I have the exact opposite trouble as Rackattack. My ACC 3-49 inserts seem to shallow.

I didn' t really notice much of a problem until this spring. I shoot a 75 grain field tip and 75 grain Rocket wolverines, and they go in just fine. However, I recently wanted to see what a 100 grain head would do, so I tried to screw in a 100 grain field tip. It lacks seating against the insert by about 1/8" . For chits and giggles, I tried to screw on a 75 grain titanium steelforce, same size as the 100 grain but made of a lighter material. Same problem, won' t fully seat.

Basically it appears the insert depth before the threads are engaged is too short. Is this a common problem with these inserts? Am I " doomed" to shoot Rocket heads the rest of my life? Did I get defective inserts?

You have probably already covered this, if so I apologized for the repetition.

Assuming you tried this with the insert already glued to the shaft, there is a possibility that excess glue is blocking the rear threads in the insert. I have seen this occur a number of times. ACC inserts usually run in line with the AMO standards.

Just a thought.

Actually the inserts are now out of the shafts, and glue doesn' t appear to be the problem

If I hold the 75 grain and 100 grain field tips side by side, while they are identical in overall length and the length of the threaded section, the 100 grain doesn' t have as many threads as the 75 grain, by the same amount the tip won' t seat. I thought maybe it was just these tips, but surely the Steel Force would be able to seat in these inserts, as I' ve never seen this problem discussed anywhere else.

Ok, just tried some other heads I have lying around. 100 grain Wasp Jackhammer SSTs fully seat, no problems. So do the 100 Grain Stainless Steel Steelforce...

I' m gonna check all the inserts, maybe it' s just one or two giving me fits. I haven' t checked them all.

Ok, work be damned...

I went next door where I keep my bow and got all my inserts (the hot melt they were applied with did a poor job, they spun in the shaft so I took them out to re-insert with 24 hour epoxy).

The wasp and 100 grain steelforce fully seat on each insert. The 100 grain tip and 75 grain steelforce do not. The threaded shaft of the two steelforce heads appear identical, but apparently, they are not. The Wasp threaded shaft is actually about 1/16th" longer than the field tip that won' t fully seat.

I' m at a loss as to what' s going on...

RB,

I can' t say I' ve ever had or seen this problem, unless it was the " too much glue" issue. I' ve never had any problems getting alot of different heads on an ACC 3-49. Wasps, Rockets, Muzzy, T-Heads, Gametracker, Barrie, Phantom, Steelforce..I' m sure I' ve forgotten several.

However I' ve seen plenty of field points that are poorly made and won' t always thread correctly.

I would try some different brand type field points and see what happens. Although it' s possible that there is something wrong w/ the inserts, you say the Jak-hammer fits fine, and this leads me to believe there is an inconsistency in the threads of those tips/heads that won' t seat fully.

You may just also want to invest in a dozen new inserts (minor cost) and see what happens. If the same thing happnes with the new inserts, you can assume the anomaly is in the heads/tips.

If I were to hazard a semi-educated wild arsed guess, I' d say the threads in the inserts were slightly pushed back by the itty bitty Rockets just enough to misalign the shallow threads with the deeper threads in the inserts. That' s the likely cause of why the longer shanked heads won' t fully seat.

Arthur, the Wasp head is the longest shanked of them all, and it seats just fine...

Sorry to bust your bubble. Of course you did say semi-educated, just not to what level

Well, if I had the heads, inserts and a full compliment of precision machine shop inspection equipment, I could tell you what the problem is. Maybe the theaded shank on the Wasps is slightly undersized and lets them get past the boogered up part of the threads. Who knows.

Head on off to the hardware store and get an 8-32 UNC-2A tap and chase the threads in the inserts. Might be cheaper just to get new inserts though.

Art, I' ve no doubt you could figure it out. I' m gonna check with my Grandpa first, I swear he has 3 of every tool made

By the way, I understand the 8-32, but what does the UNC and 2A stand for? All his chit is at LEAST 30 years or older...

The UNC stuff is just a standard thread designation. Threw that in just to be a wise guy. Come to think of it, the A designation is for an outside thread for a die and B is the designation for a inside thread for a tap. I screwed up anyway. That' s what happens when you' re out of the trade for 13 years.

Anyway, just a regular ol' 8-32 tap is what you need.

But I' d bet my last dollar that the problem is in the threads because that' s the only thing supporting the jolt of the impact from the broadhead hitting the target. You don' t have but maybe two, maybe three threads holding those Rockets in place. That' s not a lot of metal to resist bending. And by my measurements, the Rocket shanks are exactly 1/8" shorter than the other heads I' ve checked.