Bob's Home Made Bait Injector - 17.8881 in³ = 9.91202 fl oz(US)

I made three of these indentical, but alas I screwed up the nozzle on one (not in this picture). I cut the hex on the nozzle on the little MaxNC CNC mill I retrofit a while back. I also cut the end of the nozzle and the slope on it since I already had it centered on that machine. Then I did most of the rest on a mini lathe. I used a drill press to drill the nozzle, rod guide, and the back of the piston. Threading was done by hand with a thread cutting die. The hardest part (And how I screwed up the other nozzle) was putting in the stupid little locking pin. I have that figured out now though so it will be easier next time. Now to get back out in the shop and make a nozzle for that third injector.

Actual real volume is:

17.8881 in³ = 9.91202 fl oz(US)

However, I can easily cut a longer tube to make any size injector I need now. Just swap the guts.

I did discover I needed a lot less engagement on the piston O-ring than I originally thought, and I had to cut the O-ring groove deeper to reduce friction.

Before anybody picks on me:

1. I am not a real machinist.

2. My mini lathe is a prety crummy piece of equipment.


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Oh, yeah. I could have made the little ball for the handle, but all I had was aluminum (hot) or acetal Delrin (expensive). I bought them off Ebay for $3 each shipped only to find out they were less than $2 each from McMaster. Oh well. LOL.

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Nice Job I knew you had it in you. What is the diameter of the tube? Is the wall .125? Frank

1.75" ID. 2" OD. .125 wall. I thought about going with thinner tube, but it just gave me the heebie jeebies. I have a Jacobs injector, and it is thinner tube, but I just didn't feel comfortable with it myself. Besides. I had this tube on hand.

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Well done, Bob! Excellent job!

What do you figure that totals in cost - materials, time, cutting operations, etc...? :?

Oh, I could sell them for a few hundred dollars a piece if I only paid myself minimum wage. LOL. Seriously, I didn't see an injector big enough for some of my molds, and I had this metal on hand already left over from another project.

I guess Kevin just came out with a 10oz injector, but I didn't know about it until after I had finished these.

Actually, I have not done a cost on them since I used all left over materials, but now that I have made a few I imagine I could make them for about the same as anybody else.

The best thing though is that I can use my already cut hardware and with only minor work make bodies any length I want for larger or smaller injectors now.

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