[ 3 / biz / cgl / ck / diy / fa / ic / jp / lit / sci / vr / vt ] [ index / top / reports ] [ become a patron ] [ status ]
2023-11: Warosu is now out of extended maintenance.

/diy/ - Do It Yourself

View post   
File: 246 KB, 1078x808, IMG_1186.jpg [View same] [iqdb] [saucenao] [google]
1086461 No.1086461 [Reply] [Original]

How do I secure this piece of delrin for flycutting?
Some sort of glue?
Clamping it in a vise deforms the edges and it still moves.
I need the glue to not be there when I'm done tho...

>> No.1086469

>>1086461
Delrin is a great material but a real bitch to work. I'd glue it to something more stout then machine the glue off later.

>> No.1086471

>>1086469
would laying it down on a flat surface and running a bead of hot glue around the edge be sufficient?

>> No.1086475

>>1086461
flycutting what? making it thinner? no lathe?

stick a threaded rod in it to cut the perimeter then clamp edges to finish it off

you're gonna spend a lot to glue delrin

>> No.1086514

>>1086461
glue it down with red loctite, use a solvent to clean up the loctite after your done

>> No.1086544

>>1086514
does that actually work? might try that next if the hot glue doesnt hold well enough

>> No.1086546
File: 567 KB, 1632x1224, IMG_1187.jpg [View same] [iqdb] [saucenao] [google]
1086546

Here is what i've come up with so far...
the stud through the center of the part will be removed after i glue the perimeter

>> No.1086554
File: 463 KB, 1632x1224, IMG_1188.jpg [View same] [iqdb] [saucenao] [google]
1086554

>> No.1086555
File: 505 KB, 1632x1224, IMG_1189.jpg [View same] [iqdb] [saucenao] [google]
1086555

it didn't work

>> No.1086557

>>1086461
Two sided tape.
Seriously. I've even done this for metal parts before.

>> No.1086562

>>1086557
Metal is much stickier than delrin.

>> No.1086566

>>1086562
apparently not with hot glue, look at the last pic
mind you the delrin was rough where it stuck

>> No.1086596
File: 642 KB, 1224x1632, IMG_1190.jpg [View same] [iqdb] [saucenao] [google]
1086596

lmao

>> No.1086626

>>1086461
Can you make a tight fitting fixture? If you have a hole that is a tight fit in a piece of aluminum and use glue with that, it should be harder to knock loose.

>> No.1086632

>>1086596
So you cut it into a gear, and then the gear failed?
What is that supposed to drive

>> No.1086639

>>1086632
thats the intermediate gear between the motor and the spindle. when the hot glue failed and the part lifted the fly cutter stopped suddenly and shattered the gear. I've already placed an order for a belt drive conversion, thats a shit design.

>>1086626
probably. I'm going to try cutting my delrin parts oversized to allow for some recessed flat spots for clamping first.

>> No.1086646

>>1086469

>real bitch to work

Are you kidding me? Delrin/Acetal is handily the best plastic I've worked with. It doesn't leave flanges on cut edges like HDPE/UHMW does, it doesn't tend to overheat like PVC, it doesn't grab like nylon, and it doesn't produce fine flakes and dust like PTFE. Just cuts smooth and chips well.

...is there a reason you can't just cut some arcs of the same radius into a pair of scrap pieces, and stick those between the vise jaws and workpiece to get more holding area?

>> No.1086709

>>1086566
That's because delrin is thermoplastic like hot glue. Double sided tape was brought up. For PSAs, metals are magnitudes stickier than plastics.

>> No.1086733

>>1086546
Just mount that bolt in a drill chuck and clamp your flycutting bit to the table. Use your mill like an upside-down vertical lathe.

>> No.1086741

>>1086733
This is exactly how im doing the edges, but it doesnt work so well for the face surface. also i cant get under the washer in the middle

>> No.1087494

>>1086544
ive never glued to the mill table, but i do glue thin stuff to the jaws of the lathe chuck like this regularly, superglue might work as well

>> No.1087543

3 dots of black loctite super glue around the bottom of the part, glue it down to sacrificial plastic or metal of your choice, held in vice. You can skim the substrate before gluing and you'll be very flat and square to your machine ways.

Light cuts with damn sharp tool. When done a sharp smack with a hammer on a wooden block against your part will release it. Clean residual glue off with acetone.

This works, I've done it and gotten paid for it. I usually use thick plexi as a sacrificial substrate for glued down parts. In the event you use too much glue you can warm the plexi on a block of metal on a hot plate on low or soak in acetone. Plexi will die delrin lives. Best to go light on the glue and smack it though.

>> No.1088296

Lightly rough up the bottom with some 100-150 grit sand paper and just glue it down with super glue. Or go to the hardware store and buy outdoor mounting tape, which is the same kind of tape they use to adhere skyscraper windows in place. If you go with the tape, clean both surfaces to within an inch of their lives with acetone and then don't touch the surfaces with your grease fingers.

Bonus technique, make an expanding arbor that will thread into a t-nut and put a flat head bolt in the arbor to spread the arbor inside the hole you have in that delrin puck. Like a collet in reverse.

>> No.1088341

>>1086461
Double sided tape. Place it in a flat sheet of metal. Clamps another sheet of metal to the top side as hard as you can. C clamps or if you have an arbor press. Then vise clamp the sheet of metal its stuck to and mill the face. Take light cuts and you are fine. Knock it off the tape with solvent or a sharp putty knife.

>> No.1088560
File: 31 KB, 300x181, W1078[1].jpg [View same] [iqdb] [saucenao] [google]
1088560

>>1086546
>>1086555
>>1086461
Machinist fag here,
If I were to clamp a part like that, I would have used a hex bolt and a nut with some washers to go in the T-slot.
And then use pic related like an expansion plug to keep it in place.
keep cutting forces low, and preferrably downwards cutting forces

>> No.1088596

>>1088560
And how does the fly cutter avoid the wingnut? Usually flycutting (less than ideal milling situation) is implemented so to whole surface gets hit at once. Yes I suppose he could manoeuvre around it but then he could do that with a little 3mm endmill too and hold the part down with precum.

To the OP - you do know that any tram errors are magnified with a larger radius cutter right? If you want flat you need to be sure your mill is titsy. If you go for final flat lapping you'll be happier with a lot of shallow out of tram ridges from a small cutter than a big trough from a large one.

>> No.1088603

>>1088596
thanks for the tip, i may switch to a 1/2" endmill or something.

>>1088296
sanding plastic produces a shit finish. if i wasnt worried about the finish i'd just sand the damn thing to the thickness i need in the first place.


i've got a few ideas to try next but i'm still waiting on my belt drive conversion to arrive

>> No.1089020

>>1088596
Well you get rid of the weird wing nut and make sure the bolt is below the cutting surface