Small cast-iron shaper from Harbor Freight

[Joe Gwinn]

A while back there was a discussion of using shapers to shape forbon flatwork, and someone (Possum?) complained that all the small ones he had seen were too light and flexible to work. Probably the junk one sees in hardware stores and Sears.

I just got yet another catalog (#481-B) from Harbor Freight, and there is a "Bench top shaper/router" (item 32650) on sale for $89.00 US. I have not used this, but I have handled it (in a used tool place). It is quite solid, being made of cast iron, and looks practical. It is also a convenient size for flatwork.

http://ww2.harborfreight.com/cpi/cta...emnumber=32650

The website claims $112.99, but the paper catalog has the lower price for item 32650-0CMH, so it may be better to order by phone unless the web catches up.

[Joe Gwinn]

Grizzly has a similar thing for $89, but in green: http://www.grizzly.com/products/G8693. This is probably why HF dropped the price in the catalog. The material is not specified in the Grizzly item.

[NightWinder]

Maybe not totally related, But I went to H.F here in michigan, and they have a tiny Mill too with an xy table for like $280? It looks really nice for Close tolerance stuff. I think It maxes out at 3000rpm though : ( Just a quick mention...

[Joe Gwinn]

Maybe not totally related, But I went to H.F here in michigan, and they have a tiny Mill too with an xy table for like $280? It looks really nice for Close tolerance stuff. I think It maxes out at 3000rpm though : ( Just a quick mention...

Those little mills could work for pickups. The square-column mills are far easier to use than the round-column mill-drills. Actually, for cutting steel, it's the lower speeds that matter, unless one is using very small endmills and drill bits. For aluminum, one almost cannot go too fast when using the smaller tools. With plastics, faster works when milling, but not necessarily when drilling. Cooling with tap water is usually very helpful in preventing the plastic from melting.

[R.G.]

OK, took a look. Obviously, if a router works, this works.

But I've seen cabinet makers missing fingers. What would make this really great is one of:

- a laminate trimmer bit with a bearing under it running on a template and a way to connect a remote handle so your fingers are not what's moving the thing around the spinning shaper bit; I have some prototype drawings of this.
- a Robo-sander plus templates as David posted some time back. The sanding drum with bearing (how did they ever get that patented in the face of laminate trimming router prior art???) will do the job, and it's much more forgiving on fingers than a router blade.

The unit you mention has a 2" diameter opening in the table, so it may be the perfect tool for using a 2" diameter Robo-Sander tool in.

The issue with the Robo-Sander not giving consistent sizes is related to the fact that it uses cylindrical sander bands and expands a rubber cylinder under the band to hold the band in place. I probably ought to patent this (given how easily the patent office hands out patent candy) but I think it's trivial: make a sanding drum out of HARD abrasive and set it permanently in a fixed-size drum.

A diamond-grit drum comes to mind, but that's quite expensive. Maybe coarse synthetic sapphire instead. We use a small version of this for grinding down our dog's toenails - Dremel sells them - and it's lasted with no deterioration for over 10 years now. Forbon is good stuff, but it's not as tough as dogs' toenails. ]

Such a drum would not have the flexible-sides issue that the Robo-Sander does, and would be the obvious solution to the issue of shaping blanks.

Maybe the procedure is
1. make crude blanks to be shaped
2. stack, clamp and drill template mounting holes
3. screw on templates.
4. drill other holes
5. route or sand to the template

But yeah, the router/shaper at $90 is a good deal.

[Joe Gwinn]

OK, took a look. Obviously, if a router works, this works.

But I've seen cabinet makers missing fingers. What would make this really great is one of:

- a laminate trimmer bit with a bearing under it running on a template and a way to connect a remote handle so your fingers are not what's moving the thing around the spinning shaper bit; I have some prototype drawings of this.

We had been discussing this, and came to the conclusion that a shaper plus a suitable jig to hold the forbon pieces being shaped would be the best long-term solution for both safety and productivity. The shaper bit would have a ball bearing on it, to ride on the template.

- a Robo-sander plus templates as David posted some time back. The sanding drum with bearing (how did they ever get that patented in the face of laminate trimming router prior art???) will do the job, and it's much more forgiving on fingers than a router blade.

The unit you mention has a 2" diameter opening in the table, so it may be the perfect tool for using a 2" diameter Robo-Sander tool in.

Are the Robo-Sander drums et al rated for 10,000 rpm? It sounds a bit fast to me.

The issue with the Robo-Sander not giving consistent sizes is related to the fact that it uses cylindrical sander bands and expands a rubber cylinder under the band to hold the band in place. I probably ought to patent this (given how easily the patent office hands out patent candy) but I think it's trivial: make a sanding drum out of HARD abrasive and set it permanently in a fixed-size drum.

A diamond-grit drum comes to mind, but that's quite expensive. Maybe coarse synthetic sapphire instead. We use a small version of this for grinding down our dog's toenails - Dremel sells them - and it's lasted with no deterioration for over 10 years now. Forbon is good stuff, but it's not as tough as dogs' toenails. ]

Such a drum would not have the flexible-sides issue that the Robo-Sander does, and would be the obvious solution to the issue of shaping blanks.

One can also get cylindrical grindstones (called "points") made of aluminum oxide and rated for these rotational speeds.

Maybe the procedure is
1. make crude blanks to be shaped
2. stack, clamp and drill template mounting holes
3. screw on templates.
4. drill other holes
5. route or sand to the template

But yeah, the router/shaper at $90 is a good deal.

Yep. What caught my eye was the fact it was made of cast iron. I don't know what the Grizzly unit is made of, but the weight is quoted as 42 pounds. The weight of the HF unit is not given, but they must know, for shipping.

[NightWinder]

Well, I've been honing in on my shop skills. I thought it would be cool for the garage- Nice and small....

[R.G.]

Are the Robo-Sander drums et al rated for 10,000 rpm? It sounds a bit fast to me.

No, they're rated at 2000? 2500? Something like that.

But I'm an EE. Motor speed control looks easier to me than making up the mechanics. It's got to be a universal AC/DC motor; Induction motors don't go to 10K rpm, and to get it cheap, you have to put it right on the motor shaft, not gear it up. So a router speed control... (!) would work to tone it down a bit.

One can also get cylindrical grindstones (called "points") made of aluminum oxide and rated for these rotational speeds.

They'd load up with the shavings, I think. Grit's too small. You need a coarse grit that releases fibers for vulcanized fibre material. I think. I'm an EE. What do I know of materials?

The only issue I have with routers is the loss of fingers, eyes, and/or other body parts. I came up with an overhead handle. First you make a nylon or delrin template for the bottom. Not metal, in case of a disaster and the template contacting the bit. It shouldn't happen, but then that won't help if it somehow does. The template is about 3/16" to 1/4" thick, and has threaded holes in it at the centers of two of the magnet holes, probably the extreme ones. The blanks are first stacked and drilled, perhaps with a matching steel template on top, then stacked onto the soft template and suitable plastic spacers inserted and the stack screwed down. That "screwed down" includes any equalizing spacers and the matching end of the handle, and ideally is done with nylon hardware. I think 10-32 nylon is available. The handle end is adjusted to be above the top of the router bit.

The other end of the handle has a screw-adjustable height so the handle stays level, and the actual finger-holding part is above the main handle to get them out of the way in case of a disaster. Shoot, maybe you make the end of it over the stack of blanks out of 3/8" thick plexiglass so you can see what you're doing.

[R.G.]

Here's the handle I came up with.

The template gets it the right shape, the plexiglass lets you see what you're doing without re-grasping the stack, the height adjuster and spacers let you work with variable numbers of blanks, the handle is up above and away from the router blade in case something goes wrong at 10,000 rpm.

I think this gets you relatively safe use of a shaper/router.

**** NOTHING'S PERFECT!! ****
This is a legal disclaimer.

This drawing represents only what I think would be safer than using one's bare hands to guide a stack of blanks near a router head. "Safer" does not mean "safe" or that it's impossible to get hurt doing this. I do not recommend that the generic "you" do this. I only present this as a point of discussion and for the purposes of furthering thought and discourse on the topic. I make no representations about your use of this idea in any form, whither identical to the way I've presented or in some derivative form.

You agree, by your acts in using this idea, or a similar idea, that:
(a) you do so of your own free will, and were not convinced or coerced into doing so;
(b) you recognize that using a router in any manner whatsoever has certain inherent risks which can only be ameliorated, never completely removed;
(c) you take full responsibility for your own safety and the safety of others in using this idea or any derivative or modification thereof;
(d) you represent that you have legal competency and standing to allow you to make this agreement;
(e) you agree to release and hold harmless me, my successors and assigns, from any damages of any kind whatsoever, including personal injury, damage to property, or loss of income, alienation of affection or any other damages of any kind whatsoever;
(f) you agree that this agreement is binding on you, your successors and assigns in purpetuity;
(g) you agree that if any portion of this agreement is ruled unenforceable, that portion shall be severed from the agreement and that the rest of the agreement shall continue in full force and effect;
(h) to the extent that any damages are ever awarded to you as a result of your use of the information presented, you hereby transfer title of such damages to me, my successors, or assigns immediately and with no impediment to my taking possession of such damages; you agree to pay reasonable legal fees which I may incur to take possession of such damages.

[Joe Gwinn]

No, they're rated at 2000? 2500? Something like that.

But I'm an EE. Motor speed control looks easier to me than making up the mechanics. It's got to be a universal AC/DC motor; Induction motors don't go to 10K rpm, and to get it cheap, you have to put it right on the motor shaft, not gear it up. So a router speed control... (!) would work to tone it down a bit.

I'm an EE too, so there may be hope for you. But my excuse is the youth wasted fixing cars.

You are right that the motor will be a universal-wound series AC/DC motor. But running it at 1/5 speed will eliminate its torque.

They'd load up with the shavings, I think. Grit's too small. You need a coarse grit that releases fibers for vulcanized fibre material. I think. I'm an EE. What do I know of materials?

Coarse stones can be bought, and speed is your friend.

The only issue I have with routers is the loss of fingers, eyes, and/or other body parts. I came up with an overhead handle. First you make a nylon or delrin template for the bottom. Not metal, in case of a disaster and the template contacting the bit. It shouldn't happen, but then that won't help if it somehow does. The template is about 3/16" to 1/4" thick, and has threaded holes in it at the centers of two of the magnet holes, probably the extreme ones. The blanks are first stacked and drilled, perhaps with a matching steel template on top, then stacked onto the soft template and suitable plastic spacers inserted and the stack screwed down. That "screwed down" includes any equalizing spacers and the matching end of the handle, and ideally is done with nylon hardware. I think 10-32 nylon is available. The handle end is adjusted to be above the top of the router bit.

The other end of the handle has a screw-adjustable height so the handle stays level, and the actual finger-holding part is above the main handle to get them out of the way in case of a disaster. Shoot, maybe you make the end of it over the stack of blanks out of 3/8" thick plexiglass so you can see what you're doing.

This is basically what we had come up with, and ought to work. Search old postings for the story. One thing though - the plexiglass window will instantly become covered with dust. The proposed alternative was to have a hose attachment at the back (away from the operator) to which a shopvac would be attached, and it would keep the dust out of the air. Proper design of the airflow will ensure that the working area is clean enough that one can see what's going on. Basically, the viewport hole is where most of the incoming air goes through on its way to the shopvac

[R.G.]

I'm an EE too, so there may be hope for you. But my excuse is the youth wasted fixing cars.

I use song, drink and moral depravity as an excuse when pressed...

You are right that the motor will be a universal-wound series AC/DC motor. But running it at 1/5 speed will eliminate its torque.

Maybe. The thought occurs to me that one could rewire a series AC/DC to shunt AC/DC, then PWM the now lower-voltage motor for both speed and torque. It's probably worth it.

You could do even better by disconnecting the field coil, running that at a fixed current and then varying the current in the rotor for speed control. It takes making a DC supply up, but you get a DC motor then; the torque is max at stall and goes down with speed. More properly, it's torque is linear with current, so you can modulate either the field or rotor current to change speed/torque. Electrons are easy.

An alternative, cheaper and possibly better arrangement for the rotary sanding approach is to buy one of Harbor Freight's always-on-sale bench drill presses for $40. One then rearranges the base plate, table, and motor head so the motor head is beneath the table and pointing up through the table. Now you have a high-torque rotary tool with a cast-iron table to do robo-sanding on.

Coarse stones can be bought, and speed is your friend.

True. I'll go see if I can find 1/2" by 1" 10k rated coarse stones.

This is basically what we had come up with, and ought to work. Search old postings for the story.

Stands to reason. I think about it for a while and come with something other people invented long ago. Sigh. Happens all the time.

One thing though - the plexiglass window will instantly become covered with dust. The proposed alternative was to have a hose attachment at the back (away from the operator) to which a shopvac would be attached, and it would keep the dust out of the air. Proper design of the airflow will ensure that the working area is clean enough that one can see what's going on. Basically, the viewport hole is where most of the incoming air goes through on its way to the shopvac

Yeah, I should have thought of that. Two thoughts come to mind.

First is making the plexy conductive with something like a graphite rub or tin oxide. That ought to keep the worst of the dust from sticking to the plexy from electrostatics at least.

The other is to use a couple of metal supports but arrange them to be dramatically out of the way, arcing down into the fixing holes from above and with non-metal guards to avoid any possibility of the router blade getting to the metal. I saw a router hit an embedded nail once. The nail and bits of blade went flying. I'm not eager to repeat that performance, and I was just watching. We were lucky no one got hurt.

[Joe Gwinn]

Maybe. The thought occurs to me that one could rewire a series AC/DC to shunt AC/DC, then PWM the now lower-voltage motor for both speed and torque. It's probably worth it.

You could do even better by disconnecting the field coil, running that at a fixed current and then varying the current in the rotor for speed control. It takes making a DC supply up, but you get a DC motor then; the torque is max at stall and goes down with speed. More properly, it's torque is linear with current, so you can modulate either the field or rotor current to change speed/torque. Electrons are easy.

An alternative, cheaper and possibly better arrangement for the rotary sanding approach is to buy one of Harbor Freight's always-on-sale bench drill presses for $40. One then rearranges the base plate, table, and motor head so the motor head is beneath the table and pointing up through the table. Now you have a high-torque rotary tool with a cast-iron table to do robo-sanding on.

It's going to be a lot of trouble to electronically replicate a standard oscillating spindle sander, such as this http://ww2.harborfreight.com/cpi/cta...emnumber=38160. For something this simple, mechanical approaches are best. And one will blow by $170 pretty fast getting all that electronics to work properly and reliably.

Yeah, I should have thought of that. Two thoughts come to mind.

First is making the plexy conductive with something like a graphite rub or tin oxide. That ought to keep the worst of the dust from sticking to the plexy from electrostatics at least.

If it were this easy, everybody would already be doing this. Nobody has found a way to keep plastic face shields clean and polished either, so people use metal screening instead. Nor have molded plastic (styrene?) windows on routers worked. A hole plus airflow (and a well-placed light) will work far better in practice, and one needs to keep the dust down anyway.

The other [thought] is to use a couple of metal supports but arrange them to be dramatically out of the way, arcing down into the fixing holes from above and with non-metal guards to avoid any possibility of the router blade getting to the metal. I saw a router hit an embedded nail once. The nail and bits of blade went flying. I'm not eager to repeat that performance, and I was just watching. We were lucky no one got hurt.

Use only aluminum for the template, and design things with generous spaces, so things are not critical. In your proposed jig design, there were adjusting screws. This is a bad idea, as they will catch on things as well as drift. A better way is to choose shim thicknesses and cutter dimensions so it all goes together correctly without adjustment.

[R.G.]

It's going to be a lot of trouble to electronically replicate a standard oscillating spindle sander, such as this http://ww2.harborfreight.com/cpi/cta...emnumber=38160. For something this simple, mechanical approaches are best. And one will blow by $170 pretty fast getting all that electronics to work properly and reliably.

Yep, if I was trying to replicate an oscillating spindle sander, it would be really complicated. The good thing is, that's not what I'm trying to do. I need to spin one (1) rotating sander drum with no axial shaft movement at about 1500-2000 rpm under load with enough torque to sand.

The shaper table is probably better used as a router, but I think that adapting it as a sander doesn't have to be that hard. DC, even in large quantities is not that expensive. The electronics surplus market makes transformers, big bridges and caps and high current MOSFETs pretty cheap. All that electronics comes down to a line rectifier, a few big filter caps, some high voltage MOSFETs and a control IC with a few other jellybean parts.

I think the inverse of me and mechanics is true - I used to design power supplies for a living, so I think power electronics is the simplest way to do things. I recognize the myopia in myself...

One could take an even easier mechanical approach: Find a free used 1/4Hp induction motor, mount the Robo-Sander on the end of the shaft, and fixed-mount the motor under a plywood table. Right speed, lots of torque, no spindle movement (which is the point of the Robo).

If it were this easy, everybody would already be doing this.

That's right. Say, here's an interesting question. Did anyone ever build one of the earlier setups? I'd like to see one if there are any pictures.

A hole plus airflow (and a well-placed light) will work far better in practice, and one needs to keep the dust down anyway.

I believe that!

In your proposed jig design, there were adjusting screws. This is a bad idea, as they will catch on things as well as drift. A better way is to choose shim thicknesses and cutter dimensions so it all goes together correctly without adjustment.

Yeah, that adjuster for height was a last minute thought about how to ensure that a user didn't cant the holder. Making it a fixed height works. It's just more mechanically difficult...

[Joe Gwinn]

Yep, if I was trying to replicate an oscillating spindle sander, it would be really complicated. The good thing is, that's not what I'm trying to do. I need to spin one (1) rotating sander drum with no axial shaft movement at about 1500-2000 rpm under load with enough torque to sand.

The shaper table is probably better used as a router, but I think that adapting it as a sander doesn't have to be that hard. DC, even in large quantities is not that expensive. The electronics surplus market makes transformers, big bridges and caps and high current MOSFETs pretty cheap. All that electronics comes down to a line rectifier, a few big filter caps, some high voltage MOSFETs and a control IC with a few other jellybean parts.

I think the inverse of me and mechanics is true - I used to design power supplies for a living, so I think power electronics is the simplest way to do things. I recognize the myopia in myself...

Power electronics isn't expensive, although it will take some engineering to get the design rights.

One could take an even easier mechanical approach: Find a free used 1/4Hp induction motor, mount the Robo-Sander on the end of the shaft, and fixed-mount the motor under a plywood table. Right speed, lots of torque, no spindle movement (which is the point of the Robo).

The problem is that the forbon will very soon wear a groove or set of grooves into the side of a non-oscillating sanding drum. That's why people go to all that mechanical complexity to make the drum move up and down.

That's right. Say, here's an interesting question. Did anyone ever build one of the earlier setups? I'd like to see one if there are any pictures.

I don't recall any reports or pictures, so probably not. Although some people had been using routers and/or shapers.

Yeah, that adjuster for height was a last minute thought about how to ensure that a user didn't cant the holder. Making it a fixed height works. It's just more mechanically difficult...

Nah, it isn't difficult. One can buy sheet goods in various thicknesses, so one just stacks and glues.

[R.G.]

Power electronics isn't expensive, although it will take some engineering to get the design rights.

Kewl. That's what I do. That part is free.

The problem is that the forbon will very soon wear a groove or set of grooves into the side of a non-oscillating sanding drum. That's why people go to all that mechanical complexity to make the drum move up and down.

Yeah- but maybe you could just put in a different spacer or two each time you run a batch. Intermittent oscillation.

I don't recall any reports or pictures, so probably not. Although some people had been using routers and/or shapers.

Bummer.

Nah, it isn't difficult. One can buy sheet goods in various thicknesses, so one just stacks and glues.

Yep.