Powerfeed Help - Carriage Binding

Dirtbmw20

Dirtbmw20

Lee Casto
Silver Member
:confused: I'm not really sure how to ask this question.... or even WHAT question to ask, so I'm going to explain my problem and hopefully some of yall out there have run into this before or might have a recommendation for me.

Here is my problem.

I added powerfeed to my lathe a week or so ago but for WHATEVER reason my carriage will bind up everytime and basically ruins my powerfeed. It is not "breaking" my pinion gear but it is messing it up pretty bad :angry:. When this happens my pinion gear gets bound up and won't budge. It won't move left, right, or even come out of the eccentric. I literally have to loosen the set screw on the eccentric, take the eccentric out and remove it with the pinion gear still stuck in it and beat the pinion gear out with a punch. Once out I can take the pinion gear and hit it with some 400 sandpaper and it will slide back in the eccentric but I am still getting major binding on my carriage and don't know what to do to correct it. :confused:

I have added a delrin gib, lightly lubed the gib, lubed under the rail where the gib slides, and also the bed itself. I am not running a router or anything, just a simple test of the powerfeed to see how fast/slow it moves so there is NOTHING on the carriage, not even a toolpost so there is no added weight. I have also loosened every single set screw that would hold the carriage in place so there is ZERO chance of any screw holding it tight on the bed. Even with the handwheel it has never been EXACTLY smooth but it also has never bound up or had problems moving the carriage until I added the powerfeed. The motor and pinion gear is coupled with an aluminum flex coupling and I have also tried to make my own delrin coupling to connect the motor to the pinion (thinking the "flex" coupling was flexing too much) but am still having the same problems. I can't make one full pass down the lathe bed without the carriage binding up and coming to a complete STOP using the powerfeed. The powerfeed motor is supported VERY good with a bracket, however, it does this same thing with OR without the bracket supporting the powerfeed motor so I am 99% sure it is not a mounting problem with the motor.

Any suggestions and/or recommendations ???? :frown:
 
duju5e9y.jpg


Here is a pic of what I am using. I have tried the flex coupling that is attached and also the delrin coupling sitting next to it, thinking the flex coupling had too much flex. The delrin coupling gave it zero flex but it didn't help my problem.

Lee Casto
 
Please don't be offended however the taig dovetail system is not a good system to power feed. Sooner or latter you will have issues.

Jim.
 
Mc2 said:
Please don't be offended however the taig dovetail system is not a good system to power feed. Sooner or latter you will have issues.

Jim.
Click to expand...

LOL. Not at all offended Jim and I agree with you but there are too many people using a powerfeed system on a Taig lathe for it to not be doable. Looks like my issues are starting sooner than later.

How else is everyone else (that uses a Taig lathe) traveling the carriage down the lathe bed while tapering if they aren't using a powerfeed system ?? Do many use the handwheel and just not use a powerfeed system at all ???
 
The carriage is not very wide. Get your load as centered over the bed as you can. The carriage may be twisting in you.

Jim
 
I don't see a lock down bracket on the powerfeed unit you built. My first guess would be the eccentric is adjusted to set the pinion gear teeth too deep into the rack teeth.
 
I use the same setup on my hightower and when I first started, I had several issues with mine just bc I didn't know what I was doing.. If it turns fine when its not attached to the bed, it could be several thing.

-make sure the pinion is the correct size and amount of teeth for your bed.
-make sure the coupling isn't rubbing against the outside of the bed
-the pinion could be pushed in too far and rubbing against the back of the wall
-the pinion needs to be straight and not tilted down at all or it could be putting downward pressure on the gear bed
-does the motor have enough power to turn it
-it might help to have a support mount like the one on the hightower lathes that holds the powerfeed perfectly still

other than that, I usually just put the powerfeed in and watch it as close as I can to see whats causing the issue. a lot of trial and error, but there are only so many things that could be keeping it from moving. I'm pretty new to this as well, so none of this might help you. good luck
 
Mc2 said:
The carriage is not very wide. Get your load as centered over the bed as you can. The carriage may be twisting in you.

Jim
Click to expand...

Jim, I have NO load on the carriage at all, I am just doing test runs to see and make sure it was working. Hell, I even took off the slide and compound slide and am using JUST the carriage with nothing on it at all.
 
cueman said:
I don't see a lock down bracket on the powerfeed unit you built. My first guess would be the eccentric is adjusted to set the pinion gear teeth too deep into the rack teeth.
Click to expand...

Chris, I do have a lock down bracket, it's just not in the picture I took. It holds the powerfeed motor very straight and stable.

Your statement about the pinion gear too deep in the rack makes sense, although I have adjusted the eccentric over and over trying to get it right.
 
Justin RC said:
I use the same setup on my hightower and when I first started, I had several issues with mine just bc I didn't know what I was doing.. If it turns fine when its not attached to the bed, it could be several thing.

-make sure the pinion is the correct size and amount of teeth for your bed.
Pinion is the correct one, correct size and correct amount of teeth.
-make sure the coupling isn't rubbing against the outside of the bed
Coupling isn't rubbing on anything, triple checked that.
-the pinion could be pushed in too far and rubbing against the back of the wall
THIS I will have to check. It's the same depth as on my handwheel, BUT that doesn't always turns that easily like I THINK it should.
-the pinion needs to be straight and not tilted down at all or it could be putting downward pressure on the gear bed
Pinion is straight. That is also one of the reasons I tried the delrin coupling, thinking the other coupling wasn't straight or flexed too much.
-does the motor have enough power to turn it
The motor has PLENTY of power to turn it. That is the most commonly used motor for the powerfeeds.
-it might help to have a support mount like the one on the hightower lathes that holds the powerfeed perfectly still
I do have a support bracket, it is just not shown in the pic.

other than that, I usually just put the powerfeed in and watch it as close as I can to see whats causing the issue. a lot of trial and error, but there are only so many things that could be keeping it from moving. I'm pretty new to this as well, so none of this might help you. good luck
Click to expand...


When I FIRST tried it, it ran several passes down the lathe with no problems, then all this started when just doing some test runs to get my speed down correctly. During initial testing, the FASTEST it would move the carriage is 24" in 22 seconds, the SLOWEST it would move the carriage is 24" in 7 minutes and 55 seconds and is infinitely adjustable at any speed in between.
 
Some pictures just for reference in case anybody needs to see what I am up against. YES, I know there are scratches on the underside where the pinion gear rides up against the lathe BUT those were there when I bought the lathe used. It is VERY possible that they have gotten worse since I have owned the lathe, but I just want to assure everyone those marks/scratches weren't made by testing the powerfeed motor out.

I also know the motor is resting/sitting on the table and it has no support bracket on it, it was just "sat" there for pics to be taken. HOWEVER, that is about as straight as it is when the support bracket is bolted up. I can take any pic from any angle if you want to see a different pic of something else.









 
Lee is that dovetail cast iron or aluminum, hard to tell from the pics. Mine is aluminum and I get binding with it if I try to get too much use between cleanings, and I've heard the cast iron dovetails don't work as well as aluminum, but can't say from experience. I use the lube oil and delrin gibb that Basil sells and it moves pretty free but only lasts about an hour or so with heavy use between cleanings. Also, make sure your gibb is adjusted well so there is no loose play in it. Try twisting it in a rotary motion as well as up and down to make sure there is no free play working against you. I think the better solution for the taig style lathe is a feed screw and halfnut setup, but I don't have one. One other thing is keep the rack gear very clean fron chips and sawdust as well as the pinion teeth. Also, there are different pinions available, so make sure the teeth match the rack precisely.
 
Renegade_56 said:
Lee is that dovetail cast iron or aluminum, hard to tell from the pics. Mine is aluminum and I get binding with it if I try to get too much use between cleanings, and I've heard the cast iron dovetails don't work as well as aluminum, but can't say from experience. I use the lube oil and delrin gibb that Basil sells and it moves pretty free but only lasts about an hour or so with heavy use between cleanings. Also, make sure your gibb is adjusted well so there is no loose play in it. Try twisting it in a rotary motion as well as up and down to make sure there is no free play working against you. I think the better solution for the taig style lathe is a feed screw and halfnut setup, but I don't have one. One other thing is keep the rack gear very clean fron chips and sawdust as well as the pinion teeth. Also, there are different pinions available, so make sure the teeth match the rack precisely.
Click to expand...

Frank...... the dovetail is aluminum. Or at least I'm pretty sure it is because it's not that heavy. I had actually never heard of cleaning/lubing the carriage or bed until I read Kim's thread on cleaning HIS lathe. I saw he mentioned about installing the delrin gib so I bought one too, to see if that helped. ...... and it didn't, lol. I was also wondering if the lead screw type would be any better but like you, I don't have that style. I have triple checked the pinion itself and it is the correct size and gear pitch.

Lee Casto
 
P1040118_zps9e2b1444.jpg

Dirtbmw20, Read the PM I sent you. I could be wrong but I don't believe that the problem you are having has anything top do with the carriage, the dovetail or anything except the pinion binding against the U Channel on the side of the lathe bed.
 
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I think the most likely problem is that this is a "used" lathe and has been used almost exclusively right in front of the headstock.
Most all lathe carriages operate in the "sweet spot" in an area right in front of the chuck 90% of the time. Many used lathes exibit wear in this area that you can catch with a fingernail or even see with the naked eye in this "sweet spot" area of the bed. This is a problem because if you adjust the gibbs to a nice working tension in the area right in front of the chuck, the same gibb pressure/tension will result in the carriage binding up completely when it is moved to the almost virgin area of the lathe bed that has seldom seen friction or wear. The lathe bed/dovetails are simply several thousands of an inch thicker in the area where the carriage binds up.
All mills/lathes with slides will wear more in the area of the machine that is heavily used. If this is the case, the only way to use the slide over the full use of its range is to adjust the gibbs so that you have a good working tension on the virgin area of the bed and endure the loss af accuracy because the slides are corespondingly loose or sloppy in the machines sweet spot where it has been used the most.

Another common issue is that your lathe is not "level."
This doesnt mean level to the horizon. It means that the bed is straight with no bends dips hills or twists.
Even a relatively light weight lathe less than 2000 pounds needs to be leveled with a precision straight edge and .0001 machinists level to ensure proper carriage flow over the full length of the lathe bed. This is the purpose of the machinist level.

The AL bed on that Taig is a noodle. If it isn't "level" you may be binding up the carriage for that reason. If you can borrow a precision straight edge you will be able to troubleshoot this variable.

Good luck sir.
Eddie
 
I just saw tsp&b's reply after I posted. I think he may be right on the friction point. I think there are wear/rub marks there in the channel where he pointed out. If that's the case you might have an easy fix. That small gear might be hardened but it would be quite simple to shorten it with a common bench grinder and then (important) remove any burrs left on the gear teeth.

Eddie
 
Ya, the pinion definitely looks like it's in too far and rubbing from the swirl marks on the wall. You should be able to just adjust the depth with the bracket or back the tube out a little that holds the pinion. When I put mine on, I push it against the wall and just back it up just where I know it won't rub.
 
You need a stop collar on the pinion shaft to limit how far through the carriage bush can go.
 
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