found it late yesterday afternoon, hauled it into the shop and haven't had a chance to really get a good look at it as of yet. I was thinking that I could build a water trough that I could mount in the steel frame under the wheel.... I'll post a picture of it tonight. Honestly I don't know anything about a wheel of this type so any info is great. Cheers,--M
Any handheld grinding wheel dresser will flatten the surface of the wheel but it won't correct for an out of round condition. For out of round you need somthing like a diamond dresser in a jig that feeds it across the face of the wheel so that it only takes down the high spots.
John W.
Sure brings back memories of cranking the grindstone while Dad sharpened his axe. I've never seen one of those stones being used that wasn't out of round. It was prolly turning about 30 rpm and the axe gently rose and fell as Dad applied the edge to the stone. These grindstones were common on the farms and smithys in NW Pa in the 30s and it was not unusual to see a watering trough made of a section of rubber tire nailed up underneath.
BJGardening, cooking and woodworking in South'n Murlyn'
My father-in-law told me the saem story -- he grew up on a farm in Connecticut. Looks like I'm going to have to come up with a pedal operated drive. I looked at the pully on the motor that I have as well as the gearing ratio on the arbor of the stone and that 1700 RPM motor will only be geared down to 140 RPM at the wheel....
You can slow the wheel down with a wooden jack pulley. You do not have to mount the jack pulley on an axle, just put it inbetween the motor pulley and the wheel pulley. It will ride inside the belt and find its own center. The belt has to be long enough to accomadate the middle pulley.This is often done on lathes to slow the speed for large out of round turnings.
I am not sure about truing the wheel. I do know the stone is soft. Possibly a wheel dresser will do the job.
mike
Thanks Mike. Are you talking about a countershaft scheme like this?
http://www.lathes.co.uk/latheparts/page3.htmlCheers,Michael
That's a good description of what I was trying to say. Actually you may be able to mount a large wood pulley to a smaller pulley on the grinding wheel. The wood pulley can be as simple as three pieces of plywood.The center piece 1" less in diameter than the outer two. This will give you a 1/2" deep groove by 1/2" wide if the center piece is 1/2" thick. You will find that a Vee belt will work at the slow speed even without tapering the sides. Because the pulley turns at slow speeds ,slight wobbles in the pulley won't hurt the opeation of the wheel.If you want to get fancy, you could make the wheel out of solid wood, mount it and cut the Vee groove with a router and Vee groove or champher bit. I did this once.
I temporarily mounted the router on a support, the champer bit centered on the solid pulley. Advance the bit about 1/8" and turn the wheel by hand.Do this until you have cut at least 1/4" deeper than you need for the belt. Remove router, install the belt. Turn the motor on.You have a 1/4" to play with to true the wheel. I use lathe tools but coarse sandpaper on a fixed block will work too. Pencil a line around the perimeter. When you have removed the pencil line the wheel is round. Facing off the sides would be nice but not necessary. I do it with a gouge while the lathe is running.The plywood wheel is easier and faster, plywood is tough to true up though.
mike
Michael
I have one of these old beauties & found the same issues when I got mine. The lack of centre in the arbour may be what is causing the wheel to run out of round & would be the first place to start. Mine was really sloppy & so I turned a new arbour to neatly fit the wheel & shaft. My frame required a bit of work to stiffen it & when I was happy with that & the wheel ran OK I tried using conventional wheel dressers but after a couple of hours of frustration set up a jig for a 4" angle grinder & dressed it with that. Pretty dusty but effective.
An old timer told me that you run your wheel in water but the wheel should not sit a puddle between use. The reservoir should either be able to be drained or to drop away from the wheel. All that staying wet does is soften the wheel unnecessarily & it will run out of balance.
Have fun with it.
Don
I am not sure, but would think that if the stone turns slowly enough that being out of round wouldn't matter.
Frank
It's probably just more of an anoyance if the wheel is a little out of round but mine was too far out to effectively use. Now that it is pretty true a rest can be utilised as well.
Don
Don,Great idea using the angle grinder... I was thinking that I was going to have to use something a lot more aggressive than a diamond dresser to true this stone... Thanks for all the tips.Cheers,--Michael
Castle, be sure to have each wheel turning in opposite directions and stop when no chalk shows. Another way to slow the wheel is to introduce a speed reducer to the drive belt. They come in a variety of ratios. Steinmetz.
Castle, That is a whetstone Don't confuse the word with WET
Soaking that stone with water may not over balance the stone, but when it is partialy dry, the retained water will really over balance the wheel.
My solution to dress such a wheel, is to apply colored chalk to the periffery of the wheel, then using a 4" wheel mounted in a corded reversable drill,
Start the big wheel moving first, then, use the small rotating stone in REVERSE to slowly traverse the wheel's face left to right and right to left while steadying and traversingthe machine on a horizontal ledge.
Stop both wheels occasionally to check your progress
When all the chalk is gone the wheel is just about perfectly round. Steinmetz.
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