Author Topic: What sanding tools for wheels and pinions?  (Read 26149 times)

Offline bobledoux

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What sanding tools for wheels and pinions?
« on: April 20, 2007, 08:32:05 PM »
I'm using a scroll saw to cut my wheels and pinions.  What can I use to sand the teeth to the line?  I have a Dremel tool and could mount it upside down in a router table.  But I find no source of abrasive sanding tools for very small diameters.

The sanding belts intended for scroll saws are too wide to make the narrow curves.  Anyone try mounting small files on a scroll saw?

bobbytbird

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Profile Sander
« Reply #1 on: April 22, 2007, 09:05:56 AM »
I have a Porter-Cable profile sander that works well. It has some very tight rubber profiles designed to take adhesive sandpaper. I have also designed several of my own profiles from erasers. See http://www.porter-cable.com/index.asp?e=547&p=2784

For very fine sanding I use a Minimot PS12 - a small German sander which is quite inexpensive. It's motion leaves a bit to be desired and even though it is very small it is sometimes difficult to control. See http://www.garrettwade.com/jump.jsp?itemID=111294&itemType=PRODUCT

Bob Thornborough

Offline bobledoux

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Gear Tooth Sander
« Reply #2 on: April 22, 2007, 03:39:12 PM »
I think the preferred sanding method would use rotary motion.  A very small wheel at 2000 rpm or less would be mounted vertically, as in a router table. The teeth could be fed into the rotating wheel.  The sanding marks would be parallel to the action of the wheels as the teeth engage and disengage.  This would result is less friction than teeth that are sanded across the tooth surface.

There are sanders intended to replace blades in scroll saws.  These appear to be the next best option.

I don't think I want to use burrs or other rotary cutting file type wheels.  These don't limit the cutting depth like a sanding material.  They are used, after all, for routing out material.

Comments, please.

bobbytbird

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Sanding Alternatives
« Reply #3 on: April 22, 2007, 06:37:13 PM »
I have purchased the sanding strips from Lee Valley that mount in a scrollsaw and found them to be less than satisfactory. Even with a significant tension there is a bowing that results in a poor sanded profile. I have also attempted sanding with a rotary tool mounted in a vise. It may work for others but I found it very difficult to control and abandoned the approach.

Offline bobledoux

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What sanding tools for wheels and pinions?
« Reply #4 on: April 22, 2007, 07:02:17 PM »
I was wondering whether the scroll saw sand strips would bow.  I saw one suggestion of building a backer board so the sanding strip could not bow.

I've had very good luck with sanding wheels in drill presses.  I've also used a  router table with good luck.  I wouldn't use a sander or milling bit is a router because the speed is far too high.  I don't think mounting a Dremel tool in a vise would be very good unless the work was sitting on a table.

On gears we want all the tooth faces to be parallel to the gear arbor.  That's hard to maintain while freehanding the work.

Amazon sells this Dremel tool table for only $17.

Milescraft-1098-Rotary-Center-Router

I think I'll give it a try.

Dave

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What sanding tools for wheels and pinions?
« Reply #5 on: April 24, 2007, 02:12:00 PM »
Why not make a plastic template of the tooth profile and a collar on the base plate of a router, you could mark off the wheel blank with a protractor and rout the teeth, see the tools section at www.davewestclocks.co.uk regards Dave

Offline bobledoux

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What sanding tools for wheels and pinions?
« Reply #6 on: April 24, 2007, 04:21:01 PM »
Dave, I've always enjoyed reading your techniques.  

I have used a router, with carbide tools, to machine aluminum with great success; running at top router speed.  I've never tried to use a router on brass.

The technique you espouse is like that presented in the 1986 wood clock articles in "Fine Woodworking" magazine.  

I wish to stay with the scroll saw cutting technique for wheel teeth.  My only issue is finding an abrasive tool to permit fine sanding to the tooth line.  I've used sanding drums in my drill press on many occasions with great success and accuracy.  The only problem is finding a small diameter drum to permit finishing the active region of gear teeth.

I have found "scroll saw files" that consist of a metal strip embedded with silicon carbide.  Hopefully, these will not cause the rounded tooth edges that occur with scroll saw sander strips.

Thanks for the suggestions.

I have found small diameter drums for use with Dremel type tools.  I may also give these a try.

Dave

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What sanding tools for wheels and pinions?
« Reply #7 on: April 25, 2007, 12:50:08 PM »
Thanks for the nice comments, heres another idea, just brain storming here so anyone jump in. I saw those fret saw strips a while ago and liked the idea but not the price. Coils of emery cloth are always up for sale and usually quite cheap, you could make clamps for top and bottom arms of the fretsaw to hold the cloth, use these with a form tool/profile behind the cloth and sand away to your hearts content. Will it work?? dont know, never tried it, whatever you choose, i would be interested how you solved your problem, regards Dave

Offline rus

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What sanding tools for wheels and pinions?
« Reply #8 on: April 29, 2007, 08:13:59 PM »
Hello all
Here is a formula that I found works for me.  I cut the teeth either by using my gear cutting engine -- check an earlier post in general discussion or by scroll saw cutting from my cad drawings, either way I sand the edges of each tooth using a scroller sander.  They come up to 320 grit. I start at about 180. I move to a lathe where I mount a birch disc turned the to approximate the profile beween two teeth and using the tool rest covered in tape, I "polish" each tooth gutter against the disc. I feed the wheel or pinion into the disc gently.  Puts a shine on the tooth edges and deburrs the the bottom.  Works for me!  Too much pressure will burn the edge. Try it out-- but don't tell anyone-- I may write a book some day-- like everyone else here.  Now you must know that the space between the teeth I'm cutting are 3/32"- but should work for larger profiles.  Let me know what you think.
Good luck and thanks
Rus
Rus

Offline Reid Heilig

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What sanding tools for wheels and pinions?
« Reply #9 on: May 02, 2007, 07:16:25 AM »
Years ago my father (a tool and die maker at the A-bomb plant in SC) had a die profiler in his personal shop which if my memory serves me used various files in a straight up and down motion. There was no rocking to the movement of the file and a true angle could be obtained. I believe the table (circular) could be tilted and that the up and down speed of the file was controllable.  He used it very often for precise shaping.I have wished many a time as I am cleaning up teeth on a wooden wheel that I had this machine. Reid

Offline bobledoux

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Die Filer
« Reply #10 on: May 02, 2007, 08:09:32 AM »
Here's one on ebay with a current bid of $78.

Item: 220107775677

Oliver Adrian 10in Metal Die Filer wRobbins Myers Motor

Its like a jig saw mounted upside down on a router table with a file instead of a blade.

Steveal

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Re: What sanding tools for wheels and pinions?
« Reply #11 on: November 06, 2007, 12:56:15 PM »

Hobbyhorse

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Re: What sanding tools for wheels and pinions?
« Reply #12 on: November 12, 2007, 03:24:38 PM »
I use a 1" x 42" sander for this. The sander has a three wheel configuration with a 1'' wide belt running vertically. I changed the drive pulleys to slow the belt speed down and run a 240grit belt on it. It works well for me.

Rhys

Gryphon

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Re: What sanding tools for wheels and pinions?
« Reply #13 on: January 29, 2009, 06:56:04 AM »
I'm new to woodwoking and scrollsaws, but would it work to use an emory board?  A fine grain one for nail filing would be more rigid than sand paper and I would think it could be mounted in much the same manner as a file.

Gryphon

Offline chuckknight

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Re: What sanding tools for wheels and pinions?
« Reply #14 on: January 31, 2009, 09:39:00 PM »
Though I've not yet tried it, I bought (at a dollar store) a sapphire nail file.  Basically it's the beefed up version of an emery board.  I looked for an old fashioned "grooved" metal nail file, but couldn't find one.

Anyway, I snapped off the blade at the handle, and the resulting blade should fit into my pinless scroll saw, and just oscillate up and down at whatever speed I set.

As it's quite stiff, I expect that it will not exhibit significant deflection, while in use.  We are, after all, talking about final sanding...not shaping.

     -- Chuck Knight