Designing T Slots and Dovetails for Machinabilty
HTML-код
- Опубликовано: 17 сен 2024
- Looking at design considerations for using undercut tooling like dovetail cutters and woodruff mills. Getting the part design to work with existing tooling will get you the best price on your machined parts.
I’ve really been enjoying this series on designing for manufacturability. Thanks for dropping the knowledge.
Me too 🙂
Me too too. But I doubt a 20yo lady needs to know it. But I do. And I that's fun
I struggle with when to explicitly model fillets, chamfers, and reliefs when it's not a required functional feature but some solution is required for manufacturing. If I model them, they appear in the step file as a fixed-size/shape feature that could be seen as a requirement rather than an allowance. If I just do a drawing note on a sharp edge (e.g. R .03 MAX), it's not necessarily associative back to the model and changes to the model.
Im not an engineer, designer or machinist. Im a geologist. Regardless I love watching videos about all these little details that go into the things we take for granted. So thanks for sharing!
I always think I’m pretty in tune with my inner machinist but that drop hole dovetail method is something so elegant that I’ve never thought of before.
This whole series has been so great! Thanks for the ever-increasing production value
For what it’s worth, there’s a “Parker O-Ring Manual”, ORD 5700, can be found online, that makes a excellent reference for o-rings and o-ring gland dimensions…
Yep. Use those tables every day at work. lol
I have no use for this information, but I still like watching these videos.
Thank you Adam...these are all golden. I will be sharing these with the engineers I work with. Best very detailed examples that I have seen...I work with so many engineers that don't realize what it takes to really make those tiny tolerances they put on drawings that they don't usually understand and 90% of the time don't need. thank you again!
stellar information. Rare to find things that take a lifetime to learn and get good at for free on the internet.
Legit dropping a wealth of knowledge in less than 20 min.
Thank you so much for continuing this series!
The production quality of your videos is improving constantly. And the clarity of the narration plus visuals really helps to understand each topic.
So, thank you for taking the time to pass on your knowledge. 👍🇳🇱
😊 Thankyou so much for sharing this series on manufacturinability.
As a person learning this is priceless information.
Thanks Adam! AB tools oring cutters for grooves w/out drop hole saved me a couple weeks back when Harvey's solution just would not survive. Great content! Looking forwards to the next Precision Microcast too!
I am lucky to have a great teacher. Thank you for your work.
thanks for picking up the undercut topic.
O-Ring grooves are always special. i once had to design a groove around a non-circular insert close to a relative high wall that the customer could hardly manufacture (but they requested it).
these days, i would ask them, to look for someone who has a machine like the Hermle C32, which can run a kind of scraping tool along a path to cut a clean groove... would also give a better sealing surface then a high-speed-3mm endmill on a 50mm extension or so :D
Once again, a very comprehensive and informative video. Thank you for putting these together!
Would you consider making one about grinding basics as well? It is pretty hard to find good information (meaning true and unbiased real-world knowledge) about things like tool selection, order of operations, different stock removal strategies and so on, as well as tips to achieve a given finish and tolerance and sorting out common problems. That would also be really helpful.
i love the use of combined vertical and square video!
Hey Adam, I really enjoy this format. It brings a lot of value to engineers and machinists alike!
About those full dovetail O-ring grooves- I always mill them with a ball endmill in a 5 axis simultaneous contour. It's a very simple, reliable toolpath and the tool diameter doesn't get too crazy small. The biggest challenge is blending the tools from grooving and from picking out the corners.
Maybe something to consider if a shop has 5 axis capacity.
Thank you for these videos! As a mechanical engineer and a machinist they help me immensely!
I see some of those strange features being more of a 5 axis job, or done as a shaping operation, too. Keep the videos coming.
Last year we had to make a quote for a part that would require a T-slot cutter with a cutting diameter of Ø25mm... and a shank of Ø2mm. In stainless steel. The T-slot was 40mm down in a hole - so yeah. We literally had to cut the step file of the part in half and draw a tool, then simulate and figure out if it would ever be possible. Ø25xØ2 was the only dimension possible for that feature to be made.
We ended up calling the customer and telling them it would be too hard for us to do.
"Oh that feature? It actually isnt really needed"
🙃
Sounds about right
You are the best machining resource. Keep it up.
I love all your design vids you have been sharing, as a newbie it is great :)
Im in electrical engineering, so i will probably never use this knowledge, but thank you for it anyway. This is very interesting
I’m Learning A Lot About Tools Though Your Series. Thanks
Adam, I truly appreciate your efforts in these videos. This is stuff that is just off the cuff for you, but is absolutely invaluable information to people beginning to design parts.
There is a huge gap between making something in CAD and having a part design in a way that can be scaled. You're helping bridge the gap, and I really appreciate it.
Please continue this DFM video series.
I'd love to see a video on dos and don'ts when designing parts for lathes.
Also a video on which type of tools are "comfortable" in which tolerance ranges. IE lathes might more easily hold a tighter tolerance then a mill for example.
Thanks mate!
Definitely a great series. But at some point I need you to talk about long overhang necked down tooling. I can choke up on the end mill, play with the RPM/feed, DOC, RDOC on a 10xD Harvey end mill in aluminum and it'll still chatter. No idea how some guys use these on anything harder. Everywhere from just under Harvey's recommendations to well under. 8xD or lower is smooth sailing but once we get to like 10xD I gotta turn the RPM down to like 500...
great video Adam.
great video, really appreciate you sharing the knowledge with us.
I’ve been sharing every episode with co workers. So much free information 🤘
Thanks for the videos. I always pick up something new when watching them.
For dovetail drop holes, it's important to put the drop hole on the side with the higher pressure so the pressure delta pushes the o-ring into the continuous dovetail side.
Thanks for the content, you have found a gap in the RUclips content that really needs addressing. You rightly shift the emphasis from MMR to the fundamentals of design to make efficient products.
I would like to add that extension rods can easily be made to lengthen piloted counterbores and work really well in a drill press and sometimes in a pistol drill.
Very educational! Thank you!
very good video Adam,,thanks for your time
I'm reverse-engineering a handguard right now so to say this is priceless universal timing would practically be an understatement. Thank you again sir. Any chance you're working on a video about machining considerations when designing aluminum extrusion dies?
Thanks for these videos, lots of useful information in here.
Fantastic. Thanks again!
Great stuff. Thank you!
Another great video.
Another really good video as usual!
Thank you for your time and expertise. Cheers.
This awesome info should be a subset of AutoCad tutorials for people actually training to design stuff. WOW!
Thanks for the awesome videos
We had some parts with a 3/8 wide * 3/16 tall t-slot with a 3/16 slot and couldn't find anyone making an off the shelf tool to do it, wound up just grinding a 3/8 3 flute endmill and it worked surprisingly well finish-wise but chip removal was a problem. We wound up grinding up a 5/16 one to rough it out and that ended up being a good solution. Granted this was all low tolerance work in aluminum, but it still made the parts substantially more expensive. Unnerving to run is a perfect way to put it, if the air blast wasn't in the exact right place it would weld up in half a second
Instead of having a small o-ring grove with a dovetail you can make the mating part the outside diameter of the gland.
For multiple o-rings position will need to be considered but this allows for a dovetail feature to retain the o-ring without the machining drawbacks.
That’s slick
Amazing video! Thank you!
I did not expect to hear Trepaning tool.
Back facing even seems like something that you might even look at manual machining options if it's a small enough production run (say it's a one-off or you're still prototyping and working on a way to not have that feature needed, but you need to get it made at the state it's in now)
Gold is raining from RUclips, Collect as much as possible.
I think you could make a blind T slot without an entry hole, with enough time & money. Mill the slot center, then go in with a set of successively larger-overhang boring bars to mill the undercut. As long as you feed it in aligned such that it clears the slot walls before starting the spindle, and there's a small enough depth of cut that it doesn't instantly shatter or stall the machine with the startup torque, you can do it. With great difficulty and expense, but it should be possible as long as the undercut isn't too big.
for the O-ring groove, could you not make a half dovetail trepanning tool and swirl down with an eccentric motion?
The main issue with most chip related troubles is the lack of proper chip evacuation... I prefer straight mineral oil as a coolant, as it does not ruin machines, on the contrary, it absolutely prevents rust and lubricates the tooling, improving the surface finish and tool life, while offsetting the lack of cooling capacity that oil has with the reduced friction of the tool and thus lesser heat generation in the first place...
The point that i`m trying to get to is that if you have a good cooling system, or rather - washing system, that is set up in such a manner that if follows the tool and blasts the chips out of the flutes, you have effectively removed 90% of chip buildup troubles... A nice blast of constant high pressure oil from a precise nozzle, aimed at the flutes will do wonders, even in dovetails and T-slots...
The main issue that people have is shitty setup of the coolant nozzles and sloth regarding actually bothering to set the nozzles up for each cutter or even a specific cut in a part... Just having a cnc style multi nozzle, high pressure blasting coolant ain`t enough if those nozzles are aiming at shit... Quite like coolant on a surface grinder... There are so many ways in which your coolant can be nearly useless on a surface grinder, regardless of it`s flow rate or pressure...
Coolant is literally a tool in it`s own right, almost like those olden machine accessory drill guides that bolted onto a machine and lead a drill precisely where it had to go(speaking of olden jig borers for the most part); you can`t just have an accessory bolted onto a machine and demand of it to do miracles if you are the one fucking up and setting it up poorly...
One to three nozzles are what you need... Get some nice inox seamless pipe, some 4mm i.d. or 160thou for you pondscum suckers(across the pond reference)... Make a nice articulating arm that will carry those, or rather - carry the carrier that will carry those... Make it so that you can easily set them up and move each pipe or just the one into any position... Bend the pipe in a Z of sorts, you know what i mean, not Z but more of a one leg of a swastika, no pun intended - so that the pipe can be swung right against the shank(parallel to) of a cutter and aimed at the flutes or teeth or whatever cutter uses as cutting edges... Fuck the flex-pipe, get some hard pipe and make something that does a job well!
Coolant can just be pissed on a part and hopefully on the tool, and sure, it will do something, but that`s like tossing some crap in the pot, adding salt and hoping the stove will work wonders from your lack of effort... If you want it to do it`s job to full potential, you have to set up every aspect of it properly and approach the situation accordingly...
Roughing cuts need all the attention and help as it aids the tool and reduces the stress imparted on the material if the cutter is allowed to just shave the chips off rather than battling it`s way through a slab... Finishing passes on the other hand need all the attention and help to maximize the surface finish grade and again aid the tool itself... The better the lubrication and washing away of chips - the better the edge retention and thereby the nicer the surface finish it imparts and the longer it will be able to do so!
The surface finish of the edge itself is actually what generates the surface finish in the material... Try mirror lapping a lathe cutter and try an identical cutter with just a honed surface at identical speeds and feeds as a finishing cutter...
Also, here`s a free tip for those of you who read this crap - get some used masonry SDS drills with carbide tips, the large ones, get them second hand(expensive af when new and good quality) - extract that nice chunk of large carbide and braze it to a slab o` steel that fits your lathe toolpost(maybe even cut it in two with a diamond zipdisc, they are large)... Braze that shit well and put a good geometry+mirror finish to it and behold the best cutter you will ever have used... Those carbides are not your typical machine carbide - those eat impacts and all sorts of abuse like it`s nothing, just give them constant flood cooling as they again - are not typical machine grade carbide...
But yeah, i`ll cut the rant here... Treat your coolant pipe like your piss hose - always aim before blasting away...
Best regards!
Steuss
Thanks Adam. Once again I feel like Neo plugging in to the Matrix with these videos. I know Kung Fu (okay, how to design less janky and more manufacturable parts).
Id been asking myself what those corner rounding ball mills were for and now I have an answer!
98% of these problems would go away if the designers were made to manufacture their own designs 😉
8:30
I'm sure it doesn't exist, but I wonder if you could use a single flute dovetail cutter that's decently wide and use an oriented spindle to drop down into the slot, then run and cut your dove tail, and then orient out
👍👍
It would be nice if there was a dove tail standard for common sizes and cross section geometry.
There is: the Parker O-ring handbook.
Great video, but I was left on the edge of my seat regarding that blind T slot. I was hoping you would describe how it *could* be done. Is there any way to machine it or is it a complete no-go?
Now you've made me curious about high efficiency milling with a t-slot cutter, sure the shaft is thinner but tooth load should be maybe a third?
When you have a t-slot or dovetail that runs the full width of the part, when are shaping operations a viable alternative to milling?
Hey Adam, I recently came across a drawing at work that had a round undercut shape. Imagine an upside down lightbulb. They did it to slide a 1 in dia. Rubber tube into the part but I didnt know how they got it machined. Any thoughts? It had about .75 in neck and 1 in circular undercut.
I’m seriously considering making these videos a part of onboarding for new engineers. Would rather get them young than after they’ve decided design should dictate manufacturing 🤢
11:39 which tool is that? i am looking for a tool that i can use to slit up to tool steel (to cut off small parts) something like 20mm side cutting and 1mm thick.
whats the best way to modify it to serve as a t-nut and especially in terms of budget and simplicity? I have modified roof racks which I painstakingly modified the square under the head with a dremel. However the carriage bolts work well and are cheap but more precision would be nice.
14:50 On the blind T slot example, couldn't you go in with an eccentric cutter that is essentially a boring bar? That would allow you to use a larger neck for a given undercut width compared to using a T slot cutter. (Not trying to defend the part designer, I promise!)
What's your take on dovetails using a shaper? (linear motion tool instead of rotary)
Is it possible to have a hybrid dovetail trepan tool? Something 3 or 4 flute with a lot of meat behind each cutting edge to handle the plunge load and with a little relief to accommodate a small circular interpolation?
Do u use any form tools? (Milling form tools?) so features a 16:02 ish sinker edm?
wire edm go brrrrrttttttttt
First few minutes of the video --- set the block on its side and just wire edm them all. Way easier, and a lot less nerve wracking (and would be more accurate). 🙂
Another operation is more costly
Try to avoid designs that require these tools, usually the part is poorly designed and needs iteration
*Designing T-Slots and Dovetails for Machinability: Key Takeaways*
* *0:00** Undercut Tooling Design Considerations:* When designing parts with features that require undercut tooling (dovetail cutters, Woodruff keyseat cutters, T-slot cutters, etc.), consider the distance from the cutting edge to the tool's "neck" (the thinnest part of the tool's shank). A narrow neck limits tool options and can make machining difficult and unreliable.
* *1:11** Dovetail Cutters:*
* 60-degree dovetails are generally easy to machine with standard tooling.
* Sharper angles (e.g., 45-degrees) require wider or shallower dovetails to accommodate the cutter's neck.
* Fully tangent corner radii often require more expensive ball end mills. Consider if a non-tangent radius is acceptable.
* *5:00** Dovetail O-Ring Grooves:*
* Dovetail o-ring grooves can be challenging to machine, especially with small o-ring sections, due to the fragility of the cutters.
* Consider alternatives like drop holes or half dovetails, which allow for the use of larger, more robust cutters.
* Standard o-ring grooves (straight walls) machined with trepanning tools are the fastest and often provide better sealing due to the orientation of the machining marks.
* *9:54** Side Milling and T-Slot Cutters:*
* Side milling cutters are designed primarily for cutting from the side and have limited bottom cutting capabilities.
* T-slot cutters can cut from the side and bottom. However, they require a full-width cut (no roughing passes), making chip evacuation and tool deflection critical considerations.
* *13:15** T-Slot Design Limitations:*
* Limit the "step over" (distance from the cutting edge to the side of the slot) to no more than 1/3 of the cutter diameter for reliable machining.
* Avoid blind T-slots if possible, as they severely restrict tool choices. Consider drop holes as an alternative.
* *16:25** Spot Facing and Back Facing Tools:*
* When spot facing is required in difficult-to-access areas, back facing tools may be necessary. These tools deploy a cutter after entering a hole, allowing for machining on the back side of a part.
* *18:31** General Recommendations:*
* Consult tool manufacturer catalogs (e.g., Harvey Tools, Iscar) to understand the capabilities and limitations of available tooling *before* finalizing your design.
* Designing features that work with readily available tooling will lead to lower manufacturing costs and better part quality.
I used gemini-1.5-pro-exp-0801 on rocketrecap dot com to summarize the transcript.
Cost (if I didn't use the free tier): $0.07
Input tokens: 18189
Output tokens: 582
The internet is dead
Adam I have some inquireries about a part and would like your insight. How can I get a hold of you?