I have designed and am now starting to build a sharpening unit to grind, sharpen, strop and polish chisels, plane blades and carving tools. It will have a 12 inch ball bearing mandrel with 1/2″ threaded ends, with one side right hand thread and the opposite end is left handed, with a 3 step pulley mounted closer to one end of the 12″ shaft. The step pulley will have a 2″, 3″ and 4″ pulley. The unit has a base plate that will be clamped to the bench, an intermediate plate with the capability to loosen the drive belt enough to allow it to move from the smallest pulley to the largest and also to tighten the belt , then a top plate which mounts the motor and has the capability to move the position of the 2″ motor drive pulley to align with any of the three pulley positions on the step pulley.
The electric motor is an old Sears 1725 RPM and was built in 1954. Using the three step pulley on the driven shaft allows the following speeds. The 2″ driven pulley will be 1725 RPM, the 3″ pulley is 1149 RPM and the 4″ will be 863 RPM.The motor can be wired to run in either direction.
I plan to have a 6″ fine grit white grinding wheel on one threaded end, then a pillow block, next the 3 step pulley, the remaining shaft will have circular leather strops (about 2″ to 3″width in total) with different configurations for stropping carving tools, then the other pillow block, and cloth polishing wheels on the other threaded shaft.
My question is as follows: I know that usually grinders have the wheels spinning from the top down when facing the front of the grinder. Can I run my motor so that the wheels will spin from the bottom up? I believe that this would be safer for stropping and polishing carving tools and shouldn’t be a problem for grinding chisels and plane blades, especially at 863 RPM.
Replies
cutoff,
Alternatively, you could strop with the edge of the tool pointing down...
Regards,
Ray
Thanks for your response. I'll go with the flow and have the wheels turning in the normal rotation.
jon
I beieve most carving tools are stopped/honed with the disc running away from the edge. You might consider a reversing switch. I put one on my lathe a number of years ago, but can't recall the details at this time. I think it was a Delta part.Alan
http://www.alanturnerfurnituremaker.com
CUTOFF, 1725 and lower speeds are fine for some applications, but 3450 is needed for smaller buffs and wire wheels and final buffing with a canton cotton buff.
A matched set of TWO 4 step 'Cone' pulleys would be most convenient and won't require any slack take up adjustment.
Also use segmented link belts as they are 'Stretchy', adjustable and quieter.
You can buy left and right handed tapered threaded arbors to attach to the shaft ends so you can quickly switch cotton or felt buffs /sisal brush wheels etc etc .
Also, build up the pillow blocks with riser blocks on your benchtop ,so you'll have ample room for larger or complicated items .
Have the most used wheel projecting beyond the bench and as close to the forward edge as feasible.
A dedicated free standing pedestal would be more convenient and easier to access from either end.
NEVER run any wheel running upward if you value your eyes , lungs or neckties.
Build and install shields to cover the wheels (Grinder wheels can shatter ,wire wheels can 'Shed' and buffing compound is messy.) Steinmetz
Edited 8/4/2004 9:29 am ET by steinmetz
Edited 8/4/2004 9:42 am ET by steinmetz
Edited 8/4/2004 6:45 pm ET by steinmetz
Thanks for the good suggestions. I do have a 4 step pulley that will fit the 1/2" motor shaft and also have a 3 step pulley on order to fit the 5/8" mandrel shaft. I calculated that if I use both step pulleys it would give me the option of speeds from 863 RPM up to 3450 RPM, so I'm going to do it.
I had considered using a link belt as I had previously installed one on my old Delta band saw and it got rid of the vibration and you've convinced me to put one on this project.
I definately intend to manufacture some shields.
By the way, did you ever build that chest using the hardware I sent you? I use the low angle pocket plane when needed.
regards,
jon
Jon, Great to hear from you again. I kept your e-Mail address to inform you regarding the trunk.
Sorry to say, A million things popped up to deter me from advancing beyond drawing up sketches and determining the final dimentions for the trunk
I do have plenty of rough sawn pine boards 5/16"x4" x12 ft long to create a 'Rustic' look.
The interior will retain the roughsawn look, while the outside will be sanded and scuffed in places to a 'Well used' condition.
If you,d like, I,ll send you some jokes/stories and poems I send to my friends and cohorts.
My Grandson Keith Is now attending college in California learning film direction and such.
Before graduation from his Connecticut Academy, he made two short movies (One of which was based on a story I typed up). ( Even added my name to the opening credits)
He looks the part, as he has flaming red hair and resembles Ron Howard but with hair.
Thanks for remembering Ed from Ct.
Edited 8/4/2004 10:08 pm ET by steinmetz
Put on guards. Lots of guards. Having the thing throw a sharp tool in your face isn't something you soon forget. You count your fingers and take a deep breath wonder how you managed not to be dead. I can get a mirror edge plenty fast with a hand strop. Cloth wheels round the edge. Leather wheels can catch and throw things. One time was all I needed.
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