Router Forums banner
1 - 10 of 10 Posts

·
Registered
Joined
·
251 Posts
Discussion Starter · #1 · (Edited)
As part of a continuing quest to make a decently working gear toy for my granddaughter, I came to the point of needing to use a 1/8" router bit with a set of CNC cut gear patterns.
I'd have used a bearing guided flush trim bit but I haven't found any available.

So, I started looking for pin guided routing setups. I found the table type with the router overhead, which is a dead end for me. I found found few setups for an overhead guide pin on a typical router table. I did find two commercial products, the MLCS Daisy Pin Guide and the Veritas® Pin Router Arm - Lee Valley Tools. Even before completing my homemade pin guide, I could see the value in having more working capacity, both in XY and vertical (Z) directions. I decided on the Veritas pin guide arm (VPGA), without actually realizing its size and mass. In hindsight, I think the Daisy pin guide would have been a good alternative.

But, I have the Veritas, so I set about mounting and setting it up. I tried fitting it on the corner of my Bosch table, similar to the instructions, which really only apply to Veritas tables. The VPGA would not fit my table, so I needed to make an extension, which I needed anyway for the Incra LS position, that should arrived today. Nominally, I would use MDF, even two layers of 3/4" with the top sheeted with melamine, but the extension needs to be large (27"x27") and the sheer weight of that would tip over my table.

So, my plan is to build what is essentially a torsion box extension table using a new-to-me product, resin impregnated honecomb (source of the honeycomb material). That also is on order, due to arrive today. I also plan on making a couple of lightweight table tops for two folding tables, replacing the heavy particle board tops. Making the router table extension with the honeycomb will be a good learning exercise for the larger table top projects.

But, in the meantime, I opted to make a temporary extension from 1/2" MDF and brace it with 1x2s. I tried it first without the bracing, but the weight and leverage of the VPGA was too much for the unsupported, thin MDF (no surprise). With the bracing, the VPGA is quite solid and stable. Where the unsupported table flexed and resulted in the VPGA pin/holder not being perfectly vertical, the supported table allows for it to be quite acceptably perpendicular to the router table.

Lack of perpendicularity with the unsupported extension (very narrow band of light towards the lower end). This is probably good enough for woodworking, but the table flexed enough I felt it was not rigid enough for actual use.


The VPGA comes with three guide pins, 3/8", 1/2" and 3/4", with 1/4" being available as an option. I need both 1/4" and 1/8" guide pins. So I machined some out of brass.


My first go at using the VPGA and a 1/8" bit was working well until I snapped the bit. As thin tools can go, I probably took too big a bite or used too much pressure. This caused me to assess the situation. With at least the gear that I was cutting with when the bit broke, there was a lot more stock to be removed than I realized. I decided to rout out the bulk of the extra material in the base of my hand cut gears using the 1/4" bit to be followed up with the 1/8" bit.

I cut one gear of each size with the 1/4" bit and tried them on the peg board. They worked great and now I think there is no need to even use the 1/8" bit. I will proceed to complete the other gears with just the 1/4" bit. That bit has 1" long flutes, so I am thinking of stacking two of the gears, in part to spread the wear out on the flutes, but also so I am not having to cut each gear individually. I am, however, sensitized to not use too much pressure, which raises questions about how much material can be cut and in a trimming operation, rate of feed to avoid burning. For another post, eh.

Rick
 

Attachments

·
Registered
Joined
·
251 Posts
Discussion Starter · #3 ·
Nice looking setup, Rick. It's fairly easy to snap a 1/8" bit so hogging out the bulk with a 1/4" bit makes sense. Still looking forward to seeing the finished project!

David
I've decided there is no need to mess with the 1/8" bit. The gears work just fine after having used just the 1/4" bit.

I messed up the small gear template you made for me today. I had missed one small gear yesterday when running them all in stacks of two, with the 1" bit raised in the table. Today, when I set up to run just the one (at half the height), I had everything set up, stopped for a moment to look things over and decided it was all good. First tooth I touched, cut into the pattern above the gear. I'm bummed. Didn't even really need that last gear. It was my first trial gear when just figuring out the bandsawing/sanding regime.

Now I would like to repair the damage. I am thinking of using Bondo Wood Filler to fill the divots and then clamping one of your CNC's gears to it for reprofiling that tooth. Won't be as pretty, but it will be usable as a pattern should I decide to make more gears from Baltic birch plywood.

The wood filler is used by a pattern making friend for quite a variety of filling and repairs. I may just take the gears with me and visit him this weekend as part of my Portland, OR trip. He would enjoy helping me with the repair.

Rick
 

Attachments

  • Like
Reactions: difalkner

·
Registered
Joined
·
24 Posts
I am enjoying your gear quest! I hope to one day make some wooden clocks. In the past I though scroll saw with bits and sanding blades but this looks like the trick! I can not remember from the other thread did you make or procure your patterns from someone?
 

·
Registered
Joined
·
251 Posts
Discussion Starter · #5 ·
I am enjoying your gear quest! I hope to one day make some wooden clocks. In the past I though scroll saw with bits and sanding blades but this looks like the trick! I can not remember from the other thread did you make or procure your patterns from someone?
Thanks, Sam. Initially, I bandsawed and sanded the gears from MDF using paste on paper patterns. That didn't works as well as I wanted, so I went looking for something better and hit upon CNC routing. I don't do that, but David Falkner, a moderator of these forums, 'difalkner' helped me with generating 3D CAD drawings that he then used with his CNC router to cut one gear of each size. See post #18 of the "Routing Gears for Gear Toy" thread.

I could have had David cut out the other 15 gears I wanted, but I wanted to "make them myself", since it is something I'm making for my granddaughter. I opted first to try to "fix" my hand cut/sanded gears, which is the stage I'm at. That is working well enough, I'm not likely to make any new gears directly from the pattern gears at this time. I do want to save them for another time or another project.

Plenty enough guys make some fine work using scroll saws and sanding blades. I was going to do that, but I'm glad I'd previously figured out how to set up my bandsaw with narrow blades for scroll-like work. I'm super glad I didn't try doing these with a scroll saw.

Rick
 
  • Like
Reactions: Samandothers

·
Administrator
David
Joined
·
3,978 Posts
Now I would like to repair the damage. I am thinking of using Bondo Wood Filler to fill the divots and then clamping one of your CNC's gears to it for reprofiling that tooth.
Rick
As I read this I was thinking 'that's what they make Bondo for' and then saw you're on the same page - LOL! You could also use epoxy and fiberglass cloth without much difficulty.

David
 

·
Premium Member
Joined
·
20,450 Posts
Some time ago I looked that gadget up, a pin router, Move the pattern over the while the router cuts the stock attacned underneath the pattern. I think it was by Veratas, and wasn't available. Really neat to see what it can produce.
 

·
Retired Moderator
Joined
·
16,385 Posts
They still sell it Tom. Veritas® Pin Router Arm - Lee Valley Tools

Having the router overhead and putting the pin in a table would work too. BJ made a frame to hold a router that attached to the back of the motor on his radial arm saw.
 

·
Registered
Joined
·
251 Posts
Discussion Starter · #10 ·
Some time ago I looked that gadget up, a pin router, Move the pattern over the while the router cuts the stock attacned underneath the pattern. I think it was by Veratas, and wasn't available. Really neat to see what it can produce.
While I was looking for information on the Veritas Pin Arm, I came across someone's post saying it wasn't available, perhaps that was your post. But, they are available now.

I think I've hardly scratched the surface of what it can do. Oddly, I have not, had in my head, had any notion or thought of making the kinds of things it is capable of. What I have learned from this endeavor is that "guided" routing is possible with smaller diameter router bits than are available with ball bearing guides.

They still sell it Tom. Veritas® Pin Router Arm - Lee Valley Tools

Having the router overhead and putting the pin in a table would work too. BJ made a frame to hold a router that attached to the back of the motor on his radial arm saw.
In my search, I came across much more information/examples of the overhead router with the in in the table, than I did with an overhead pin. Getting a table/machine dedicated to pin routing just would not work for me, with the limited space I have. Having a router table at all crowds the space I have. Adding the extension complicates and exacerbates that problem because it becomes less portable and less stowable. I am glad there is a solution that can work on my existing table (with extension). And adding the extension solely due to the guide pin is sort of moot or irrelevant because I will be needing the extension in order to mount the Incra LS Positioner, once it gets here, which was in the plan long before the need for pin guided routing capability came along.

And then there is the matter of whether you want to see where the pin is guiding things and you can't see the cutting in progress (in-table router) or whether you want to see the cutting and not see where the pin is guiding (overhead router). With only this one experience, I can only say that I am pleased with the overhead pin/in-table router.

Rick
 
1 - 10 of 10 Posts
Top