turning between centers question

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trooperjd

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I prefer to turn between centers. I have several roller kits that bushings are not available for turning between centers.

My question is can I use the bushing available for turning on a mandrel, and just turn them between centers.

If this question seems quirky, sorry new to turning between centers so figured I turn to you guys.
 
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First...ask John if he has them or is willing to make them. Second...stock bushings are 50% of the problem...is the hole square, is the bushing round? I think that if you order 5 bushing sets, you will get 5 different measurements. Others may have other happy stories, none of mine have been...just MHO
 
Sure you can, but you can make them seat better in the centres, by centre drilling the ends. If you do this, they will be more accurate and you will need less tailstock pressure.
 

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I just ordered and recieved my 60 degree dead center from Johnnycnc this week and asked the same question. He told me you can but you will not get the best results.
 
Yes, you can use them. The results may not be as good as with TBC bushings. There are several ways to do it:

1 - Just put the centers into the holes as they are. Quick and easy, but the least accurate way to do it.

2 - stick slimline TBC bushings in the regular bushing holes. Better than the first way, but your accuracy is only as good as the bushings.

3 - Use a drill center to put a 60-degree chamfer in the holes. This gives you a taper to fit the live/dead centers for more grip and better self-centering. Don't trust the wide part of the bushing to be round or centered - chuck to the part that goes into the tube, and use the most accurate chuck you have. It's conceivable this could even compensate for an off-center hole!

I started out doing (1). I'm gradually replacing my bushings with TBC bushings, but for any I haven't replaced yet, I use (2) with decent results. I also use the slimline bushings and calipers for all 7mm tube kits.
 
Drilling Bushings?

Steve,
I have the same problem. Pen kits that Johnny does not make bushings for. What do you use to drill a 60 degree angle with, never used the type of drill bit you showed in the pic, and how do you do it. Drill press?
 
GregMuller said:
Steve,
I have the same problem. Pen kits that Johnny does not make bushings for. What do you use to drill a 60 degree angle with, never used the type of drill bit you showed in the pic, and how do you do it. Drill press?
Click to expand...

That short drill is called a centre drill. You can buy them individually or in sets. I drilled that bushing on a lathe a while ago just to show the concept.
When I need bushings, I make them myself from stainless and they extend down the full length of the tube.
 
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GrantH said:
I've started to not even worry with bushings. Two pens down and they both have been far better than those I turned with bushings between center or on the mandrel. I'm bushingless now as far as I can tell.
Click to expand...

I don't use bushings either, haven't seen any evidence that I'm at a disadvantage yet.
 
For me, the only purpose/advantage of bushings is to get close to final size quicker. I have TBC bushings for the components I use most often, and use them when rounding the blanks, then turn down to a good bit above the bushings (usually around .050" over or so for you scientific types...). Then I pull the bushings, drop the blank strait between the 60 deg centers and finish turning to size with calipers. For the components I don't have or can't get bushings for, it just takes a little bit longer to turn down since I have to stop more often to measure as I don't have the bushings to help me get close...
 
I got a set of the .515 bushings that Penturners Products sells,( only 1 set per customer ) that you just slide the 7mm bushing on the shaft part,and they work great for the odd-sized bushings.The tolerances are EXACT,just like everything John makes.
I sure am happy with the set I got,maybe check it out before they are gone?

Steve
 
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