[canman77]

I have no idea where the best place to post this question is, since there are so many subforums where this could be applicable. So forgive me if this is not the right place!

Anyways, I just ordered a Makita RT0701C router to replace my awful DC spindle, and I have some plans for a 65mm spindle clamp. My question is, what are my options for clamp materials? I've seen these clamps made from MDF, HDPE, aluminum...all sorts of material. Obviously aluminum would be the best, but with a 300w DC motor I'm not going to even try milling aluminum. (Seriously, this thing is awful. Tons of flex, very very bad spindle.)

I've got some extra G10 from another project, would G10 make for a decent clamp material? Any other suggestions for materials that would make for a good clamp?

Many thanks!

[LeeWay]

I think G10 may be just as hard on your spindle as aluminum and harder on your bits.
Make a temporary one out of layers of MDF. Then with the new spindle you can update to whatever you think it may be capable of machining.

[canman77]

That's kind of what I was thinking, I just wasn't sure if there was a better way. I have a bunch of router burrs for cutting G10, but the current "spindle" doesn't spin fast enough to effectively cut G10, or so I've been told.

Is MDF suitable for a semi-permanent clamp? I'm not sure how long it will be before I mill a clamp out of something else.

I guess my question should be, what are some materials that will serve as permanent clamps? If MDF will work for a while, I'm all for it. But G10 is super rigid and if that will work, I'd be fine milling that out later on.

In a similar vein, is G10 (1/4" thick) suitable for a mounting plate for the new spindle? The gantry is narrow so I'll need something to mount it to, possibly. Haven't been able to make the proper measurements yet.

[LeeWay]

MDF and permanent should not really be in the same sentence.
I pretty much dislike MDF for just about anything, but sometimes it is a necessary evil.
I would make one out of MDF and consider it to be strictly temporary.
One of the first projects with the new router would be to upgrade the clamp. You can make permanent clamps out of a lot of different material, but I think I would skip the G10.
Just get you a piece of hard maple and go to town with it. It is plenty strong and durable.
From that if you see a need for a better design, then you could step up to aluminum.

[louieatienza]

You can find a paper based phenolic like RichLite, PaperStone, Arborite, Garolite, Tufnol... just make sure it's paper based. Machines as easily as hardwood, without grain tear-out.

The only caveat is that you set you DOCs that you can run as fast as possible to prevent burning the edge.

[canman77]

MDF and permanent should not really be in the same sentence.
I pretty much dislike MDF for just about anything, but sometimes it is a necessary evil.
I would make one out of MDF and consider it to be strictly temporary.
One of the first projects with the new router would be to upgrade the clamp. You can make permanent clamps out of a lot of different material, but I think I would skip the G10.
Just get you a piece of hard maple and go to town with it. It is plenty strong and durable.
From that if you see a need for a better design, then you could step up to aluminum.

Haha, yeah I kind of figured MDF wouldn't be a long-term solution. On the other hand though, I see some pretty interesting CNC machines built from MDF, so I guess some people find it reasonable!

I like the hard maple idea, I hadn't thought about that. Would the maple you can get from Home Depot work, or is that more on the softer side of maple? (I'm never really sure what I'm getting from them as far as "hardwoods" go because they don't give you much information.) There's a local hardwood store I can go to if the Home Depot maple won't be up for the job.

Louie, thanks for the paper-based phenolic idea as well...there's a local plastics shop that carries a bunch of phenolic stuff, I'll look into that as well. I have a sheet of canvas phenolic, but it's miserable to cut, I assume because of really low RPM's and a flexible spindle.

The clamp plans I have don't have any kind of measurement on them (you get what you pay for!) so I'm wondering if you guys can shed some light for me on the diameter of the clamp. Should it be exactly 65mm to match the canister of the Makita router, or should I make it 64mm in diameter? It looks like the open portion of the clamp is maybe 3-5mm wide, so I'm thinking the diameter should be 65mm.

Thanks for all the tips, very helpful for sure!

[LeeWay]

I am sure guys have built machines out of cardboard and bailing wire or paper clips too, but that doesn't mean they worked well.

If the whole machine is built from the detestable MDF, then making the router clamp out of MDF too will likely not be the machines weakest link. Other areas of the machine are likely too weak to show the weakness of the spindle clamp too.

It hit and miss at HD for anything like that. Poplar is a known wood species and is pretty stable across the sizes in HD. HD maple would probably work, but really for getting smaller quantity and exactly what you need, Ebay is a very good source. You may have to buy too many board feet in a local place just buying a single plank.

[canman77]

So the plan is to make two identical clamps (obviously), and if I go with HD wood, I'd make each clamp 0.75" thick (thickness of the boards). (It's a Chinese 3040 machine) My HD carries maple, walnut, a few varieties of oak, mahogany, poplar, and birch, so getting one board foot of one of those woods might work, but if you think those woods might not hold up well, I'll look into the Ebay option.

The local place also has a bunch of scraps lying around I might be able to get for cheap.

I've seen some pictures of plywood clamps, would there be any advantage to plywood over maple (or any other hardwood)?

[wizard]

I think G10 may be just as hard on your spindle as aluminum and harder on your bits.
Make a temporary one out of layers of MDF. Then with the new spindle you can update to whatever you think it may be capable of machining.

Lee has the right idea here. In fact if you have a router coming it might pay to simply build a mount for the router base and use that to make a decent clamp as your first project with the new router,.

I'm a bit concerned about your DC spindle comments. Are you sure all flex comes from the spindle itself?

[wizard]

That's kind of what I was thinking, I just wasn't sure if there was a better way. I have a bunch of router burrs for cutting G10, but the current "spindle" doesn't spin fast enough to effectively cut G10, or so I've been told.

It might not turn fast enough to use burrs as designed but that doesn't mean you can't machine with endmills.

Is MDF suitable for a semi-permanent clamp? I'm not sure how long it will be before I mill a clamp out of something else.

People have done so and have also use Baltic birch plywood.

I guess my question should be, what are some materials that will serve as permanent clamps? If MDF will work for a while, I'm all for it. But G10 is super rigid and if that will work, I'd be fine milling that out later on.

It really depends upon the rest of the machine, there is no sense putting a good and expensive clamp on a machine that doesn't properly support the spindle. If you go the wood route I'd prefer a plywood over MDF myself.

In a similar vein, is G10 (1/4" thick) suitable for a mounting plate for the new spindle? The gantry is narrow so I'll need something to mount it to, possibly. Haven't been able to make the proper measurements yet.

You aren't filling me with a lot of confidence that the rest of the machine is as stiff as it needs to be. I wouldn't use 1/4" plate, made out of any material, to mount a spindle. At least not flat stock, channel iron or similar materials would work though.

[canman77]

No, not all the flex. There's a bit of flex in the tool as well, but I'd expect that from any tool with a smaller diameter.

For example, when I run a standard end mill (1/4") through a piece of pine or some cedar I had lying around, the bit screams when running at 1000mm/min, 8kRPM (max RPM on this spindle). When I slow the feed rate down, it continues to scream, until I get to around 3-400mm/min, at which point, the bit doesn't make a continuous cut. It will cut (and still scream), stall for a second, and jump ahead. I can see the end mill vibrating terribly, and when it jumps, I can see the shaft above the collet on the spindle flexing. I've been told this is because there isn't a bearing right there on these cheap DC spindles. I have no idea if that's correct, I'm fairly new to all of this. I'd like to think at the proper RPM, the bit wouldn't stall and jump like this at lower feed rates, and that the cuts would be much smoother.

If I increase the feed rate to 1100 or 1200mm/min (or higher), the chatter just gets worse. It's not a scream that you'd expect when cutting wood, the end mill vibrates something fierce. Horrible tool chatter.

The gantry is very rigid. What's concerning to me is that I can actually see the DC motor spindle moving above the collet when these weird jumps happen.

[LeeWay]

I was going to mention too, that the way you make the clamp will really determine the tolerances for it.
I usually do two piece clamps and then on the moving jaw, I make is less than half circle. In others words I leave a gap where the clamp jaw has room to move in and out.
For the spring type holders, you would want one with closer tolerances because it will be clamping pretty much all the way around.

Hard to see in this picture, but there is about a 1/4" gap between the front and rear halves of the aluminum clamps on my plasma cutter. Setup with a floating head design.



Then here is what I did on my old shop made router.

[canman77]

I've got it designed as a spring clamp right now, but I may change it to a floating head design, because the spring clamp design is about 15mm wider than the gantry and would prevent full movement of the x-axis.

I'll update with pictures as I make progress! Thanks again for the tips and suggestions, very helpful.

[canman77]

Well, I ended up going with white oak because it's only slightly less hard than maple on the Janka hardness scale. Everything was great until I tightened the clamp too much and part of the clamp snapped. Most unfortunate. I suppose have a grain is one of the drawbacks to using wood. Easily splits along the grain.

[Devastator]

I wouldn't have any reservations about using MDF or plywood for your spindle clamp provided that it is about four times as thick as aluminum and is fully sealed and painted. I've attached a photo of my plywood based clamp. Basically a giant block with knurled screws that thread into dowel nuts to tighten.

[canman77]

Do you run into heat issues with that clamp? The Makita got pretty warm after 30 mins of cutting. I'm wondering if a clamp like that would cause the router to overheat.

I like that design though. Very simple, no need to cut it on the machine.

Assuming I make clamps from aluminum, would 1/2" aluminum work? (There would be 2 clamps, top and bottom)

[Devastator]

Do you run into heat issues with that clamp?

Nope, router runs cool. Even when I run it for 16 hours straight. I do have a SuperPID on it though.

[canman77]

Interesting. I'm a little concerned about the Makita heat. I've been told the feeds/speeds can make a difference in the heat though. I ran it at 30kRPM and fed it through white oak at 1500mm/min...would that cause the router to get hot? It wasn't burning hot, but it was definitely hotter than "warm."

I've also heard routers sometimes need to be broken in because the bearings are so packed with grease. Once they are broken in they run cooler, or so I've read. Does that sound right?

[Devastator]

Heat is directly related to feeds and speeds and DOC. I just listen to the loading. If it sounds like it is struggling I back off. I never run the maximum RPM because the SuperPID would have no way to increase amperage when under load. If you listen to your motors, they will last a long time. I'm at about one dozen bearing changes for my router. I do notice it is slightly warmer around the lower bearing after a change out, but not by much. I think with a real spindle where you need to preload the bearings it would be more noticeable.

[canman77]

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

The router wasn't really struggling, or at least it didn't sound like it. The problem is, I don't have a reference point for what is/isn't normal sounding vs. somewhat not normal. I can definitely pick out bad noises...machines are loud, but if it's absolutely screaming, that's probably not good, haha.

I only did 2mm DOC, so I don't think I was pushing the machine too hard, but maybe that was a bit much for the router.