Help with taper attachment. Weeeeee

I have gotten the nerve to finally use the taper attachment to turn a Jarno taper for the spindle. Sadly I do not have the lovely micrometer dial, but Ive made do (if you have one pweeeeeese sell me). I used two indicators, a 2" to watch the traverse and another to watch the cross feed.

While observing and adjusting over and over I noticed that while traversing there is not an immediate travel in the cross feed, almost a half inch before the cross feed would start moving. I tinkered and tinkered trying to solve it but could not determine how to reduce this lack of movement. The machine has been well cared for and the taper attachment will glide like silk back and forth. Am I missing an adjustment which I can take up the slack? I knocked out the taper since I was working from an end, but I would like a bit more confidence on the next go around.

Thanks Gang!

A TA is a very useful thing, but it requires common sense to use well. Backlash is and will always be an issue in any machine's use. First, the best way to set the taper in a TA is mount a known standard in the spindle and verify its concentricity. Then with a dial indicator mounted on the carriage, adjust the taper angle for "0" deviation during carriage and indicator travel across the rotating standard. To do this, always run the carriage well beyond the end of the standard before engaging the carriage feed. As the carriage starts its travel, apply pressure against this travel taking out all possible backlash. Once "0" deviation has been achieved with the DI, no more adjustment of the TA is required, but at the start of every cut, the procedure above must be performed to remove all backlash.

mike.thomas1 said:

I have gotten the nerve to finally use the taper attachment to turn a Jarno taper for the spindle. Sadly I do not have the lovely micrometer dial, but Ive made do (if you have one pweeeeeese sell me). I used two indicators, a 2" to watch the traverse and another to watch the cross feed.

While observing and adjusting over and over I noticed that while traversing there is not an immediate travel in the cross feed, almost a half inch before the cross feed would start moving. I tinkered and tinkered trying to solve it but could not determine how to reduce this lack of movement. The machine has been well cared for and the taper attachment will glide like silk back and forth. Am I missing an adjustment which I can take up the slack? I knocked out the taper since I was working from an end, but I would like a bit more confidence on the next go around.

Thanks Gang!

Click to expand...

Nerve???? WTF?? I use my taper all the time, no magic to it. I use my DRO to set the angle, move the carriage to take up the backlash, 0 the DRO. move the carriage the proper amount, read the cross slide and adjust accordingly. Dead easy. A half inch of carriage travel before cross slide movement is no big deal. Why do you need a micrometer to adjust the taper? I have 3 lathes with taper and no micrometer, how do I get by?

Hopefully you know to tighten up the cross slide clamp A for the slotted draw bar - takes the CS screw / nut out of the picture

steve-l said:

A TA is a very useful thing, but it requires common sense to use well. Backlash is and will always be an issue in any machine's use. First, the best way to set the taper in a TA is mount a known standard in the spindle and verify its concentricity. Then with a dial indicator mounted on the carriage, adjust the taper angle for "0" deviation during carriage and indicator travel across the rotating standard. To do this, always run the carriage well beyond the end of the standard before engaging the carriage feed. As the carriage starts its travel, apply pressure against this travel taking out all possible backlash. Once "0" deviation has been achieved with the DI, no more adjustment of the TA is required, but at the start of every cut, the procedure above must be performed to remove all backlash.

Click to expand...

Thanks, I probably should pushed or pulled slack out before observing. That would explain the lack of repeatability in my observations of the indicators... Sadly I do not have a standard to dial in so I was adjusting with the gauges to achieve the dimensions according to the machinery handbook.

Moonlight, you are very fortunate to have a DRO, that would be a slick solution.

Johnoder, thanks, yes I confirmed all of this before I started. I am a little concerned that I found A tightened prior to me adjusting things. Is there any detrimental affect this could have on things?

mike.thomas1 said:

Sadly I do not have the lovely micrometer dial, but Ive made do (if you have one pweeeeeese sell me).

Click to expand...

If I can manage to find some time to finish them up, we will have the TAFFEE** Kits available soon. Check our web store or the keep an eye on the Monarch sub forum for the announcement. Shop has just been way too busy for me to get them done lately. Soon, though.

( ** - Taper Attachment Fine Feed for EE lathes )

If both A and B are tight, you cannot move the cross slide

If A is tight and B is loose, the slotted draw bar moves with the cross slide

The thrust bearing is mounted on the slotted draw bar - meaning you HAVE NO FIXED DATUM for the cross slide - if B is loose

Then there is the possibility they WORE OUT the clamping action of A, making use of T/A erratic

mike.thomas1 said:

Johnoder, thanks, yes I confirmed all of this before I started. I am a little concerned that I found A tightened prior to me adjusting things. Is there any detrimental affect this could have on things?

Click to expand...

mike.thomas1 said:

Thanks, I probably should pushed or pulled slack out before observing. That would explain the lack of repeatability in my observations of the indicators... Sadly I do not have a standard to dial in so I was adjusting with the gauges to achieve the dimensions according to the machinery handbook.

Moonlight, you are very fortunate to have a DRO, that would be a slick solution.

Johnoder, thanks, yes I confirmed all of this before I started. I am a little concerned that I found A tightened prior to me adjusting things. Is there any detrimental affect this could have on things?

Click to expand...

I don't know that I am "fortunate" to have a DRO, I make my living with these machines, that DRO has paid for itself hundreds of times. Just buy one, They don't cost that much. Before I had money to buy one I clamped digital calipers to each axis, that was my DRO for a long time. I still have them on the tailstock of each lathe.

I looked through Cals photo documentation of his disassembly and can't determine what A engages. I think I should assess any damage that could have been cause by the potentially decades of use tightened down.

mike.thomas1 said:

I looked through Cals photo documentation of his disassembly and can't determine what A engages. I think I should assess any damage that could have been cause by the potentially decades of use tightened down.

Click to expand...

Sort of a flattish tee nut tapped for bolt A. Fits thru slot in draw bar

40 and 41 here

Pulled the set screw that was in A, apparently it was simply in place as a plug, peered into the hole and no sign of it , yay, time to disassemble cross slide?

A couple things to add to the T/A operation.
For best size and finish, always cut external tapers from Big end to Small end. Internal from small to big end.

The reason for this is the play in each moving end point needs to be loaded in the same manner. The Carriage moving left to right external taper, the cutter wants to push away from the work, so it puts the connecting bar in tension, and the same time the angle of the T/A slide pulls the connecting bar opposite direction, creating tension as well, so tension against tension takes out any backlash in the many points of backlash, clearance etc.
The boring of a taper small to big end, left to right carriage movement, Now the connecting bar is in compression, and the slide is in compression as well. Compression vs Compression takes out the backlash clearance again.


If you were to cut an external taper right to left, small to big. The cutter will put the connecting bar in Tension, and the slide will put the bar in compression, leaving all the points of clearance, backlash to go from loose to tight, tension to compression randomly. Finish and size suffer.

When I do tapers I turn the area to be tapered to the end diameter for its length, then lock in the T/A and cut the taper. You only need a few passes to finish the angle once major Diameter is cut.

While I don't think it's necessary with a properly adjusted taper attachment (everything's running on bearings including the shoe) you can always push the tool by running the spindle in reverse and cutting on the backside - assuming that I'm picturing your objection properly. But I've cut MT2 and MT3 inside tapers directly big end out (to enable testing with a master) with no issues. I am usually careful to leave the tool plenty of room before the cut starts to let the taper settle down before engagement with the work.

One way to eliminate taper attachment backlash can be seen at 9:35 min. mark here:
Turning a Taper using the Monarch Taper Attachment Part 2 - YouTube Repeat before every cutting run.