Cut Accurate Size Holes w/ CNC Router, How To CNC Woodworking Tips And Tricks For Beginners v-carve
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- Опубліковано 2 гру 2020
- Getting exact hole sizes in your woodworking projects with a CNC router is a known issue and there is a way to get the holes to the EXACT size.
Making holes the exact size requires a bit of understanding of how the program is set up. This trick will take you to the next level with your CNC router.
The tips in this video show you how the industry compensates for a well-known issue and how to compensate for it.
The reasons hole sizes vary are many..material variations, size of the hole, the machine, cutting tool, etc.
All cnc software has features that allow you to take this into account. It will be called "allowance" or "offset". This will tell the program how to write the code to run holes with your CNC router.
When you enter an offset, you are telling the software to add or remove that amount from the tool diameter
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VECTRIC SOFTWARE LINKS
[Please use these links when you order. It gives me credit. Thank you]
→ Vcarve Pro (Recommended): shrsl.com/36xfh
→ Vcarve Desktop (24x24” size limit): shrsl.com/36xfj
→ Vectric Aspire (3D modeling): shrsl.com/36xfk
→ Cut2D (for the budget-minded): shrsl.com/36xfm
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ROUTER BITS FOR CNC ROUTERS
→ 8-pc carbide CNC router bit set (w/ free vector files) bit.ly/3d1iQnF
→ 1” Surfacing bit required for surfacing your spoil board: bit.ly/2QEYLKz
OTHER THINGS YOU'LL NEED
→ Calipers. For the price, it is a very good set: amzn.to/338MAt3
→ Hearing protection (plugs don't work): amzn.to/2Hs1RgW
Facebook: IDCWoodcraft
Website: www.idcwoodcraft.com
Email: support@idcwoodcraft.com
#cnc4beginners #cncentrepreneurs #idcwoodcraft
#cncroutertipsandtricks #cnc4beginners #vcarve4beginners #cncroutertutorials vcarvetutorials #bobscnc #xcarve
![Down Bits (Down Cut) And CNC Routers [What You Didn't Know] - Garrett Fromme](http://i.ytimg.com/vi/tykj6Nn-ysM/mqdefault.jpg)
Wow this is good for me as CNC rookie.. Thanks Garrett 👍👍
Ridzeki, you are so welcome my friend.
Very helpful! I couldn't understand why the hole/slot in a part was not close to dimension until I watched this.
L Luttrell, glad to hear this one helped you brother!
No problem Garrett, figured it out, trial and error. Thanks for responding.
PaulMarlmountWoodcrafts, so glad to hear this one helped you my friend.
Excellent explanation video. Thank god we have someone like you to help us rookies. Greatly appreciated Garrett.
Jim, thanks! I'm glad I could help!
There are so many things that can affect the sizing of holes on the CNC router. Toolpath selection, tool deflection, material being cut, feed rates, step over etc even the machine itself. I use Fusion 360 and LinuxCNC on my router. In the past I have used a 2D contour toolpath for holes. I’ve since learned that the circular toolpath results in more accurate holes in both size and roundness. A slower finishing feed rate and a spring pass also helps with accuracy. I also have a CNC vertical mill and don’t experience the same issue on that machine. This machine is more rigid and uses a Siemens control and servo motors. Food for thought.
jasonarnold7578, That's great insight! Indeed, the variables you mentioned play a crucial role in hole sizing accuracy on a CNC router. Using circular toolpaths, adjusting feed rates, and adding spring passes can definitely enhance the precision of the holes. It's interesting how the different machines and controls can impact the results as well. Keep experimenting and fine-tuning your processes for optimal outcomes.
Garrett- THANK YOU for these hole Sizing tips! I have been struggling for HOURS on this problem creating a new spoil board! With this this new knowledge of how to 'adjust' routing different size holes you have really helped me sooo much 💥, as usual! thanks for all the tips in your videos.
Hey Mike! You're welcome! I'm glad this helped you make your spoil board! You're one step closer to cutting!
Once again a very clear explanation of the issue and the solution! Thank you!
Thanks Laddy. And by the way, thank you for the check.
@@IDCWoodcraft Glad you got it, was going to ask in a week or so because it hasn't cleared my account.
Superb video, you just saved an awful lot of head scratching and unnecessary tinkering/research! More importantly I now have holes the correct size and I get to keep my sanity!!! Many thanks for taking the time to share your knowledge and wisdom it's seriously appreciated. Couldn't help but subscribe for more....
Loose, welcome aboard! I'm glad to be a part of your cnc journey and hopefully help you keep ahold of your sanity along the way! Happy cutting my friend!
Love your videos! I always learn so much!
Thanks SB. It's fun passing on my knowledge to other CNC'ers like you.
Thanks again Garrett! Great info.
You're welcome Geoffery
Thanks for the info and replying
Hi Robert. Absolutely, my frined. Was this video helpful?
Regarding the .38" hole with the variance of .005, I think you meant the pocket allowance adjustment should have been -.0025 (.005/2), not -.025. Minor division error, but the explanation was great. Thanks for the videos and the great bits you sent this week !
Hey David. I think you're right. I just forgot to say it. Kind of a big miss. Thanks for commenting about it so others would see
Makes complete sense
sfg18b, right on brother, I'm glad it clicked! Happy cutting!
Thanks for the video on making accurate holes. I always enjoy it when I learned something I didn't know. This tip will go down in my notebook.
Hi Roger. Glad it gave you new information. What kind of projects do you do on your cnc?
@@IDCWoodcraft
Hi Garrett,
I'm not that good at woodworking. To be honest, woodpeckers are better woodworkers than I am. I thought if I built a CNC router my woodworking projects would look more professional. Since I always like a good challenge, I designed and built a CNC router. - At least now my projects look more presentable.
Currently I'm interested in carving sundials. I was going to insert a photo here, but UA-cam won't allow it.
I've been retired for ten years now - LOVE IT!
If you're interested, here's a few articles on CNC routers I had published in SERVO and Nuts & Volts magazines:
“Laser Alignment System for your CNC Router” - SERVO magazine, published in Issue 1, 2020, p.61
“CNC Routers: The Z-Axis Zero Setter” - SERVO magazine, published in Issue 4, 2019, p.40
“How to ‘TRAM’ your CNC Router” - SERVO magazine, published in Issue 3, 2019, p.62
“Make a spring loaded Pen Holder for your CNC Router” - SERVO magazine, published Mar/April 2019, p.46
“CNC Routers: Backlash - What is it? How to measure it” - Nuts and Volts magazine, published Mar/April 2019, p.36
“Beginner’s Guide to CNC Routers” - SERVO magazine, published 2/1/2018, p.46
@@rogersecura378 these are great articles! Thank you for sharing. I will include links like this in my website as I could them. You would also be a good one to talk with, especially as my CNC Entrepreneurs facebook group starts moving along (I will give it full attention after the holidays.
The crack about woodpeckers was funny. But I'm glad you outsmarted with technology. Look forward to engaging with you.
@@IDCWoodcraft Garrett,
Thanks for the kind words about my published articles. Please keep pumping out your great videos.
I absolutely will! I love sharing my knowledge to help other become awesome at thier craft.
I think it has to do with compliance. The spring like action of the mechanics under load. With a bigger circular hole the difference is smaller percentage wise compared to smaller holes. The compliance of say 0.05mm is the same for both holes, but is relatively big for a small hole.
You can compensate in cam by using a negative offset as said in the video, or you can change the backlash setting to compensate automatically.
The problem with both is that under different loads the compliance changes too. More advanced cam software can setup tool paths with a constant load so that the backlash setting is correct in more cases.
More often than not, using a light finishing pass often helps getting closer to the intended diameter. So a contour operation after a pocket operation can help. And you can add some more geometry with an offset for the contour operation if it's still not enough. If it's really critical I usually create a pocket operation and a few contours with different offsets to sneak up to the intended dimension.
There are other factors that have an influence on the dimension: spindle, collet and endmill runout. The higher the runout the bigger the hole. Circles are typically created as line segments which usually are inside the circle you're cutting, so most of it will be under sized depending on the segment resolution.
Measuring errors can also play a part. Measuring smaller holes with calipers gives a smaller indication of a hole than the actual diameter. Using hole gauges is the way to go.
Hi Josh. I like you. You like to take things down to the science just like I do. For those techies out there that really want the meat of machining, read Josh's post!!!!
Great video, I had same problem when I did my 1st finger joints on the CNC, I had to add negative offsite to make my joints fit, not to mention a whole lesson on dog bones. I'm having a great time learning to use my CNC and software. I like you videos keep up the good work.
David, those finger joints can be a pain! I'm so glad to help and to be a part of your CNC journey. Keep up the good work too!
@@IDCWoodcraft Got my 1/8 bit today, My wife loved the note on the package. working on my 1st cribbage board design now. have a great week
@@davidfoster6433 thanks for letting me know you received it.
I am amazed that a 3.750 diameter hole is .050 undersize. The most likely cause is that the feed rate was too fast . I have had my CNC router for over three years and after attending some CNC group meetings, it is so obvious that most people have their feed rates way too high to get the results they want. Most CNC routers that I have seen are not very rigid and the cutter will push away from the workpiece because of this. So if you want to machine a hole that is accurate, you need to slow down the feed rate on the finishing operation.
To machine a pocket that is 3.750 diameter, I would first use the pocket tool path and keep the feed rate on the high side so that it does not take a lot of time to do the bottom surface of the pocket and also set it up to take a finish pass of about .010 off the sidewall f the pocket. Since the bottom is already finished and the diameter is close to size, I would then use the profile tool path (with a slow feed rate) and also set it up to take a finish cut (on the sidewall) of about .002 and you should be able to get within a few thousandths of the size you want.
A while back I made a fixture where I had to fit a 2" diameter pvc pipe in a 1/2 thick piece of maple. and I only had to make a .003 adjustment to get the pipe to fit.
I hope this helps someone to get accurate dimensions on their projects.
Thanks Mark, for the tips you provide here. Yes, one can get very close for sure with finish cuts.
Great job. I am drilling out my dogs on my waste board and this came in very handy!!
Hi Todd. this is definitely a cool technique! I'm glad you were able to put it to use so quick. the best way to retain the info for sure.
What size were your dog holes ?
I’m just about your embark on making a spoil board with 19mm dog holes.
@@PaulMarlmountWoodcrafts I made them all 3/4". Seems most tools and dogs are 3/4"
@@rufustoad1 thank you, appreciated. Can you recall what pocket allowance you had to make for 3/4 in 19mm ?
I just found your channel and subbed. I like the way you explain things, simply and to the point. This is a great explainantion and easy to understand. With those tolerances, a dull bit and heat could be factors too right? Does the big hole start at the outside and work it's way in to center? I'm thinking the most accurate work with the coolest tool. I'm new and transitioning from 3d printing. I'm starting with a cheap 3018, until I get the Programming nailed down.
xj35s, welcome to the channel brother! When it comes to the path your CNC takes, it often depends on the strategy you've set in your CAM (Computer-Aided Manufacturing) software. For example, when cutting out a big hole, you can set the toolpath to start from the outside and spiral in towards the center, or you can have it plunge in the center and work its way out in circles. Each approach has its pros and cons and can be selected based on the desired finish, the material you're cutting, and how much heat you expect to generate.
the first thing you should try when you facing such problem is to run circle code second time. it called "spring pass". just to clear any material left from first pass because of tool deflection.
it's easy.
Hi Vas. I'm not sure why I didn't mention that in this video. It's a gimme in machining. Thanks for commenting. Please always add your thoughts, as I sometimes miss alternatives like what you shared here.
Thanks Garrett! This worked for me.
I was actually using a profile toolpath for the holes to get the 'spiral' ability you discussed in a previous video. I switched it to pocket and conventional path; that got me very close... then I did a .002 offset and it was spot on. You stated in the video "he has to use a pocketing toolpath"... why is that? what is the difference between a pocketing and a profile when you can set the depth and 'on/outside/inside' the line?
I have the KL744.
Thanks again for sharing your knowledge.
Ah, Jim...you're challenging me to make another video. Good. I will do that. To answer your question here, a pocket tool path creates a pocket (removes all material from the center to the selected boundary) Profile tool path only follows a line (or boundary) For the large circle, if you used a pocket, it will cut all the materil from center. If you used a profile, it will cut on / inside / outside the line and leave a plug.
I'm glad you were able to get exact holes. Glad I can help.
@@IDCWoodcraft but you can set the depth of the cut on a profile path. If I set my depth of .2" and use an 'inside' toolpath, how would that differ from a pocket toolpath of .2" on a small hole (where the bit is large enough to clear out all the waste)?
Using the conventional toolpath and a pocket, it did make a difference in the cut; just not sure I understand why.
@@jimaikman2875 profile works EXACTLY the same except it does not clear out all material, just along the line (inside/on/outside). I'm guessing you used a profile (which I should have edited that part out because you can do both). what I instructed in this video works the same with profile. You did it just fine.
I should have included both tool paths in the video. That would have added a lot more to the video. My apologies for confusing you. I will make another video about profile toolpaths and the same technique.
Hi Garrett, just discovered your channel the other day and find it very helpful. I’m sure your subscribership will be growing. I watched this video on sizing holes, and also your video on drilling holes. Both very informative and I learned several things from each. In one of them you mentioned giving you ideas for new videos, so I thought I would suggest “making round circles”. In one of the videos you also mentioned hole making is notoriously difficult (my interpretation of your words) in the CNC world. I have a large home brewed machine that makes perfect squares, but most circles are ovals or look like Mickey Mouse’s head (heck, or Goofy’s head depending). Worked with a variety of folks on a variety of topics from backlash to vector creation. Perhaps you could do a video on the settings you use (feed rates, acceleration, etc) to maximize the accuracy of your circles? That would be awesome
Hi CNC. I will work on this with other experts, since I am not a froubleshooter. However, Jeff Holmes is. Watch this video and make contact with this guy. He is really good at this stuff ua-cam.com/video/nCFaxKxomC8/v-deo.html
yes, I see ovals would be more of a problem than "round" holes because of the grain
simple way ofdescribing the "climb cut" is back peddaling the bitas some people will go with the rotation instead of normal against it so as to have no tear out.
I never heard of 'back-pedaling' term used before. I might start to use it
To use this method you'll have to cut test holes of the various size holes in the same type of material in order to measure the error. If you're already cutting test holes, I would try conventional cut as well to see if that would correct it.
David, very good point brother. Wood is a bit tricky and just like you said, to get good accurate holes you need to run some tests too!
Since both holes were cut with 1/4EM even though different toolpaths, can you still group the 1/4EM together?
Good video and the explanation helped quite a few areas
Hi Choate. I can combine toolpaths only if the offset value is the same for both size holes.
Great information, If my endmill is slightly under sized should I make the tool data base reflect that measurement or use the tool off set feature?
Thank you for you time!
Hi Kevin. The tool database has no impact or relationship to the machine size
It seems to me you should enter the actual size of the bit in your tool database, but you may still have to go through the procedure discussed to get an accurate hole size.
The reason that the difference in tolerance is 10x more between the . 3.7 hole vs the .38 one is because the 3.7 hole is 9.74 bigger than the .38 hole. The difference in the hole size you want to be and what you actually get are .9864% for the 3.7 hole and .9868%. For the ..38 one. Take in the error factor of measurement, both holes are of by .986% off. So I you could just be able to put in a percentage change for the Pocket Allowance, both holes would come out perfect. Or any other hole size you choose to use.
I’ve been trying to figure out why my holes are always a bit off and this video seems to be on the right path.
Mark, do you know if post machines have a standard error of some kind like this?
@@JohnGrubb1
John Grubb, I been been retired for awhile from using a CNC machine for awhile. But have one coming to me in July. I am now learning Vcarve ( was learning MARCH3) so I to am just learning the new ways of doing woodworking with such software. And post machines
I would like too try a slower speed rate and steep over for just holes to see if you could achieve better tolerances for holes. I do not now if the software does this already for you. Kind of like jerk ( if I remember right that is what slows down the travel speed rate as it transverse around a corner)
Hi Mark. It's always a bit of playing around until you get it. Thanks for taking this so deep. I always emjoy some good number crunching.
Howdy Wayne here, my question is why pocket not profile to cut holes?
Wayne, you will be left with material in the middle! Profile will work well on smaller holes too.
Thanks for the vid Garrett, I was doing hinge holes for my kitchen cupboard which was something similar, one 35 and two 8mm holes, when I came to insert them they would not fit , I have adjusted the toolpath as you suggested .2mm in my case and will give it a go tomorrow. On another thought does this have to be done to each hole in future? Chee
BungalowBill58, you are so welcome my friend. As for your question, yes you will need to do this to every hole.
@idcwoodcraft. Garret, great video as I had the same problem recently and was looking for a solution. I have a newbie question. How do you accurately measure these circle diameters after cutting? I would think a pair of calipers would work, but going to level of thousands seems to be difficult. If calipers were used how do you know the exact geometric chord is precisely going through the center of the circle? Thanks in advance! And love your bits, I have several along with the Sienci MKII.
Headdancer1, Hey there! Glad you found the video helpful. When measuring circle diameters after cutting, you can use digital calipers for accuracy. To find the center of the circle, measure the diameter at various points and find the average. Using calipers ensures precise measurements for woodworking projects. Keep enjoying your bits and Sienci MKII! Here is a link to calipers I recommend: idcwoodcraft.com/products/calipers-digital
HI Garrett i am currently using vcarve pro trial version 11 and there are many thing different in the toolpath section it seam to be missing a lot of the steps that you describe in this video. i just tried to cut out a 1.30 size hole using a pocket toolpath and it only cut the perimeter of the circle in the tool path preview
You are using a profile toolpath which is right. You will need to pocket out the hole first using the pocketing. If you are missing features I am using, click 'view advanced toolpaths' in the topp of the particular toolpath. It will show up
So you need to cut a test hole at your desired diameter first, so you can see what the deviation is, correct? Does this deviation change as the bit heats up? One more question: I assume the deviation is less if you use a larger shank bit? I’m looking at making an MFT style table top when I get my CNC and I have been wondering about how to get the holes accurate. Thanks for the video!
michaelbeckwith977, Yes, cutting a test hole is a good practice to check for deviations. The deviation may increase slightly as the bit heats up during prolonged use. Typically, using a larger shank bit can help reduce deviations since it offers more stability during operation. Good luck on your MFT style table top project, and you're welcome!
Why pocket if a contour cut(smaller than the original hole dia but right through the material) with a pocket cut as a finish op would be a faster option?
Pocket is not always necessary. If I could do this video over again, I’d do it a bit differently. However, the principle is clear…how to get the right size holes
Back in the day in my manufacturing days we lied to machine saying we used example .240 size tool. Is the a thing with these type cnc machines
craig12272, I understand that in some manufacturing settings, people may input inaccurate tool sizes to achieve certain results, but it's not recommended practice. CNC machines rely on accurate tool data for precise cuts and to prevent damage to the machine or workpiece. It's best to use correct tool sizes to ensure optimal performance and quality results brother!
Thanks Todd. Can you recall what pocket allowance you had to make ?
Paul, sorry brother it's been so long that I don't quite remember on this one!
So how do we know what our tool allowance is if we're working with a one off part? Or material? I cant cut a test hole into this to calculate allowances. Thank you.
the hole will almost always cut undersize when you tell it to cut with no offset. Let that cut, measure, then set the toolpath with the offset and run only that path. Does that help
It seems like this is treating the symptom instead of the cause...and you would have to have already run it to know how much you were off and then adjust? Wouldn't a finishing tool path come out close to dead on because you've eliminated the cutter deflection by taking a tiny amount of material off? Also not sure why that big hole would be cut with a pocket tool path instead of a profile tool path, why clear the whole thing unless that was a partial depth pocket and not a hole? These are questions from someone on the steep initial part of the learning curve so no offense meant if the answers are simple. I'm laying out a whole new spoil board with dog holes right now and it will be important to get the hole sizes right.. 👍
Hi DSD. there are several ways to think about this. Remember, this is for beginners...well, in this case, intermediate. sometimes it has to do with more than deflection. The machine just mat not be rigid enough, so it 'deflects' the machine more so than the tool.
Is anyone interested in buying a self squaring add-on for machines that use dm542t stepper drivers?
Maker, very cool brother. That is a very interesting idea.
@@IDCWoodcraft i actually make it work on my cnc router
The variance seemed to be directly proportional to the hole size.
I tend to think it might be machine calibration as in steps per mm
Hi Mark It would be nice if it were that simple. It's not. That's why industrial machines have cutter compensation.
@@IDCWoodcraft I am sorry I disagree. Cutter compensation is for bit variance or bit deflection.
Bit deflection does not get multiplied based on the size of the pocket or diameter of the circle being cut.
@@markbachman8321 there are several ways to look at it. You clearly have some machining experience. And you are correct, step resolution does have a big impact.
My dad worked in a fab shop that dealt
My dad dealt with +-.002 on stainless steel. In his Era, scratch awl and center punch were the tools. Wow. What precision.
Ron, times sure have changed!
A person almost needs a chart so that you don’t have to keep doing test holes to figure out the variance constantly.
Hey Sim. I would agree. This is a more advanced type of issue to solve.
Why would you pocket something you are cutting all the way through? Just us a 1/8 inch profile cut and cut it out in a few passes right ?
You bring up a good point. This example is not a thru hole. I'll update my description. Thank you.
Regardles, precise holes (in V-carve at least can only be done with pocking, not profile.
With smaller diameter holes I have found that pockets for holes are often easier than profiles because because I don't need to be concerned about using tabs or another method to secure the resulting loose waste material. They take longer but the chance of a loose waste part moving into the path of the moving bit is eliminated.
The only thing that doesn't make sense to me is using a negative number to make a larger hole lol
SL, its all about what it is in relation to brother! Try it a few times on your own and it will start to make sense!
When I cut squares they are perfect, but when I cut circles the cut more like ellipses. How do I fix this this? Thank you.
This has to do with stepper translation as it is coordinating the 2 motors. It depends on your controller software.. What do you use?
@@IDCWoodcraft I use Mach 3 with a Pokey57CNC motion controller. Thanks for any assistance you can provide.
@@rickmccaskill7888 I don't use either. I'm afraid I cannot help through this means of communication. We can hop on the phone and work through it. You can schedule time with me through my website www.idcwoodcraft.com
My cnc machine has the same problem.
Mach3 with an usb controller.
@@alejandroperez5368 I'm afraid I cannot help with this issue at the moment. I can tell you it is a speed ratio relationship that is set in your control software. In othdr words, the rate of speed signals being sent to the x stepper are different than the ones being sent to the y stepper. It is a simple number change.
Wow, very interesting, so much to learn. Thank you. It would have been neat to see the before and after with some real wood. One suggestion on the video, try not to zoom in and out and move the screen around quickly, it’s a little disorienting, specifically starting at 3:50. Otherwise, good video, good content and thoughtful explanation.
Thanks JC. I was thinking to reshoot the video but I'll let it ride for a bit. I still have to do 2 important videos...climb versus conventional milling, eliminating witness marks and a couple others.
@@IDCWoodcraft Agreed, I wouldn't reshoot it, more content is always better to help grow the channel. Just a tip for the future. Keep up the good work!
@@JC-nu6mn Thanks Brother
The reason I didn't do demonstration was because I am working on some jobs (getting busy) and it takes a long time to prep for videos (notes, organizing, machine setups, filming, refilming, editing, uploading, writing descriptions, setting up taga to gete the UA-cam algorythms to push it up toward top of searches, on and on) This video to 3 hours to prep for. Just so you know...some of those 10 minute videos take 8 hours to put together complete.
Of course, I love sharingmy knowledge with people like you so am very happy to do it to the best of my ability
@@IDCWoodcraft No worries Garrett. It's obvious from your videos you put a lot of time in to them. I enjoy watching them. Just offering some suggestions as your channel continues to grow. Congrats on 100 subscribers btw!
This is university for CNC routing.
Scott, you crack me up, lol. But a hell of a compliment.
That actualy look like bad steps/mm
Ten Times larger hole has ten times more material left
Good point Fix