[Devastator]

OK, so it sounds like I ran the RPMs too high. For wood, 18-20kRPM would be sufficient, yeah?

Depends on your feed. I personally would back down on the feedrate so you can run the router between 15 to 18K RPM. I don't like the noise at full RPM and stock router bearings are rarely rated for full speed for extended periods.

[canman77]

I'll give slower RPMs a shot. Probably should order some new end mills too...a single flute and a two-flute should open up a few more possibilities.

Is there anything wrong with using HDPE for clamps?

White King Starboard 1 2" x 6" x12" Polymer HDPE Sea Plastic Sheet | eBay

[Devastator]

Is there anything wrong with using HDPE for clamps?

I would think that quality plywood would be more rigid and cheaper. Without knowing structure of your machine it may all be a moot point. It may not matter what material you choose if the machine design is not as good as the mount. It only has to be more rigid than the next weakest component.

[louieatienza]

Take some of the guesswork out of figuring speeds and feeds and learn the very basic formula:

Feedrate = number of flutes x chipload x spindle RPM

The chipload is the manufacturer recommended. Usually they will give you a range, so you pick the lowest number to start. You'll set your axial DOC (cur depth) and radial DOC (stepover) based on your machine's rigidity. (experimentation needed.)

As you can see from the formula, the higher the RPMs, the faster you have to run the machine. You have to work in reverse: figure out what speed you can run your axes, then divide that by the number of flutes and chipload to get the spindle speed you should be at. Then, you can tweak the spindle speed. A cool trick I got from Ron Reed at PreciseBits is to "feel" your spindle as it's cutting. Then lower or raise the RPMs slightly. You'll feel a "sweet spot" where the vibrations are greatly reduced. You then take note of the spindle speed, federate, DOCs.

Also, "noise" is not always the best indicator of what's going on. The best test is to look at the quality of cut. If I had to hazard a guess do you have one of those eBay spindles that look like a DC motor with a collet attached to the end of the motor arbor? It's likely these things don't have bearings that take much thrust loads, and probably have a bit of axial play in them. To note, neither do routers, and you should learn to program using ramp or helix-in to minimize axial loads. Also, use the shortest tool possible that will still cut at the depth you need. And don't cheap out on bits and tools. The cheaper stuff I find are not ground as well, out-of-size, and crappier grade carbide (you can actuall feel the heft of a quality carbide tool.)

- - - Updated - - -

I'll give slower RPMs a shot. Probably should order some new end mills too...a single flute and a two-flute should open up a few more possibilities.

Is there anything wrong with using HDPE for clamps?

White King Starboard 1 2" x 6" x12" Polymer HDPE Sea Plastic Sheet | eBay

It can be slippery stuff...

[canman77]

Take some of the guesswork out of figuring speeds and feeds and learn the very basic formula:

Feedrate = number of flutes x chipload x spindle RPM

The chipload is the manufacturer recommended. Usually they will give you a range, so you pick the lowest number to start. You'll set your axial DOC (cur depth) and radial DOC (stepover) based on your machine's rigidity. (experimentation needed.)

As you can see from the formula, the higher the RPMs, the faster you have to run the machine. You have to work in reverse: figure out what speed you can run your axes, then divide that by the number of flutes and chipload to get the spindle speed you should be at. Then, you can tweak the spindle speed. A cool trick I got from Ron Reed at PreciseBits is to "feel" your spindle as it's cutting. Then lower or raise the RPMs slightly. You'll feel a "sweet spot" where the vibrations are greatly reduced. You then take note of the spindle speed, federate, DOCs.

Also, "noise" is not always the best indicator of what's going on. The best test is to look at the quality of cut. If I had to hazard a guess do you have one of those eBay spindles that look like a DC motor with a collet attached to the end of the motor arbor? It's likely these things don't have bearings that take much thrust loads, and probably have a bit of axial play in them. To note, neither do routers, and you should learn to program using ramp or helix-in to minimize axial loads. Also, use the shortest tool possible that will still cut at the depth you need. And don't cheap out on bits and tools. The cheaper stuff I find are not ground as well, out-of-size, and crappier grade carbide (you can actuall feel the heft of a quality carbide tool.)

- - - Updated - - -



It can be slippery stuff...

Very informative post, thank you! I have been messing with the basic formula, but every time I try and make calculations, I get stuck on the chipload, because I have no idea where this 4 flute end mill came from. Probably time to invest in some decent end mills. I know with fewer flutes, you can "compensate" for the stepper motor lack of speed. I can probably get rapids of 3000mm/min, but I keep them at 2500mm/min to avoid all chance of stalling. I've been cutting material at 1500mm/min with confidence, but could probably do 2000mm/min depending on DOC, etc. So clearly, the machine doesn't go as fast as the formula says it needs to with a router going 10-30k RPM. I assume this is one of the reasons why single and double flute end mills are around!

Now, onto the spindle. Your guess is 100% correct, a crappy chinese DC motor with a collet attached. Certainly no bearings. However, the router that I have appears to have bearings to take the axial load. I think. I'm not certain, so take a look at the parts diagram: http://makitatools.com/en-us/Assets/...RT0701C_PB.pdf

It looks like there's a bearing right at the base near the collet. That would take some of the load wouldn't it?

Onto the tools...this guy sells a lot of Kyocera stuff: items in store on eBay!

Are these tools any good, or should they be avoided? I can't see on the listing what the recommended chipload should be, but maybe I need to find that directly from the manufacturer.


Regardless, thank you for an insightful post, I really appreciate it. I'll look into making a couple of clamps from plywood, all the glue reinforcement from each layer of wood sounds better than solid wood with weak spots in the grain.

[Devastator]

Onto the tools...this guy sells a lot of Kyocera stuff: items in store on eBay!

Are these tools any good, or should they be avoided?

I buy most of my endmills from drillman1.

[LeeWay]

I like Kyocera end mills. I have been using the 1/8" ones for quite a while now. Priced right. Very sharp. I get a good finish with them.

[canman77]

Awesome! My question now is, where can I find the recommended chipload? I looked all over last night for information from the manufacturer but couldn't find anything. Do these tools just follow "standard" chipload recommendations?

[louieatienza]

For plywood you can use about .002" for 1/8" tool and .004" for 1/4" tool. Koyocera makes excellent tools.

[louieatienza]

For plywood you can use about .002" for 1/8" tool and .004" for 1/4" tool. Koyocera makes excellent tools.

I own the same Makita router, though use it for manual work. Runs real smoothly though. They usually have deep groove radial bearings that can take some axial load, but still - you'll save the bearings longer if you ramp or helix in whenever possible.

[canman77]

Yeah I'll ramp/helix from now on...I read somewhere that with wood you can plunge, but I didn't think about the load on the bearing.

I'll use those chipload numbers, thanks! Are these from trial and error or did you find Kyocera chipload recommendations somewhere? Also, I tend to use mm since I have Mach3 set to mm...is it ok to convert the .002" to .0508mm, or is that usually not a good idea? (Not sure why it wouldn't be OK to do, but you never know)

[louieatienza]

Yeah I'll ramp/helix from now on...I read somewhere that with wood you can plunge, but I didn't think about the load on the bearing.

I'll use those chipload numbers, thanks! Are these from trial and error or did you find Kyocera chipload recommendations somewhere? Also, I tend to use mm since I have Mach3 set to mm...is it ok to convert the .002" to .0508mm, or is that usually not a good idea? (Not sure why it wouldn't be OK to do, but you never know)

I'd still ramp or helix. The tip of the tool is the most inefficient part.

As the industry standard for chipload is in inches, it's not too hard to convert afterwards. Chiploads I gave are pretty standard for hardwoods at those sizes and averaged out. But it's far better than guessing and crossing fingrrs...

[canman77]

Awesome, I'll give those chiploads a shot this week when I machine some new plywood clamps. Also good to know that the chipload number is OK to convert to mm.

[louieatienza]

Awesome, I'll give those chiploads a shot this week when I machine some new plywood clamps. Also good to know that the chipload number is OK to convert to mm.

For sake of ease, I'd do all the calculations in inch first, then convert your solutions to mm, to avoid any errors in conversion.

[canman77]

For sake of ease, I'd do all the calculations in inch first, then convert your solutions to mm, to avoid any errors in conversion.

Will do, thanks! Meant to reply yesterday and ran out of time. I'm hoping to get some new clamps made from plywood in the near future, I'll post back here for anyone in the future who is looking at making clamps from plywood I guess.

[wizard]

Yeah I'll ramp/helix from now on...I read somewhere that with wood you can plunge, but I didn't think about the load on the bearing.

Only if your tool supports center cutting. This is especially the case with router bits designed for wood as some of them don't have anything at all in the center to cut with, you have to ramp in. Beyond that even cuter cutting end mills vary in the load they put on bearings. In wood I wouldn't go anymore than two flute if plunging was the order of the day.

I'll use those chipload numbers, thanks! Are these from trial and error or did you find Kyocera chipload recommendations somewhere? Also, I tend to use mm since I have Mach3 set to mm...is it ok to convert the .002" to .0508mm, or is that usually not a good idea? (Not sure why it wouldn't be OK to do, but you never know)

Convert away. Personally I like to work in the metric system myself.

In any event do go to the web site of your selected tool manufacture and download his catalogs. They will have all sorts of information on their cutters including feed rate info. Of course sometimes this means information for aluminum or steel. Even when machining aluminum you will find a range of feeds per tooth specified. Generally you try to balance tool wear against surface finish. Going slow leads to more tool wear but improves surface finish. If you are machining woods subject to burning you really need to lean towards faster feed rates as opposed to slower ones.

[wizard]

For sake of ease, I'd do all the calculations in inch first, then convert your solutions to mm, to avoid any errors in conversion.

How is that any easier?

[Jon.N.CNC]

would it not just be easier / possibly cheaper to buy one?
65mm Diameter Spindle Motor Mount Bracket Clamp | eBay

Edit: get the feeling this is irrelevant now. People always tell me i need to get with the times.

[canman77]

would it not just be easier / possibly cheaper to buy one?
65mm Diameter Spindle Motor Mount Bracket Clamp | eBay

Edit: get the feeling this is irrelevant now. People always tell me i need to get with the times.

No, certainly still relevant! The problem with the existing clamp is that it interrupts the x-axis movement...it extends well beyond the z-axis truck. Which isn't a HUGE deal, but I'd prefer to get the most out of the machine as possible. By creating my own, I can bring the spindle out a bit further from the truck and the clamps have clearance from the side walls. If that makes sense.

Regarding ramping...my tools do support center cutting. But I think I'll still stick to ramping, unless using a really soft material. Don't want to strain the router too much! I also know when using wood to use faster feed rates, but I can only get the machine to go so fast with the motors/power supply I have (the drivers are excellent at least!) so I'll likely have to start using single or two flute tools to compensate for the limited feed rates.


I probably won't get around to making plywood clamps until next weekend...we're moving the machine to a shed we're building. The sawdust is getting everywhere...doesn't make sense to have the machine in the house! Now we'll at least have a decent place for it.

[Jon.N.CNC]

No, certainly still relevant! The problem with the existing clamp is that it interrupts the x-axis movement...it extends well beyond the z-axis truck. Which isn't a HUGE deal, but I'd prefer to get the most out of the machine as possible. By creating my own, I can bring the spindle out a bit further from the truck and the clamps have clearance from the side walls. If that makes sense.

Regarding ramping...my tools do support center cutting. But I think I'll still stick to ramping, unless using a really soft material. Don't want to strain the router too much! I also know when using wood to use faster feed rates, but I can only get the machine to go so fast with the motors/power supply I have (the drivers are excellent at least!) so I'll likely have to start using single or two flute tools to compensate for the limited feed rates.


I probably won't get around to making plywood clamps until next weekend...we're moving the machine to a shed we're building. The sawdust is getting everywhere...doesn't make sense to have the machine in the house! Now we'll at least have a decent place for it.

I see, in which case I would be considering using acrylic if you're router is not plywood already that is. Ply looses is rigidity in small brackets. Especially in a shed where the humidity might be higher at certain points of the year, you could find the bracket twists.