How to make this part.

[knight_toolworks]

One thing I plan on making with the shopbot is totes and knobs on the shopbot. The tote is the rear handle on the plane. This is not hard to make. It is made from tropical hardwoods 13/16” thick. I usually draw the shape onto the board bandsaw it out sand it with a drum sander to final shape then route the edges with a ½” round over bit. It takes two passes for the right curve.
Ok first how to get the shape in a form to use on the shopbot. Thinking of using the probe for the job. Since there are a lot of different shapes to deal with.
Now cutting it out. I can see a ¼” bit cutting them out maybe leaving a tab on each corner. I plan on cutting them out of whole boards. Grain direction is critical so there is waste in cutting them out.
So do I need to cut the part fully out and then mount it in some holder to round over the edges? Then flip it and do the same thing? Do you have to use a roundover bit?



8788

[gerald_d]

Rounding over of hardwood (often not perfectly flat) is not the SB's strong point - a table router will be the better tool.

[harryball]

I think I'd use a midi lathe to make the knobs. Or a large lathe and make a whole row of knobs them cut them free.

The tote profile is easy and simple enough, on the bot you can make even more creative totes then finish them up with a table router, sander etc... I've seen nice totes with scrolls in them and side textures etc... I think THAT is what the bot would do well for you.

Robert

[knight_toolworks]

rounding over is a bear on the router table. the tropical woods tend to grab when you start on the endgrain. you can do one side starting on regular grain but when you flip it you start on endgrain and it tends to grab. I think the fellow who makes them do a climb cut instead.
but I see what you mean the piece would ahve to be in the exact place every time. the hight would have to be perfect. been thinking of some type of jig that they would drop into to hold it pefrectly.
right now I have the midi to do the knobs but it would be nice to get the shopbot to do it. too.
then I could have it two several different types as needed.
I like the idea of the scrolls thats a good idea. cutting them out on the bot would save a lot of time over the bandsaw and I would not have to use the drumsander for the final shaping. that takes a fair amount of time.

[ryan_slaback]

Could you take out a roughing pass with the 1/4" cutter so that when you use the 1/2" roundover in a table router it has less meat to take off?

[mikejohn]

Steve
How is the tote held to the metal base?
Could you use the same method to fix it to a jig which you could then flip over?
Shopbots are good for making precise jigs


.............Mike

[knight_toolworks]

there is a diaginal hole through the handle. but it would not work well for a hold down I don't think. I was thinking of a vacuum pump to hold them in place. I have a big one on hand.

[mikejohn]

Steve
If you mean that you have a hole going right through the handle, this would be ideal for a hold down jig.
I can think of a couple of designs, including one to adjust for different thicknesses.

........Mike

[mzettl]

Steve,

Having been a plane collector for over thirty years, I am quite familiar with the materials and design of these totes and knobs. I've even made and repaired a number of them over the years. I can understand your desire to try to automate and speed up the process. The tote is a deceptively simple appearing part. It is not easy to make.

That being said, I think that the initial profile is easy, and the Bot could crank those out quickly. In fact, the roundover on the first side would be relatively straight forward, as you would have a totally flat side against the table, and it could be held with a combination of vacuum and a closely fitting pocket.

The problem comes with flipping it over to round over the other side. The flat surface is now quite small, and any pocket that is deep enough to hold the piece would get in the way of rounding over the "up side."

I think Mike is right regarding the hole in the handle being employed as part of a hold down. Since the base and the top are not rounded over, a jig employing a block at each end, and incorporating a through bolt, tightened to secure the piece, would probably work.

I would design toolpaths for the round over that would make two or three passes, the last removing only 1/32 in. or so to try to leave as smooth a finish as possible. You would need to use a roundover bit that has no bearing. Whiteside makes these.

Once you get to that point, you're still going to have some hand shaping, as the top of the tote has a taper from front to back, at least in many of the more graceful examples I've seen. The base is also rounded over at the front, and has a very subtle taper, especially in thesmaller sizes. I don't think you could easily do this on the Bot.

Finally, there are a couple of different tote designs based upon the size of the plane. In your picture, you're showing what appears to be a #2 or #3. Starting with the #5, the tote is slightly larger, and there is an additional screw hole in the front of the base.

All of this begs the question, how many of these are you planning on making? If it's a lot, then it may be worth all the time in programming the toolpaths, making the jigs, etc. If it's just a few, then using the Bot to cut out the profile, then doing the rest "by hand" may actually be more time efficient.

Sorry for the length of the post, but I hope I've added something useful for you.

Matt

[knight_toolworks]

maybe your right with the hold down.
not sure on the quanity. cutting them out would be the biggest time saver.
rounding them over would save some effort. but if I only did the endgrain side the one that I have to start the cut on the endgrain that would be the most important.
but there will be quite a few different designs as I plan on making replacments. so cutting them out will be first and rounding them over may or may not happen.
what about using the shopbot as a overhead pin router for the roundover?

[mzettl]

My only concern with using the ShopBot as an overhead pin router would be the access and visibility. The Y carriage is in the way, and it seems to me it would be awkward (read dangerous!)

I think a good holding fixture with two firmly mounted handles and a couple of De-Sta-Co clamps would work with a table mounted router or shaper for the roundover. It would still require careful feeding and concentration to avoid catches.

[mziegler]

How about a duplicator? That should be doable for small orders. Some where on the internet there is free plans for a home made duplicator that can easily be builded in one day. Mark