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tackit
03-09-2015, 12:39 PM
I want to substitute Delrin for the aluminum pieces on this sight pusher but I have never milled plastic before, can someone that has give me a few pointers and the speed and type of mill I should use. Thanks for any help.




http://i1298.photobucket.com/albums/ag44/cyberjibe/sight%20pusher/0_0_0_0_223_167_csupload_47311542_large_zpsba9nj3w v.jpg (http://s1298.photobucket.com/user/cyberjibe/media/sight%20pusher/0_0_0_0_223_167_csupload_47311542_large_zpsba9nj3w v.jpg.html)

Toolguy
03-09-2015, 12:55 PM
I make a lot of Delrin parts. It's super easy to machine. You want to use cutters with high back clearance so they don't rub behind the cutting edge and generate friction and heat. Some of the desirable cutters are 1, 2, and 3 flute end mills and carbide tipped wood router bits. For smaller parts like that the 1/4" shank router bits are fine. For larger parts and cutting alum. the 1/2" shank ones are a lot more rigid.

I usually run between 2000 and 3000 rpm. If you go too fast without coolant you will melt the plastic. For drilling, I usually run around 1000 rpm.

Euph0ny
03-09-2015, 01:02 PM
I want to substitute Delrin for the aluminum pieces on this sight pusher...

Not about the milling, but the material - unless your sights are particularly loose, I'd have my doubts about Delrin standing up very well to pushing them. If you're worried about the aluminium marring the sights, how about putting a thin layer of Delrin, or plastic tape, or a piece of cardboard in-between?

Toolguy
03-09-2015, 01:15 PM
I'm thinking we're talking about the parts on the bottom holding the slide.

tackit
03-09-2015, 01:37 PM
I'm thinking we're talking about the parts on the bottom holding the slide.

Toolguy you are correct sir....

Euphony the pusher is going to be made from brass.

I have money invested in tools, might as well use them, this wouldn't be the first project which ended up in the garbage can, and I can guarantee it wouldn't be the last.. Nothing ventured nothing gained. :)

Toolguy
03-09-2015, 03:38 PM
Delrin will work great to hold the slide. You may want to think about bronze for the pusher. Brass may work for a while, but I thinks will get deformed fairly quickly.

tackit
03-09-2015, 05:07 PM
Delrin will work great to hold the slide. You may want to think about bronze for the pusher. Brass may work for a while, but I thinks will get deformed fairly quickly.

Toolguy I chose brass because I have some on hand...the pusher won't be used that often, only to change the sights in my pistol and to sight it in. If the pusher works like a clock works and guys down at the plant where the SIL works would want one I wouldn't mind spending money on bronze. Thanks for your input Toolguy, I appreciate it. :)

Billy Hill
03-10-2015, 12:07 AM
Delrin will chip if you aren't careful. When cutting, always try to have the flutes cutting into the material, not breaking out of it.

Drills should be 135 degrees, not the standard 118 degrees that are used for metal. This isn't always an issue but is worth bringing up.

Cool looking fixture, BTW!!!

Euph0ny
03-10-2015, 07:02 AM
Euphony the pusher is going to be made from brass.

My mistake. Apologies. Delrin side blocks and a bronze or brash pusher should work fine. Happy shooting! What kind of pistol is it?

tackit
03-10-2015, 09:47 AM
No need to apologize Euphony, glad to have communicated with you on the board, I appreciate all help and encouragement I can get. :D

The pistol is a XDm 40 cal.

Pics of the gun and the my version of a pusher body, I want mine longer to prevent the slide from twisting in the pusher. Click on the gun pic and arrow and the pushers body will show up.


http://i1298.photobucket.com/albums/ag44/cyberjibe/XDm/XDm%20LSide_zpsyxqtfbnm.jpg (http://s1298.photobucket.com/user/cyberjibe/media/XDm/XDm%20LSide_zpsyxqtfbnm.jpg.html)


Got the body of my version done, just waiting for the Delrin and slide clamp from Brownells to continue.

tackit
03-10-2015, 09:50 AM
Delrin will chip if you aren't careful. When cutting, always try to have the flutes cutting into the material, not breaking out of it.

Drills should be 135 degrees, not the standard 118 degrees that are used for metal. This isn't always an issue but is worth bringing up.

Cool looking fixture, BTW!!!

Thanks Bill, I appreciate the information, I'll be using it shortly. :)

Euph0ny
03-10-2015, 04:41 PM
The pistol is a XDm 40 cal.

Very nice! I believe I handled some of those as display models at the IWA in Nuremberg last year. They seemed solidly made.

Happy shooting!

tackit
03-10-2015, 06:01 PM
Very nice! I believe I handled some of those as display models at the IWA in Nuremberg last year. They seemed solidly made.

Happy shooting!

I'm not familiar with striker ignition systems, after reading about Glock ADs I feel better with the XDm's grip safety.

Euph0ny
03-11-2015, 11:39 AM
You might find this interesting - NYC CNC just made up a sight pusher like yours. Warning, machining content!

Part 1 - https://www.youtube.com/watch?v=iB3NYkZFMJY
Part 2 - https://www.youtube.com/watch?v=WM2bOTriBNg

If you don't want to watch the CNC part, skip to 9:50 in Part 2 for the assembly and testing phase.

tackit
03-17-2015, 08:13 PM
Sorry for not getting back to you sooner Euphony, I've been busy. After a week of waiting for the 1 3/8 annular cutter from CSUnitec I called them only to find out the CC # didn't go through..... seems I gave the man the wrong number or he wrote it down wrong over the phone, naturally the woman that takes care of such problems wasn't there, if I hadn't called I would still be waiting for the cutter. Anyway I have it now in my possession and will start cutting the larger pin holes in the press legs after I finish the sight pusher.


I thought about capturing the sight in a notched pusher but DXm sights from the factory have a reputation of being very hard to break loose so I chose to use a nub that goes almost all the way down to the slide.

I used a 1/2 X 13 125,000 PSI B7 flange stud instead of short piece of hardware althread, the pusher moves across the flange stud with just a bit of drag, not having any axial or radial play whatsoever.

I used a hack saw, a SS scraper, a flat mill file, Norton 8" X 2" combination stone and the tools in the picture to rough out the pusher. when I'm finished stoning the pusher with the Norton stone it should be perfect in all dimensions.

I still need to fashion a bottom Delrin plate and two 1/4" thick Delrin side plates/bumpers to protect the slide in case the prototype is flawed, cut the pusher down to 5/8 from 1" and mill a slot in the Delrin bottom plate to hold the DXm Slide clamp.


http://s1298.photobucket.com/user/cyberjibe/slideshow/DXM

spongerich
03-17-2015, 08:40 PM
I haven't machined a ton of Delrin, but with what little experience I have had, I found that keeping the feed rate high helps prevent chip loading and melting.

tackit
03-17-2015, 10:25 PM
I haven't machined a ton of Delrin, but with what little experience I have had, I found that keeping the feed rate high helps prevent chip loading and melting.


Thank you spongerich, I'll remember that.

I might try using a router table with a plastic cutting bit to cut out the 1/4" thick side panels and floor plate. I hoping if I make the Delrin floor plate tight to the pushers sides when I tighten the slide clamp down it will hold the floor in place too. I'm also going to use a 1/2" Nylon cap screw on each side of the frame towards the back to keep the slide from twisting. It all sounds good, now if I can pull it off.