Myford Super 7 Apron removal

[Martin Standish 2Participant @martinstandish2]

I am trying to remove the Apron on my Super 7 which has a gearbox and powered crossfeed.

First question please – can the Apron be removed with the lead screw still in place?

If the lead screw needs to be removed I assume it moves away from the gearbox towards the right. Can anyone let me know how to remove the lead screw from the gearbox end? Do I need to remove the chain gear quadrant assembly and various gears to gain access to what I assume is the lead screw retaining nut?

Any advise will be much appreciated.

Thanks

Martin

[Martin Standish 2Participant @martinstandish2]

[LambtonParticipant @lambton]

Martin,

It would be a great help to you to lay your hands on a Genuine Myford handbook for the QC gearbox.. This details how to fit the gearbox to various typed of S7. The instructions are fully detailed and should be easy to reverse..

Best regards

Eric

[Brian OldfordParticipant @brianoldford70365]

I don't have the gearbox model but I can assure you the lead-screw needs to be removed to the tailstock end before the PXF apron can be removed.
I had to do that when one of the screws in the dog clutch mechanism decided to make a break for freedom. Fortunately it only damaged itself and nothing else.

[Martin Standish 2Participant @martinstandish2]

Posted by Lambton on 10/12/2019 17:04:01:

Martin,

It would be a great help to you to lay your hands on a Genuine Myford handbook for the QC gearbox.. This details how to fit the gearbox to various typed of S7. The instructions are fully detailed and should be easy to reverse..

Best regards

Eric

Thanks Eric. I have the S7 owners manual but I can't find anything specific on lead crew removal.

Regards

Martin

[Martin Standish 2Participant @martinstandish2]

Posted by Brian Oldford on 10/12/2019 17:30:47:

I don't have the gearbox model but I can assure you the lead-screw needs to be removed to the tailstock end before the PXF apron can be removed.
I had to do that when one of the screws in the dog clutch mechanism decided to make a break for freedom. Fortunately it only damaged itself and nothing else.

Ok Brian

I just need to fathom how to detach lead screw from othEr end.

Regards

Martin

[JohnFParticipant @johnf59703]

Martin, here is a link to the gearbox manual

Forgot to say how old is your machine ? you can check the age with the serial number on the Myford site, earlier machines may well have a different gearbox and the installation is different

Broadly for what you need to do there are two type of lead screw, the later one passes through the gearbox to the gear train, the earlier one is connected to the gearbox with a sleeve on the RHS of the box. There may well be variations to this as well. My S7 is c1977 with power cross feed and I did have occasion to remove the apron, from memory –  first remove the gears on the LHS inside the change wheel cover then the dowels and screws on the RH end of the machine to release the lead screw support bracket, make sure the half nuts are open then withdraw the L/screw.

John

**LINK**

 

Edited By JohnF on 10/12/2019 18:54:00

Edited By JohnF on 10/12/2019 19:02:30

[ZanParticipant @zan]

That’s the way John I did that recently. But in answering the main question, you have to withdraw the leadscrew to remove the apron. After removing the right bracket, which will be achieved by bending the screw outwards to get the bracket off the dowels. The problem is re assembly. Briefly it goes like this

Edit.  Dratt .   I should have looked at the link before  writing an essay on the difficulty of refitting……deleted!

Edited By Zan on 10/12/2019 23:22:22

[Martin Standish 2Participant @martinstandish2]

Thanks that is really useful.

i think it must be a later model as the leads crew appears to be attached to the LH gears.

regards

martin

[egaParticipant @ega]

Posted by Zan on 10/12/2019 23:19:25:

That’s the way John I did that recently. But in answering the main question, you have to withdraw the leadscrew to remove the apron. After removing the right bracket, which will be achieved by bending the screw outwards to get the bracket off the dowels. The problem is re assembly. Briefly it goes like this

Edit. Dratt . I should have looked at the link before writing an essay on the difficulty of refitting……deleted!

Edited By Zan on 10/12/2019 23:22:22

Aren't those dowels tapped to facilitate their removal?

[Raphael GolezParticipant @raphaelgolez]

Hi Martin,

Chipping in for you. I have a S7 PXF with gear box. The way I remove the apron is to fully take the lead screw out as it passes via the half nut and the lead screw drive gear with key to transfer power to the cross slide. You need to remove the gear from the lead screw attach to the gearbox. To do this you have to remove the gears assembly and gear train that provides input to the gear box. Once done you can slide the lead screw out towards the tail stock provided you remove the lead screw attachment assembly on this side. If you have the type where you only have to remove 2 socket screw then its easy and the whole assembly can come off. However if you have the type that have 2 additional peg/dowels to stabilised this part then its sometimes difficult to remove it without applying to much force that can potentially damage this area. In this case the lead screw has to be remove toward the headstock side provide you take off the lead screw hand dials, but this will require you the remove the whole gearbox assembly to facilitate lead screw withdrawal towards the head stock side.

Once done you can proceed to disassembling the PXF apron which is the easy part. It comes off after removing the 4 top allen bolts and will drop down – be careful here as its heavy.

 

Hope this helps.

 

Raphael

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:35:06

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:39:34

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:40:29

[JohnFParticipant @johnf59703]

Posted by Zan on 10/12/2019 23:19:25:

That’s the way John I did that recently. But in answering the main question, you have to withdraw the leadscrew to remove the apron. After removing the right bracket, which will be achieved by bending the screw outwards to get the bracket off the dowels. The problem is re assembly. Briefly it goes like this

Edit. Dratt . I should have looked at the link before writing an essay on the difficulty of refitting……deleted!

Edited By Zan on 10/12/2019 23:22:22

There should be 2 tapped holes in the dowels to facilitate removal with a small puller, they are ??BA have to check and you need a piece threaded bar & nut or an allen screw, a tube and a washer. I have heard some machines do not have the tapped hole ??? but never seen one.

John

[Raphael GolezParticipant @raphaelgolez]

Posted by JohnF on 11/12/2019 14:07:00:

Posted by Zan on 10/12/2019 23:19:25:

That’s the way John I did that recently. But in answering the main question, you have to withdraw the leadscrew to remove the apron. After removing the right bracket, which will be achieved by bending the screw outwards to get the bracket off the dowels. The problem is re assembly. Briefly it goes like this

Edit. Dratt . I should have looked at the link before writing an essay on the difficulty of refitting……deleted!

Edited By Zan on 10/12/2019 23:22:22

There should be 2 tapped holes in the dowels to facilitate removal with a small puller, they are ??BA have to check and you need a piece threaded bar & nut or an allen screw, a tube and a washer. I have heard some machines do not have the tapped hole ??? but never seen one.

John

Hi John you meant to facilitate jacking up the dowels via the thread? It wouldn't be a dowel if it had a thread, instead it would be a tapped hole in which case a bolt would be logical. Mine had a two bolt holding it down and a 2 dowels. To be honest I never attempted to apply force here after removing the 2 bolts. I could not see any thread in the dowels either. Like I said if this is threaded how would you pin the dowel without damaging the thread unless its a threaded bolt you using.

Raphael

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 14:20:45

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 14:21:22

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 14:21:55

[DMBParticipant @dmb]

Hi All,

I understand that some S7 rhs bearings have dowels which are tapped 2BA, for the insertion of a puller. HTH

John

[Martin Standish 2Participant @martinstandish2]

Posted by RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:34:28:

Hi Martin,

Chipping in for you. I have a S7 PXF with gear box. The way I remove the apron is to fully take the lead screw out as it passes via the half nut and the lead screw drive gear with key to transfer power to the cross slide. You need to remove the gear from the lead screw attach to the gearbox. To do this you have to remove the gears assembly and gear train that provides input to the gear box. Once done you can slide the lead screw out towards the tail stock provided you remove the lead screw attachment assembly on this side. If you have the type where you only have to remove 2 socket screw then its easy and the whole assembly can come off. However if you have the type that have 2 additional peg/dowels to stabilised this part then its sometimes difficult to remove it without applying to much force that can potentially damage this area. In this case the lead screw has to be remove toward the headstock side provide you take off the lead screw hand dials, but this will require you the remove the whole gearbox assembly to facilitate lead screw withdrawal towards the head stock side.

Once done you can proceed to disassembling the PXF apron which is the easy part. It comes off after removing the 4 top allen bolts and will drop down – be careful here as its heavy.

Hope this helps.

Raphael

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:35:06

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:39:34

Edited By RAPHAEL VAL GOLEZ 1 on 11/12/2019 13:40:29

Thank you.

I was able to remove the gear holding the lead screw and then remove the lead screw to the right. The apron then came off easily.

After looking at the apron I have decided to replace a couple of the gears and all 5 bushes to try to remove some of the play.

Regards

Martin

[Raphael GolezParticipant @raphaelgolez]

Great to know that your on the right track Martin.

JohnF and John. Apologies for the confusion. You are both correct. The dowels are tapped 2BA on the inside and I can confirm it. John you are correct that this served as a way to jack out the dowels via a 2BA screw/puller.

Raphael

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