How many of you have had clamping methods hit by the router/spindle bit?

1968 Views 20 Replies 12 Participants Last post by 4DThinker, 6 mo ago

MarkJonesRanger

Discussion Starter · 8 mo ago

After watching hundreds of youtube videos I have noticed including myself tons of clamping methods that have nicks and broken bits from the router going over the clamping method.

I think I have broken 5 bits in 3 years now. I am learning slowly and haven't broken a bit in a year.

I think the reason for this success is I use brass screws for my first batch run. I put two layers of 3/4" MDF over my aluminum table and then put a 1/4" thick piece of plywood over that to cut into. The 2 layers of MDF generally just get screws or nails into them. I use more screws than clamps.

Also have started using 28 gauge pin nails to tack stuff down in half inch plywood where the pin holes don't matter when I pull them out. Bits do not seem to be affected when they hit them.

I use a lot of the 1/4" plywood to make jigs to position batch work into. Plaques, Lanterns, canteens, wooden coins etc. Made a bunch of 1/4" cams that I screw down on these jigs that also screw into the 2 sheets of MDF.

I am learning slowly. 42 years (now retired) of intown utility work driving with out any at fault accidents has taught me to clear that stuff you might hit out of the way before you hit it. (don't ask my wife what I about hit with the rv a month or so back)

I have a video on youtube where I was cutting a key hole slot from a tap file from last year and I didn't pay attention to the start point...I thought it was the middle of the plague and bam I was saved by a brass screw that took the key hole slot cutter and gave up the ghost.

Those "great scott" moments when something goes aria. Keep me looking with interest.

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difalkner

· #2 · 8 mo ago

I've hit wood clamps once or twice but just a glancing blow so no broken bit. I hit a screw once and that was enough to suitably dull the bit but it didn't break.

Reactions: 1

UglySign

· #3 · 8 mo ago

Recently had a ¼" compression taken out from a pin nail.
Sent a job once and didnt realize it was going to cut out a screw head.
That was wild as I was across the room.

MrChad

· #4 · 8 mo ago

I've hit my clamps a few times but luckily never broken a bit from it.
I started making my clamps out of HDPE cutting boards. Now if I do happen to hit one, it's like cutting butter.

Reactions: 1

4DThinker

· #5 · 8 mo ago

I suspect avoiding clamps requires learning from experience. That's been my personal experience anyway. The clamping strategies I've used over the years always point out their unanticipated flaw(s). I've gone from sacrificial wood clamps of my own design to C-clamps which will always win encounters with spinning bits. The sacrificial clamps I treated with no respect or forethought. The C-Clamps force me to triple check my toolpaths to make sure they aren't in the way.
4D

Reactions: 1

asah

· #6 · 8 mo ago

newbie question: is this dangerous? my router's bit is not protected behind any kind of shield, so if it breaks wouldn't it go flying (towards me...)? Festool OF 1010

gdonham1

· #7 · 8 mo ago

I use painters tape and superglue more and more. I put the tape on the spoilboard and on back of the wood. I use Titebond medium super glue.

Larger projects are harder to use the tape and I use cam clamps.

Here are some pictures of the superglue method and the cam clamps. With either you dont have to worry about hitting any clamps. The cam clamps are low enough I can have my retract height set low which speeds up machining.

Table Wood Automotive design Flooring Floor

Liquid Wood Drinkware Laboratory equipment Gas

Wood Gas Circle Office ruler Electric blue

Wood Sleeve Font T-shirt Art

I use an L bracket to initially position the material on the spoilboard. Then I remove the L bracket and replace it after the cut is done. I squared the L bracket with the router bit and tighten it down.

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old55

· #8 · 8 mo ago

Welcome to the forum @asah

MarkJonesRanger

Discussion Starter · #9 · 8 mo ago

I was carving some cedar plaques 13 of them and getting the key hole slot cut in the raw plaque blanks backs and used a old keyhole.tap file from last year and didn't check the home position. I thought it was center of the plaque ..... next thing I knew when I ran the tap file on the cnc it hit a brass screw that was holding one of my cam clamps down. That brass screw saved my bit. I then located the correct keyhole.tap file and all was good. It happens so fast.

4DThinker

· #10 · 8 mo ago

Cam side clamps come in handy, but in my experience expose the danger of a board lifting up when using upcut spiral bits to profile cut a part, or rough cutting deep 3D projects. The painter's tape and glue strategy has come in handy on occasion, but being a consumable method I don't use it when other clamping methods will do. I've seen but not tried using a biscuit jointer or domino machine to cut slots in the side of boards for clamps to hook into when you can't put a clamp over the top of the piece.
4D

Reactions: 1

Random_Poster

· #11 · 8 mo ago

4DThinker said:
I've seen but not tried using a biscuit jointer or domino machine to cut slots in the side of boards for clamps to hook into when you can't put a clamp over the top of the piece.

hmmm..... Interesting idea.

4DThinker

· #12 · 8 mo ago

I've also used wedges to clamp parts against a fixed edge. Bolt or clamp one tapered edge half down a short distance from the material being held, then slide a loose tapered board between the fixed half and the material board. Tap in place to lock the material in place. Tap on the other end to free the wedge. The long face of the wedge against the board holds better than the tangent edge of a cam rotating clamp.
4D

Random_Poster

· #13 · 8 mo ago

4DThinker said:
I've also used wedges to clamp parts against a fixed edge. Bolt or clamp one tapered edge half down a short distance from the material being held, then slide a loose tapered board between the fixed half and the material board. Tap in place to lock the material in place. Tap on the other end to free the wedge. The long face of the wedge against the board holds better than the tangent edge of a cam rotating clamp.
4D

Another idea worth trying, thank you. I've had the issue of a work piece lifting a little when using my home made cam clamps; I could never get a tight enough pinch. The wedge sounds like it may "bind" better.
I've been using the tape and glue idea with thin cam clamps when I need the machine to carve the edge of a board. The wedge could be a firmer hold and be a consumable scrap. Thanks

old55

· #14 · 8 mo ago

Welcome to the forum @Random_Poster

jw2170

· #15 · 8 mo ago

Welcome to the forum @asah
I would not like to see that happen......

jw2170

· #16 · 8 mo ago

Belated , welcome to the forum @Random_Poster,

MarkJonesRanger

Discussion Starter · #17 · 8 mo ago

asah said:
newbie question: is this dangerous? my router's bit is not protected behind any kind of shield, so if it breaks wouldn't it go flying (towards me...)? Festool OF 1010

I haven't had a bit go flying yet they mainly just drop on the table top. i have had pieces of projects go flying and embed themselves in my 3/4" foam enclosure box I have over the top of the CNC like a big foam cooler that sits over the top of the 40x 50" table.

Reactions: 1

Jared355

· #18 · 7 mo ago

I’ve learned over the years to really slow the feed down on a trial run and to have one hand on the stop button while testing a new program out and i haven’t hit a clamp in years

Reactions: 1

MarkJonesRanger

Discussion Starter · #19 · 7 mo ago

2 days ago I went through a brass screw while running a quick program to cut out some feather boards out of some pvc that I had already carved up revisions 1 and 2 of a vacuum jig. I am glad it didn't hurt the bit. It just kept cutting right through it. Brass screws while they do strip out have saved my bits several times. When I know the gcode won't cut into the screw i will then use regular screws.

Also noticed the impact drill doesn't strip the brass screws out as fast as a regular drill does.

Reactions: 1

reuelt

· #20 · 6 mo ago (Edited)

I only use M6 Countersunk Nylon screws to hold wood pieces for CNC routing. Sometimes with 1" nylon washers. Easy to cut to length.
Nylon screws screws into M6 T-slot nuts (my CNC routers has ALuminium table with T-slots)
Even if the router bit hits any, it will just cut thru it and X and Y position is NOT even affected.
I drill M6 countersunk holes in larger workpiece or I just use large nylon washers for work piece I can't drill holes. Washer fits into biscuit joiner slots at workpiece sides.
Can have very low safe-Z since coutersunk screw is at Z=0.level.

Lighting Gas Cylinder Font Plastic

Product Rectangle Household hardware Auto part Technology

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