Modifying a Multi-Function Machine

Is there a way to make the shaper on a combination woodworking machine spin fast enough to use router bits. January 27, 2007

I've got a small studio furniture shop, and my main piece of power equipment is an SCMI/Mini Max 5-function combination machine. One of those functions is a full size 1 1/4" spindle shaper. To make the machine more attractive to artsy small-shop guys like me, they stuck a router collet on the top of the spindle. The only problem is that the top speed is around 9500 RPM, appropriate for big shaper cutters, but lousy for the little router bits I'm used to using. In fact, I don't own a single shaper cutter, largely because the 1 1/4" bore cutters start around $100.

I basically need my shaper/glorified router table for simple rabbeting and slotting; I do very little with fancy molding shapes. What is the best/cheapest way to get good results from this machine?

It's belt-driven, so I might be able to have a customized pair of pulleys made, but I don't know whether the bearings are up to higher RPMs. Perhaps I could have a machine shop make a 3/4" spindle with a 1/2" shank that would fit the router collet, so I could use more modestly priced shaper cutters? Any other ideas? By the way, I don't have room in my shop for a router table.

Forum Responses
(Solid Wood Machining Forum)
From contributor M:
If your shaper spindle is removable, what some of the Felder guys have done is make an insert that drops into the cut out in the table and mount a router on the insert and not bother with the router spindle at all.

Idea # 2 would be just take a 1/2" spindle and insert that into the router spindle and use T bushings for your 3/4" shaper cutters. Just make sure they are rated to handle the higher RPM's. Spindles for that application can be found off the shelf from someone. Sorry, I don't have a name for you at the moment.

After a while, though, you'll find yourself using the larger 1-1/4" tooling, as it gives you a much better cut. If you are ever considering buying a cope and stick set of cutters to make doors, buy the larger ones to run on your shaper and not the smaller ones - you'll get a better job off them.

From contributor D:
I would suggest you adapt yourself to the shaper, since it won't change much. Invest in some real shaper tooling and use the machine as it was really designed - as a shaper. Once you learn the basics (no different from a router table), you will get better, more accurate cuts, with less noise and vibration, more power and control, and you will gain confidence. Shapers are superior to routers in almost every stationary situation. You may even think about a power feeder, the best friend a shaper - or woodworker - ever had.

Your assessment of the marketing reasons for the router spindle is accurate. You are trying to make the shaper do something it cannot do well.

If you cut rabbets, get an aluminum rabbetting head with carbide inserts and spur cutters, maybe a bearing or two, and learn to use fixed bearing points if you do curved work. Get two and make tenons in one pass. Some basic tooling, a little experimentation and creative thinking go a long way.

From contributor J:
If you're doing mostly rabbetting and slotting, wouldn't it be cheaper to buy a couple rabbeting bits than having a machine shop custom make parts for your machine? If the budget is tight, you can still get two slotting cutters from Grizzly for $100. I try to buy the cutters I need when I need them for a specific job. That way I can tack the cost of the cutter to that job.

I'm not an engineer, but I don't think doubling the speed (router bits spin at around 20,000 rpm) of the spindle would be a good idea. The bearings are probably not designed for that type of speed. And if I understand your other idea correctly, you want to put a 3/4" bore cutter onto a spindle which would mount into a 1/2" router collet? I have to say that one makes me cringe.

If you want to get good use out of the machine with a wide array of cutters and don't mind having parts machined, I think you're better off replacing with, or having the bigger spindle machined down to, a 3/4" size. That seems like the safest bet. But if you're only going to use a couple of cutters, I think cost-wise you're better off just buying the 1-1/4" cutters and getting to work.

From the original questioner:
Thanks so much for the ideas so far. A problem with trying to switch over to shaper tooling (besides cost) is that many smaller profiles seem unavailable. I spent an hour or so Googling around last night and the thinnest shaper slot cutter I found was 7/32". I often need to cut slots around half that thickness. The rabbeting heads do look attractive, though.

Contributor J, I wasn't thinking of pushing the RPMs up quite that far. The school I went to (Redwoods) has a couple of nice European shapers that turn around 14 or 15k and do a decent job with router bits. I'm not thrilled either about the 3/4 spindle-in-router-collet idea, but it is a nice, beefy collet and I generally don't hog off a lot of material at once.

From contributor J:
If you're doing a lot of work with that particular size, there are two possibilities that come to mind.

1) Could you use your table saw instead? Sounds like you're at about 1/8" for your slots, which would be easy for a table saw blade.

2) Call Magnate or check them out online. I buy tooling from them and they make slotting cutters from 1/16" kerf. They only have 5/16" bore as a stock item for these cutters, but they do make custom tooling. They could likely make exactly the size you need, if you use it enough to justify the cost.

From contributor R:
I don't see why you couldn't get more RPMs from the bearings. Shapers typically have a higher grade bearing than you find in a router. If your machine is three phase, then using a VFD to double the speed is simple and relatively inexpensive. If the machine is single phase, then the VFD won't work. I would be a bit concerned that the router collet is at the top of a shaper spindle for whip. Having the spindle turned down sounds like a better solution overall. No room for a router table?

From the original questioner:
"No room for a router table?"

I know, freakish isn't it? Imagine a combination machine that includes a 12" TS with slider, 12" jointer/planer, horizontal mortiser and shaper, plus an 18" bandaw, 12" disc sander and an old fashioned European-style bench, all in a single-car garage. I have enough trouble finding a place to put materials and an in-process project as it is. Those gigantic two-car garages are starting to look pretty good. : )

From contributor R:
I should have explained the VFD better. Variable Frequency Drive is the full name and it will allow a three phase motor to run on single phase. It can double the motor's rated rpm as well as give infinitely variable speed and many other bells and whistles. Older motors may not be suitable, but most modern lathes are using the technology.

From the original questioner:
Thanks. The VFD idea sounds great, but I'm stuck with single phase.

From contributor B:
First, you don't want to run a motor at higher than its rated RPMs. Definitely looking for trouble there. Plus, I don't really think a variable frequency drive allows you to go faster than the motor's rated RPM speed. Instead they allow you to slow it down below that speed.

Second, you could purchase the largest diameter straight cut 1/2" shank router bit you can find. The further away from center, the higher the sfm speed will be. There is less cutting power out there, but that won't be a problem on the combination machine.

Third, no room for a router table? All you need for a router table is a hand router and a piece of MDF, particleboard or plywood. Cut a hole in the middle and mount the router base. When not in use, remove the router (leave a spare base on the board if you have one) and hang the board on the wall or store it behind something.

From contributor I:
Maybe buy yourself a 1 1/4" bore corrugated insert knife head, and have steel knives ground to whatever profiles you want. I think you can get them coated for longer runs, but should be fine in HSS for solid wood.

From contributor R:
There are definitely VFD drives that will double a motor's rated rpm. This is not speculation on my part but real personal experience. Also, on motors 1 hp and under, there are VFDs that will operate on 120 volts and will allow a 240 volt three phase motor to run. My local motor repair shop sells a Baldor VFD that does exactly that. They have one set up on a small drill press.

On older moulders it was common to have a frequency converter to double the motor's rpm. On occasional use it should be no problem at all to kick a standard motor's rpm up. Again, advice from my local motor repair guys. They are very knowledgeable on anything motor and control related.

I still find it hard to believe there is no room for a router table in a small shop!

From contributor T:
Seems like you are getting a lot of great ideas here. I would like to throw in a couple of ideas not heard yet. In regard to speeding up your machine, you might check with some local electronics companies about a PWM motor upgrade. One of my customers upgraded his shaper with one of these systems, which allowed him to get infinite variable speed. PWM stands for Pulse Width Modulation, and it uses a DC motor and a control unit to send pulses to the motor at a controllable rate. The faster the pulses, the faster the motor spins. The great thing about these systems is that they use a feedback system that adjusts the pulse rate to compensate for load. This means that no matter what you're cutting, within reason, the spindle RPM's won't change. The only thing you need to be sure of is if your bearings can handle higher speeds.

Now, onto shaper cutters. If you need shaper cutters made with thinner kerfs, we (Lemmon & Snoap Co., Inc.) can help you. We can use saw plate to make groove widths down to 1/16" if need be. The saw plate is more rigid for stability.

From contributor L:
Make a router table for small machining. An 1 1/4" shaper (and powerfeed) are very effective tools allowing you to expand your abilities greatly. Check out the index rebating heads from Bimex. They also have corrugated heads that you can grind your own patterns for. It's relatively easy to learn to grind HSS and opens up an entirely new range of possibilities.

From contributor K:
This may not be applicable to your combination machine, but I have had good success with bolting an old unisaw table wing (9" w) machined to accept a router to the backside of a medium duty shaper. That gave me the RPM's of a cheap router body mated to a stable platform mounting a powerfeed for grooving and small profile shaping tasks.

From contributor P:
If you really want to use 3/4" shaper cutters, why not buy the 3/4" spindle from MiniMax for your machine and switch it out? Yes, it's expensive, but it will pay for itself shortly in reduced tooling costs. Surely it would be cheaper than having a custom one made by a machine shop.