Shaper rotational speed and feed rates

[mark mcfarlane]

Hi Mark, a couple of things. The head is actually 125 mm in diameter, which might change the math a little bit if you use the spreadsheet (not much) , but what's important is that the critical diameter is the cutting circle diameter with the knives installed. So that's 125mm with just the little carbide rebate knives, but a lot more with HSS knives installed. You'd have to measure, but you're probably in the 165mm to 175mm range.

The RPM ranges for your machine are very strange. I think what MiniMax did was make it work well for European 50hz power (those RPMS are more typical) but instead of making new pulleys/motors for North American markets, they just used the same motor/pulley arrangement and allowed the RPMs to crank up and be kinda useless. The RPM range for that head are very typical of what you see, and if your machine had the 7000 RPM option, it would be right smack in the middle of the chart.

B

Excellent point on the difference between head diameter and cutting diameter, thanks Brent.

I also assumed they used the same pulleys and get a different RPM on 60Hz.

At the end of the day, since I am not a production shop, I guess its not really a big deal to just run at 4200 RPM and slow down the feed rate. For someone in a commercial hurry, this weird pulley design choice might make a more significant difference.

Based on the documentation on the CU300, the US market is kind of an afterthought. Even the way the manuals are organized is weird, and some things either don't translate well or the Italian documentation also sucks.

In SCMI's credit, I have received decent support from SCMI USA when I have called with 2 problems, and my sales guy (Sam) has been exceptional. I had an SCMI tech correctly diagnose that one of my two 120V leg fuses for the spindle moulder was blown by listening to it try to start up over the telephone. The whole conversation took 5 minutes and a new fuse was on its way for free.

[Rod Sheridan]

Rod, in the pdf file, are the b=xxx curves the 'cutter length', and for an insert head, is the cutter length the height of an insert blade, or is it the total path length measured along the cut profile?

Hi Mark, that's the height of the cutting tool, so the knife or insert.......Rod.

[Rod Sheridan]

... and the charts from Eric Stephensn's Spindle Moulder Handbook indicate that running a 120mm diameter head at 4200 RPM is suitable for cutting: nothing.

Attachment 391701Attachment 391702

Mark, you're correct.

125mm at 4,200RPM is 27.5 m/s, far below the 40m/s minimum.

The 50Hz speeds would be ideal. You should see if the manufacturer can supply a different motor pulley............Rod.

[Tom Bender]

14,760 ft/min

Remembering that some places in the world they switch . and , this can work out.

[mark mcfarlane]

FYI, the HSS inserts cut the rebates I needed in MDF very cleanly at 125mm. Haven't cut the T&G profiles yet in maple, but the grooves came out acceptable in my pine prototype.

With the T&G inserts installed in the Whitehill steel limiter head, the diameter is 158mm to the tips of the tongues, so for 4200RPM and 158mm (6.22 in) I get a knife speed of 6045 ft/min = 1842 m/min, = 30.7 m/sec which is getting a little closer to your minimum.

It appears, for my CU300, I should have just purchased the Amana 88 or 100mm non-limiter aluminum heads, which are rated to run at 9000RPM max, so I could run them at 8400 on my Minimax CU300.

I'll probably eBay off my Whitehill head after this project is finished and go with the much cheaper Amana setup. I didn't do enough research before buying the Whitehill head and later learning that I can only run it up to 7000 RPM. On my screwy Minimax at 60Hz (which allows 4200, 8400, and 12000) that means I have to run the head at 4200. A $350 mistake on my part.

I don't see changing pulleys on the Minimax as a valid option. I'd probably buy a new shaper first.

If I factor in the price of the DC40, smart stand, and steel limiter head I am in for ~$3K and 3 weeks past my deadline. The doors will come out fine, and I learned a lot, but a $100 router bit set probably would have done this job.

Yet..., it is enjoyable feeding stock into a power feeder .

[brent stanley]

Gee, that's too bad it didn't work out. The problem is, the odd RPM options are going to keep coming back to haunt you I think and reduce flexibility perhaps. If you look on the charts, the 7000RPM would have put you right smack in the middle of everything and been perfect......probably why MiniMax designed it that way.

[Warren Lake]

Nanny state fail. I posted the birdseye cabinet back. Wrong speeds by far perfect results.

[Rod Sheridan]

Gee, that's too bad it didn't work out. The problem is, the odd RPM options are going to keep coming back to haunt you I think and reduce flexibility perhaps. If you look on the charts, the 7000RPM would have put you right smack in the middle of everything and been perfect......probably why MiniMax designed it that way.

Yes, that's why every machine has about the same RPM ranges, just like stock feeders, most have similar feed speeds........Rod.

[brent stanley]

Yes, that's why every machine has about the same RPM ranges, just like stock feeders, most have similar feed speeds........Rod.

Exactly my point.

Mark, since your machine only has three speeds, can I assume that your motor only has one pulley on it, and your spindle has three, or the other way around? You may find that if the motor only has one, it might be cheap and easy to get another pulley from any source to replace the stock one and give you better options. Just might cost you less than the hit You'll take selling your new head used.

Really is worth looking into in my (our?) opinion.

B

[mark mcfarlane]

Exactly my point.

Mark, since your machine only has three speeds, can I assume that your motor only has one pulley on it, and your spindle has three, or the other way around? You may find that if the motor only has one, it might be cheap and easy to get another pulley from any source to replace the stock one and give you better options. Just might cost you less than the hit You'll take selling your new head used.

Really is worth looking into in my (our?) opinion.

B

Unfortunately the motor and spindle each have 3 pulleys. The distance between pulleys at the center pulley is ~ 1 inch. Belt is a 'multi v-groove belt'. I don't see any convenient way to swap pulleys short of having a custom 3-pulley assembly made, or putting a single pulley on one side and be stuck at a single speed, or change pulleys to change speeds, which is fairly ludicrous.

I'm guessing most other US 60Hz Minimax CU300 users are using the Amana or similar US-made heads that can handle 8400 RPMs, otherwise this issue would have cropped up on SMC in my research/searches.

[Mike Cutler]

If I factor in the price of the DC40, smart stand, and steel limiter head I am in for ~$3K and 3 weeks past my deadline. The doors will come out fine, and I learned a lot, but a $100 router bit set probably would have done this job.

Mark
I think in a very short time, you won't feel the same way.
That's a quality machine you have there. As soon as you get past this learning curve for the cutter heads behind you, you'll be off and running.
That Whitehall is a nice block. What was the lead time for it, if you don't mind my asking?

[brent stanley]

Unfortunately the motor and spindle each have 3 pulleys. The distance between pulleys at the center pulley is ~ 1 inch. Belt is a 'multi v-groove belt'. I don't see any convenient way to swap pulleys short of having a custom 3-pulley assembly made, or putting a single pulley on one side and be stuck at a single speed, or change pulleys to change speeds, which is fairly ludicrous.

I'm guessing most other US 60Hz Minimax CU300 users are using the Amana or similar US-made heads that can handle 8400 RPMs, otherwise this issue would have cropped up on SMC in my research/searches.

I had my head inside a cabinet I'm installing (that I made using one of those heads!) thinking about your situation and realized you were probably in a pulley situation as you describe......

[Jared Sankovich]

I run my 120mm amana head at 5100 (I have 3600, 5100, 8000 and 10,000) I've run it at 8000 (max is 7900) and honestly the finish is just as good at 5100 and it doesn't sound like it's going to take flight. A lot of hss heads are run at 4 to 6k. The small tenoner cope heads run at 4k something and all seem to do well.

Though if you want out from the Whitehill head im sure someone here would buy it... i know I would

[mark mcfarlane]

Mark
I think in a very short time, you won't feel the same way.
That's a quality machine you have there. As soon as you get past this learning curve for the cutter heads behind you, you'll be off and running.
That Whitehall is a nice block. What was the lead time for it, if you don't mind my asking?

I'm sure I'll be less frustrated when this project is completed, and maybe even someday love the shaper. The stock feeder did an awesome job controlling the wood for near perfect, effortless groove cuts.

I don't remember the exact delivery time of the Whitehill combi head to my home, but it was somewhere around 10 days after I paid. It came before the '2 weeks' that the sales person suggested. The combi head came in a plastic case that will hold maybe 8 sets of knives/limiters and with a T-handle hex wrench for the wedges.

The combi's rebate feature with it's corner 'knickers' cuts really smooth and crisp in plywood and MDF (all I've tried so far). A much better cut than I have ever made on my fancy/shmancy 3HP router table.

And I've only nicked myself once on the shaper tooling so far, before deciding that the gloves everyone wears on Youtube really are a good idea. The Whitehill combi head with inserts has 8 blades: profiles, limiters, rebate, rebate corner knickers,... A couple pounds of steel with sharp edges all over the place.

[Phillip Gregory]

I have the 120 mm Amana head on my direct drive Whitney shaper that runs somewhere around 7000 rpm (120 Hz on a 2 pole motor.) 7000 rpm is a good speed on that head and works well. You typically want to run a head near the upper end of its rated RPM range if possible for better surface finish and maximum feed rate, but you cannot exceed the maximum rated RPM or you risk things flying apart which is very bad news.

If I were you, I'd get the next smallest size head (100 mm) and run it safely at 8400 rpm. That would be the easiest option as you can use your existing knives and limiters, and heads are not all that expensive.

The other option would be to replace your single phase motor with a 3 phase motor and run it off of a VFD. Running your motor at 50 Hz would put the spindle speed right where you want it for the 125 mm head.