Bedway vee angle

This topic has 36 replies, 14 voices, and was last updated 30 March 2016 at 12:01 by Martin Connelly.

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13 February 2016 at 20:36 #225240
Danny M2Z
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@dannym2z
Posted by AlanW on 12/02/2016 17:34:06:

In my repeated attempts to get it to fit, the notch is now too big to salvage by files or scraping but that may be my route for the next attempt.

If you just require to use the carriage stop, how about covering the way with release paper (baking paper). Degrease the notch in the stop, fill it with JB Weld and clamp in place while it sets.

It should then fit your way and once the edges are tidied up only you will be the wiser.

Maybe not engineering perfection, but it should result in a functional item.

* Danny M *
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14 February 2016 at 17:08 #225369
AlanW
Participant
@alanw96569
Neil,

If that was Ally Pally, I somehow missed it unless I just couldn't see for @!&%£#g back-packs.

Danny,

I presume you mean the metal repair putty. That is a thought but it does seem a bit 'bodge it and scarper'.
14 February 2016 at 18:20 #225380
Neil Wyatt
Moderator
@neilwyatt
Posted by AlanW on 14/02/2016 17:08:13:

Neil,

If that was Ally Pally, I somehow missed it unless I just couldn't see for @!&%£#g back-packs.

It was MEX 2104 at Sandown.

Neil
14 February 2016 at 18:20 #225381
Neil Wyatt
Moderator
@neilwyatt
Posted by AlanW on 14/02/2016 17:08:13:

Neil,

If that was Ally Pally, I somehow missed it unless I just couldn't see for @!&%£#g back-packs.

It was MEX 2104 at Sandown.

Neil
14 February 2016 at 23:04 #225404
Danny M2Z
Participant
@dannym2z
Posted by AlanW on 14/02/2016 17:08:13:

Danny,

I presume you mean the metal repair putty. That is a thought but it does seem a bit 'bodge it and scarper'.

It's only a carriage stop that's being clamped to the ways. No real wearing surfaces except maybe the threaded holes.

I have used JB Weld (metal filled epoxy) to repair holes in crankcases and to bed actions in high powered target rifles. It works very well and is readily available.

It is a bit of a bodge, but it is quite functional and practical.

This should let you get on with using your lathe and as you gain practical skills you may wish to make a more perfectly engineered stop.

I made my minilathe stop from aluminium alloy, the stop screw is 2BA brass, the clamp screws are 3mm HTS. It was also used as a test piece for anodising experiments. That was 8 years ago and it still works well.

* Danny M *
15 February 2016 at 07:16 #225430
John McNamara
Participant
@johnmcnamara74883
Hi AlanW

Wayne R Moore's Foundations of mechanical accuracy analyses various Vway angles.
One of the great classics of machine design engineering.

Try this google search

foundations of mechanical accuracy pdf

Regards
John

Edited By John McNamara on 15/02/2016 07:17:26
15 February 2016 at 09:20 #225435
Neil Wyatt
Moderator
@neilwyatt
Before jumping in to remaking, hang on for the next MEW.

It has some very simple lever/cam operated saddle stops in it that look much faster to use than screw up ones. Very tempted to make a couple myself.

Neil
15 February 2016 at 15:30 #225489
AlanW
Participant
@alanw96569
Danny,

In view of Neil's last post, I may give your suggestion a go for the short term and see what the next issue of MEW brings.

Neil,

Never been to Sandown Park; I avoid the M25 unless heading for Gatwick.

John,

That book is only available (legally) at exorbitant price.

Regards,

Alan
30 March 2016 at 11:07 #232438
Journeyman
Participant
@journeyman
Sorry to revisit an old post but I had a bit of a think about the original saddle stop design and came up with a solution. Not necessarily the best solution but it seems to work quite well. Rather than try to match the peculiar bed geometry I added a couple of "Mickey Mouse Ears" to the stop body. Now only need to fit to a couple of point contacts. I made a second version to test the princple using 6mm brass for the dowels.

Despite the small contact area it clamps really firmly. Details of the mod on Journeymans Workshop.

Cheers

John

Edited By Journeyman on 30/03/2016 11:26:08
30 March 2016 at 11:21 #232439
John McNamara
Participant
@johnmcnamara74883
Great Idea!

There is a bit of a risk that it might leave a mark in the bed way over time? Maybe a solution would be to machine a flat on the round dowels to spread the load. They would self align. I would use epoxy or Loctite to make the aligned angle permanent.

Regards
John
30 March 2016 at 11:31 #232441
Journeyman
Participant
@journeyman
The dowels are Loctited in, I thought they would develop flats with use being a lot softer than the bed. I had to "adjust" the vertical face of the clamp body to get a good 3-point fit.

John
30 March 2016 at 12:01 #232447
Martin Connelly
Participant
@martinconnelly55370
I have been considering making a positionable home/limit switch for a lathe with CNC. It needs to move because the difference in the safe stop position between spindle collets and a 3 jaw chuck is significant. In my case the near edge of the bed is where the angle is, the top and far side of the way are horizontal and vertical. This sort of design will save the need to accurately measure the angle then reproduce it in the design. The clamping load for a switch positioning block should be much lower than that needed for a mechanical stop so al. alloy and brass are suitable materials and I will not worry about marking the ways.

Martin
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