Correcting the DIY dovetail cutter geometry || RotarySMP

Sometimes, things go go according to plan. You just have to work through the challenges as they appear and keep on.
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Last week I interviewed CNC Shop owner of Høj Maskinteknik, #nikolaiownz
Here is a link to the interview:
kzbin.infoyoel95vq1TU
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00:00 - Intro
00:39 - Challenge #1: Slotting tool path from Freecad
02:28 - Challenge #2: Dialing in the dovetail cutter
04:08 - Challenge #3: Getting the work held flat.
06:17 - DIY Dovetail cutter wrong geometry
07:47 - Mailtime
10:01 - Challenge #4: Fixing the DIY dovetail cutter geometry
11:50 - Challenge #5: Mill eletrical problems.
15:53 - Challenge #6 - Correct dovetail depth

[@WillemvanLonden]

So that means we're not engaged?

[@RotarySMP]

Hi Willem, nah I had to break it off :) Thanks a lot for the clamp pair. What 3D printer are you using?

[@WillemvanLonden]

@@RotarySMP Bambu Lab P1p Had a Qidi Tech first (Clough42 gave a possitive review) but I had to send it back, because it didn't work. Wouldn't even load a software update. The Bambu Lab is great. I van recommend it.

[@tobiasripper4124]

uuhh you got frienzoned hard budy.. not that i'd know what thats like. that never happend nor will ever happen to me again.

[@ptonpc]

You should at least be going steady :D

[@TheDistur]

Poor Willem.

[@iolithblue]

Never machined a thing in my life, dont expect to. Love the channel, love the honesty and the perfectly imperfect nature of it all. Keep it up big fella.

[@RotarySMP]

Thanks 👍

[@EdgePrecision]

On some inexpensive vises (cheap) the frame of the vise is not the best cast iron. So when you tighten them it flexes the whole body of the vise. That is what’s causing you problem with the vise. You can test this by putting you indicator on the moving jaw side of your part or on the vise itself. With the part just snug but not tight in the vise. Then tighten the vise. You will see the movement. If you must use the vise whet you can do is tighten it to make your roughing cuts. Then losen and just tighten it lightly just enough to hold the part for the finish cuts. You may need to program with this in mind separating your finish cuts. Another thing that can help is to put more clamps on the base of the vise trying to use the table to increase the vises strength.

[@RotarySMP]

Thanks for your tips Peter. I really need to save up for a decent vise though :)

[@dobsonmartin]

I love that everything isn't perfect on the first pass. Shows the process that you go through. Very good videos!

[@RotarySMP]

Thanks for your kind feedback Martin.

[@ptonpc]

That clamp is even better than an engagement ring!

[@RotarySMP]

Sure is:)

[@philip_fletcher]

Just a heads up: FreeCAD's 'Path' workbench has been renamed to 'CAM' in dev (and therefore the next release). I think it has also gotten a bit of love.

[@RotarySMP]

Thank Phillip. I am slowly getting better with it.

[@GeoffTV2]

Thank you for the video, nice fix up on the dovetail cutter. Also, any woman that forbids lawn mowing sounds like a keeper - Heather

[@RotarySMP]

She liked your comment ;)

[@GeoffTV2]

@@RotarySMP 😆

[@trollforge]

Time to plant Crocuses, Daffodils, and Hyacinths... should give no mowing from Snow melt to the end of July...

[@GeoffTV2]

@@trollforge👍 Flawless logic right there

[@jasonhull5712]

It’s not magic, it’s just common sense and practical machining techniques that achieve the desired results. Always enjoy your content my friend. Very well executed. Loved it !

[@RotarySMP]

Thanks for your support Jason.

[@cooperised]

Woohoo, my comment got featured! I feel special. Also, nice work on the fix.

[@RotarySMP]

Thanks for your input. It was good to fix that.

[@TheChillieboo]

first time watch your channel and DAMN!, of all the impressive things, im most impressed that youre effectively utilizing freecad!

[@RotarySMP]

Thanks for your kind feedback. It took a bit of practice to learn Freecad, but there are very good tutorials which help.

[@kenthesparky178]

It could have been worse, two steps forward and three back.😂 Another entertaining video.👍

[@RotarySMP]

Glad you enjoyed it Ken. Thanks for the feedback.

[@jimsvideos7201]

Thank you for the geometry, I'd have done the same thing you did.

[@RotarySMP]

Thanks Jim.

[@superdfs]

It’s like Korg doing CNC great vids! 👍🏻

[@RotarySMP]

Glad you like them!

[@TheDistur]

Good job getting everything corrected and dialed in. 🎉

[@RotarySMP]

Thanks. I am not used to doing series production (even if this is just 12), and Luke put a lot of work into these blanks, so I dont want to scrap any.

[@RickRolling-tc7vb]

Good stuff, that was great fun. This is like Bear Grils, but in a home machine shop. So many adventures in one video! Next week, see Mark drink his own coolant to survive.

[@RotarySMP]

Thanks for the kind feedback Rick. That coolant is really old and gungy :)

[@MyMiniHomeWorkshop]

I got caught out by the too-deep thing with the first quick-change tool holders I made, and I won't make that mistake again when cutting dovetails. Doesn't that cutter look special when it's spinning fast in your fast-forwarded sections. 👍

[@RotarySMP]

Thanks. Dovetail tool holders need to be surprisingly precise. The take up of the clamp is pretty minimal.

[@angrydove4067]

I LOVE Dove tails!

[@RotarySMP]

So do I, when it works ;)

[@624Dudley]

Hello Mark, I’m still impressed with the shop made dovetail cutter. Maybe more so, now with the upgrades! 👍 Respect for Mrs. Rotary’s tulip rule. I have a similar policy surrounding the daffodils.

[@RotarySMP]

Hi Doric. She says Hi :) The cutter is working well now.

[@624Dudley]

@@RotarySMP Please tell her hello for me! P.S. People are going bonkers around here, getting ready for the big eclipse 🌞

[@RotarySMP]

@@624Dudley We had one back when I was at Lauda Air. Kind of cool, but nothing magical.

[@RotarySMP]

@@624Dudley Hope you had clear skies to see the Eclipse Doric.

[@624Dudley]

@@RotarySMP Halfway at least. We got to the minimum (94% obscuration here) without clouds then they slid right in.

[@Rustinox]

Imagine that everything would work perfectly from the first go. That woul be boring :)

[@RotarySMP]

Hi Michel. Exactly. :)

[@julias-shed]

Nice to get it just right 😀

[@RotarySMP]

Hi Julia. Yeah, it took a while.

[@TrPrecisionMachining]

very good job RotarySMP

[@RotarySMP]

Glad you enjoyed it.

[@E1nsty]

I like how it looks like you're cutting steel with brass when it spins.

[@RotarySMP]

Yeah, I like that gold look as well.

[@Paul-pl4vy]

Great music at the end of the

[@RotarySMP]

Glad you enjoyed that Paul.

[@steveggca]

Nice progress. 👍 measuring between pins like that is one of the many uses for gage blocks .tedious yes, but don't forget that a caliper is =/- .025mm at best.

[@RotarySMP]

Oh, good point Steve. I have gauge blocks.

[@steveggca]

@@RotarySMP besides it's always good to check calipers, micrometers, etc against the gauge blocks once and a while. Side storey.. a few year ago we sent out a brand new starrett caliper and a cheap house brand Canadian Tire caliper for calibration the cheap one passed and the starrett failed.

[@RotarySMP]

@@steveggca I notice that the twenty year old chinese one uses less battery, and is about as accurate as the Mitutoyo, but is slightly less rigid, so you see more spring in the frame and need more consistant feel.

[@andli461]

I was sitting like “I’m sure I have seen him using gauge blocks on this channel in the past.” 🤔 Great results and an extra thank you for everything Maho related. (Still haven’t managed to get my hydraulics to latch on…and no faults found in any E-stop chain. Builds pressure though. That goes away almost in an instant. No fluid mess to indicate a leak. New check valve at the solenoid/valve block. 🤷‍♂️)

[@RotarySMP]

@@andli461 On my conversion, I don't have it wired to hold hyd Px. I just have it run the pump and build up Px when I push the tool change button. Since I dont have an ATC, I dont see much point having it run the pump regularly.

[@andrewclarke3750]

Nice view of the controls under the flight deck floor. FEC OR MEC? Great video as always. Andy

[@RotarySMP]

Since I mostly worked on Boeings, I can never remember Airbus acronyms :)

[@MattOGormanSmith]

The width measurement wasn't dependent on the depth, you could have just skimmed the top. The depth should either be a hair under or a hair over the depth of the dovetails on the toolpost, depending on the which is the intended clamping face. Most setups use the face of the dovetail so the toolholders would be a hair shallower.

[@RotarySMP]

True, but because I was still in set up mode and have 12 of them to cut, it was easier to get it sorted at the start.

[@hinz1]

Why not disassemble the toolpost on Schaublin and check it against the part, directly on the machine?

[@RotarySMP]

It is on the to do list, but too big a job for right now.

[@davidsamways]

The solution to overspray is stop spraying and use a roller! I stopped spraying machine tools years ago as it's such a pita and the finish with a foam roller is almost as good. Actually, the finish is more approapriate in many ways - slight orange peel much like the original finish. It's all down to the preparation of course. I also use a synthetic white spirit based enamel which is extremely hard wearing and only requires one coat. With a high zinc content the paint can also go over bare metal which means if you rub through the primer on your prep the paint is going to adhere nicely. Still spraying motorcycle parts with 2K though - rollers' just not good enough for automotive.

[@mauromalvezzi534]

Interesting - what is white spirit based enamel? I only knew about alkyd base enamels. I too am a big proponent of either brushing or rolling paint on Machine Tools - can't see the advantage in spraying 2K paints on stuff that will only work indoors.. Thanks!

[@RotarySMP]

I don't use 2K paints, as I don't want that stuff in my lungs, if I dont get a perfect seal on my cartridge mask. I have never had any success rolling on a compound curved surface like that vise.

[@davidsamways]

@@mauromalvezzi534 I'm in the UK and use Johnstone's Smooth Metal Paint - it's a synthetic enamel with a high zinc content. If you take a look at my video series on adjusting Schaublin 102 bearings you'll see the finished machine in the last video.

[@davidsamways]

@@RotarySMP It's really very easy to paint surfaces that are just about any profile. You do need to start with a brush to get into the crevices, but use a sponge roller with a feather edge (concave end) and you won't have any problems. Take a look at the lathe shown in my series on Schaublin 70 and 102 bearing adjustment - the finish is extremely good but dependent on careful preparation of course. A 2K primer-filler can be heavily brush applied before sanding. I agree about 2K being nasty, but applying by brush and wet sanding avoids most of the risk - always wear a good mask of course.

[@ethanmiller5487]

If you get yourself a set of adjustable parallels you will be able to measure inside noncircular features easier.

[@RotarySMP]

Good point, thanks Ethan.

[@chadstrand7868]

thanks for the video

[@RotarySMP]

You bet!

[@dazaspc]

I have no experience with that CNC but with the 24 volt down it was swinging back and forth chasing a M19. Probably has a switch in the spindle somewhere for the index of the spindle. No 24 volt no switch signal. Surprising there was no alarm for it.

[@RotarySMP]

The gearbox shifting software was written by a friend of mine, based on a spec from me github.com/jin-eld/mh400e-linuxcnc/wiki I didn't spec this case.

[@dazaspc]

@@RotarySMP Oh I wasn't aware it had a custom control. I thought the Knock out cycle might have been one used for a machine with an optional tool change. Pretty easy fix if you wanted to just add a 24 volt relay into the feed hold circuit. 99% of cnc's will turn the 24volt on the moment the E stop is released. So it would power up the same. Just go into feed hold if you lost the 24 volts.

[@RotarySMP]

@@dazaspc The Maho is a mix of original wiring and my conversion to LinuxCNC. I have never had that CB trip before, and will just keep an eye on it for now. There are three 24V rails. One is always on, and two drop with E-Stop. I much have the twitching relays on one, and the gearbox shifters on another.

[@MakarovFox]

lovely ring

[@RotarySMP]

Thanks. I will wear it forever :)

[@MakarovFox]

@@RotarySMP that is the way

[@broglet2003]

Another great video. You showed brake disks that you use for casting. Do you need to add ferrosilicon to reduce problems with chill and hard spots in your castings?

[@RotarySMP]

I haven't dont that much, but with thick sections, it works fine as long as the casting cools slowly in the mold. I have not been able to source ferrosilicon (at least less than a ton at a time :)

[@broglet2003]

@@RotarySMP That is good to hear. I cannot find it in small quantities either. I saw that luckygen1001 (was he one of your recommendations?) seemed to use it a lot.

[@tobiasripper4124]

17:07 pay close attention to the right side, i see a small gap. i don't know if thats normal, just pointing it out.

[@RotarySMP]

I will take a closer look. Thanks Tobias.

[@shedtime_au]

Yes, normal viewers can watch live streams. I saw it live.

[@RotarySMP]

Thanks for the feedback on that.

[@LCalleja]

Grate video getting some things done for tool holders. How did you find the new mag base?

[@RotarySMP]

Hi Luke, I really like it. Much easier to set up than the old one. Thanks.

[@LCalleja]

@@RotarySMP Told you that they are addictive:) you nearly have as many as I do now

[@RotarySMP]

@@LCalleja One normal and one enormous :)

[@LCalleja]

@@RotarySMP well a few too many normal then one big one

[@npalen]

When using a triangular shaped insert to cut a 60 degree dovetail, doesn't the bottom of the insert rub on the "floor" of the cut? Perhaps that is not a problem?

[@RotarySMP]

It does, and seems fine, until the insert loosens :/

[@paulwomack5866]

I'm sure you've done the same searches, and discovered the same thing as me. Anyway; EVERY commercial dovetail cutter uses the diamond shaped inserts. EVERY DIY dovetail cutter on youtube uses the triangular inserts

[@RotarySMP]

Excellent summary Paul. I already bought some DCMT's for V2.0 :)

[@paulwomack5866]

@@RotarySMP The only two commercial DT cutters I found: kzbin.info/www/bejne/jqG4dYBmg6iCoqs kzbin.info/www/bejne/pX-Zh56wgNyAi8U

[@alexkart9239]

2:51 of course we always take it off. my lovely cnc baby shouldn't know i'm married.

[@RotarySMP]

It might get jealous. :)

[@LittleAussieRockets]

Dumb question what's in the hard drive that's good for casting? is it aluminium

[@RotarySMP]

Yeah, the frames are a really nice alloy, and very high quality.

[@HanstheTraffer]

Are those harddrives pure aluminum or some alloy?

[@RotarySMP]

They will be a casting alloy. I haven't had them analysed, but they are castings, and likely a typical alloy.

[@blahanger4304]

Is that In betweendays the background?

[@RotarySMP]

No, I can't use commercial music (Unfortunately. The Cure are brilliant). It is from Artlist.IO.

[@hedning003]

flowers in bloom , here it's till snow - got about 15 cm 2 days ago

[@RotarySMP]

It has been another really extreme year here. Hottest Feb, hottest Mar, Earliest 30°C day on record etc.

[@hedning003]

@@RotarySMP you are making me jelous, Marc , especially as i am a biker,and just want the roads to be sidable again

[@RotarySMP]

@@hedning003 You must be pretty far north right?

[@hedning003]

@@RotarySMP As close as i can get it,i am about 1800 km north of you via roads🤣

[@RotarySMP]

@@hedning003 :)

[@thomasfischer6548]

How, where and When you are casting Iron?

[@RotarySMP]

I have a couple of videos on that... kzbin.info/www/bejne/j4bVkodnrZl0qqc kzbin.info/www/bejne/bmK8eHyjiZKgoas kzbin.info/www/bejne/fmnNYaKKapV3r6c I dont cast very often, just when I get the urge. kzbin.info/www/bejne/mJKbhWB3nM6fea8

[@budapest.Lamperth]

Am I right to assume that the producers have cancelled the 16mm camera series?

[@RotarySMP]

It is still lurking on the shelf, glaring at me for not using it. I need to make up a telecine to be able to scan the film.

[@LyallPearce]

Challenge #5, what is the artist and track of the music during the milling?

[@RotarySMP]

The song is called Thunder, by Far West.

[@LyallPearce]

Ah, the track before, I hear 'Thunder' at about the 16:30 ish.... so the track before!

[@ska042]

The blurring at 8:04 kicks in a frame late ;)

[@RotarySMP]

Thanks. I'll adjust it.

[@fldrmaus]

@@RotarySMP and on the previous package there was a phone number visible. That should probably get the same treatment.

[@RotarySMP]

@@fldrmaus That is the selling companies number. Call it advertising.

[@julianweiser9985]

If its chattering like that, increase feed.

[@RotarySMP]

Thanks Julian, I also wanted to reduce engagement.

[@brendanshorter5550]

Do you cast iron?

[@RotarySMP]

Yes Brendan. Not often, but I have a foundry set up in the garden shed. I have a playlist on casting... kzbin.info/aero/PLHRtJd1bD3ITm_OPiV2CvW46Hf6luHMJ1

[@brendanshorter5550]

@@RotarySMP I watched all of them except the cast iron one referenced.. odd. But more for my viewing pleasure.

[@chrismayer8990]

One step forward, 2 steps back. Isn't that always the case? 😅

[@RotarySMP]

For me it is Chris. :)

[@chrismayer8990]

@@RotarySMP Nice to hear that I'm not the only one with this problem. ;-)

[@69uremum]

Can't be good for vibration to have the machine sitting on wood and not leveled.

[@RotarySMP]

True. I need to make up the steel frame with the adjustable vibration absorbing feed for it.

[@Narwaro]

For every other machine I’d be with you but the Deckel/Maho machines are so monolithic and stiff that it doesnt really make a difference because of the gigantic foot. You can probably hang one of these machines on a bar from a crane and still get accurate results.

[@RotarySMP]

@@Narwaro I am still planning to put it onto a raised weldment base, so I can always get the pallet jack under it, but have it sit on vib damping feet. I really like them.

[@MikelNaUsaCom]

third? or first? thx for the video!

[@RotarySMP]

Thanks for watching, Mike.

[@christophbindhammer7925]

Wien is in Austria not Germany

[@RotarySMP]

Correct.

[@joenicotera2991]

You'll notice some places where you don't realize how religious about the mathematics some guys are. That dovetail insert, I assume is one of them. They guy who wrote the book copied the book tat the guy who made the carbide and then the guy who made the tool post simply assumed the only way to do it was to copy the book. And there you are trying to figure out how to get your part to fit the machinist religion. You'll notice the same thing in electronics...only booby trapped sometimes. If you see a transistor that has a little spot of paint on it, look out, because that is what all of the technical jargon leads up to. Transistors have surprisingly few variations within a manufacturers batch but for all practical purposes the could just have a different part number for every batch. The only odd exception is when you stick to the book that doesn't allow your having any say in the adjustment. For instance if you were to design something with a volume control and then decide that it is cheaper to just replace the volume control with two resistors. Take potentiometer out, measure where you like the setting, select those to resistors and solder it in. What you did was you just resigned the device so that it is no longer field repairable. The only way anyone can replace any part in it is with the parts that come from your part bin. Taking that "religion" into account, yours being an aircraft mechanic, let's do a bit of underwriting for a moment. HOW MANY UNDERWRITERS DOES IT TAKE TO SCREW IN A LIGHT BULB IN A 480V MACHINE? Ok now, take your ohm meter and a bit of that coolant from your machine's sump and lets measure exactly how many underwriters it would take.

[@RotarySMP]

Yeah, it is tough to get everything right and everyone happy :)

[@joenicotera2991]

@@RotarySMP Stephan would get the spelling right.

[@jdmorgan82]

Hey… you promised tap carnage at the start of the video. I am disappointed!

[@RotarySMP]

That was a flashback to the previous video... kzbin.info/www/bejne/rKXWnqt-hZx5sMk&

[@theafro]

I did get shown the livestream, but didn't bother watching, i'll bet that your average viewer won't watch livestreams even if they're presented with it.

[@RotarySMP]

That could well be the case. Very different form of entertainment.

[@gamerpaddy]

same here, it was in my sub feed aswell but i dont bother clicking on any live streams on yt.

[@RotarySMP]

@@gamerpaddy Nikolai is a really interesting guy, with a very cool business.

[@Ugly_German_Truths]

The Livestream is watchable, they are just not stored in the Video tab but under "Live" kzbin.info/www/bejne/r6DInWxrq9Zkirc

[@RotarySMP]

Yeah, I think that is way they often get overseen.