Best way to "hold" a throating reamer

[Shawnba67]

I am about to purchase a 6mm throating reamer(not a uni-throater) and am interested in your opinion on the best way to use it. My initial intentions are to use it in the lathe during chambering process. I worry about its ability to self center with such a small cut being taken, there is obviously a way around this since their use is common and outcomes good..
THANK YOU for any guidance

 

[paperpuncher]

Heres what I do and this might be way off base or overkill so Ill get my fire retardant suit ready. I have a tube that threads over the tennon about 3" long 1.5" od it is bored about .875" on the end opposite the thread. I have bushings that are .875"od and about .400"id, the bushings sacrificial and are held in the tube with a small set screw. Once chamber is done I screw the tube over the tennon and insert a bushing lock it in with set screw. I single point bore the bushing to the same dia as the shank on the throater in my case .437" polish id of bushing for a slip fit. I use the bushing to align the throater and just use my reamer pusher to hold it. I use the collar and bushing because I am not crazy about just holding the throater with the pusher since it could deflect with shank end of the throater being mostly unsupported. I suppose you could just push it with the tailstock and a center as long as the tailstock is in good alignment. Be cautious when cutting the throat the reamer cuts very easily and you can go too deep if youre not careful. A stop collar on the reamer might be a good call. FWIW I checked my throaters on my bench center and the shanks are concentric with the cutting surfaces on mine

 

[Will Henry]

If the throat portion of the barrel is running absolutely true, there is no reason not to simply hold the reamer on the tailstock center and drive it with a tap wrench. I just lay my finger on the shank of the reamer and I can tel when it first touches the lands. From this point, I just watch the graduations on the tailstock handwheel to cut to the desired depth. It is important to hold the reamer back tight against the center while reaming and feed steadily. The last ten thou or so, the reamer should be fed in very, very slowly. WH

 

[Shawnba67]

Thank you for the advise given. My tailstock is slightly high and no easy way to fix that on this particular lathe.

 

[Riesel]

OK, I don't have a lot of experience with this but I have done a couple and I do it this way. PT&G and probably others have a reamer stop collar that is used on a reamer to maybe prevent you from going too deep. I use a T handle and this device. Remove handle portion from T handle, slide the stop collar on, replace handle. You will need to have barrel properly headspaced and tightened and with triggerless action installed. Fasten throat reamer into T-Handle and insert thru action and into the chamber. Use your best fitting bushing to the reamer. Slide stop to rear of action and make sure reamer is settled nicely in the chamber/throat. Using a feeler gauge with the correct depth that you would like to remove, insert between stop collar and rear of action, tighten set screws. Remove everything, give reamer a good coating of cutting fluid, re-insert and turn throat reamer, in the proper direction slowly and gently. IT WON'T TAKE MUCH. You are removing very little material, just a little off the back of the lands. Be absolutely sure you know how much you want to remove by using whatever OAL means that suit your fancy. Remember, once this is removed there is no putting it back on.
This is a pretty simplified way and it works for me, hope it works for you.

 

[Will Henry]

Regarding the slightly high tailstock: This is common and I have been told by various reps that it is deliberate. Let your lathe run until the headstock is warm and the height difference disappears. This is certainly the case on my lathe. WH

 

[Shawnba67]

Regarding the slightly high tailstock: This is common and I have been told by various reps that it is deliberate. Let your lathe run until the headstock is warm and the height difference disappears. This is certainly the case on my lathe. WH

i have never thought to recheck it once warm. I will do that but as a hobbyist it doesn't get fully warmed up often.

 

[Ggmac]

Wrap the head in a heating pad hooked to the light switch . Up north we had them on most machines , even though the shop was heated( warmed ) during the day , at night it would go down to 40 ish . So the heaters were turned on which the light switch and by the time came to start work the oil and important parts were at NOT , normal operating temperature .

 

[gat]

My opinion differs from many but my best results occur when I hand turn the throater rather than doing it in the machine. Too small, too fragile and too expensive to replace because of an uh-oh moment!