Just how bad sliders can be?

At a glance,ie holding the slider up to the light and looking down the bore, the slider pictured did not appear [to eye] not that bad.
My bore gauge suggested it was very worn ...in fact after boring and reaming it's now 39.2 mm and still as a slight hollow 3/4 down the bore.
Standard 1.1/2 ,38.1mm ..so this was worn a staggering 1mm plus =40 thou! .
This wear is normally "more" in one plain , As Ludwig as stated oil changes are important!

I have stated before about how the spring snakes and rubs its "belly and Back" on the stanchion inner wall when compressed, this rubbing produces shards of spring steel .
These shards mix with oil/water to produce a "lovely" grinding fluid !
A modern problem is the stanchion internal surface finish , with cheaper tubes.

I have compressed a spring onto a 12mm rod and then pushed the "snake" into a stanchion , placed onto a bath scale the spring required 1 kg to get it to move..this force is greatly increased with the rougher finished Ebay stanchions . Its surprising how worn some springs become.

So change that oil yearly or sooner, remember "that" grinding fluid is also grinding away damper internals ,bushs and seals ..as well that micro chrome plating! It's not only the external dust that wears the chrome..but the beast that is out of sight :!:


The reamer is a David Brown floating type , Not really suitable in a tail stock, i am making a special holder for mounting on the tool post and power feed , and a bespoke kerosene feed through the lathe spindle , to wash out the chippings and lube the cutters.

Hello Rob
Interesting set up on your lathe. A few questions if I may, it is easy to see how you have trued the top of the slider (using the three screws) How have you set up the bottom of the slider? have/are you using the screw hole at the very bottom centralised on a close fitting pin held in the lathe spindle nose? for the coolant feed this pin must be hollow? Do you load the slider onto this pin,then fit over it, the steel tube holding the three screws?
I have never used one of the floating type of reamers (used plenty of the usual hand and machine reamers) how do you set the diameter you want to cut? Do you have to grind up a new tool bit to suit each required diameter?.
Please excuse me if the next bit sounds like I,m trying to teach my granny to suck eggs!
You mentioned that you want to have the reamer fastened to the tool post (so you can use the power feed)
On some of the lathes I have used in my career some of them have a additional Morse taper tool post that mounts on the cross slide dovetails (it actually lives there permantly, just pushed to the back of the saddle) and when required it is slid into position (against fitted stops so you don't have to bother aligning it) and locked into place, Drilling a hole with a 3" drill is childs play if the lathe is big enough!
Dean, Smith & Grace and Colchester are two of the makers that offered these items
Regards
Peter

John - I will be interested to see your results. As you said, you will be making up a tool holder for the tool post, so perhaps we should wait to see how this goes?

How do you ensure the slider bore is parallel to the lathe bed and on centre?

What sort of finish can you achieve with the reamer? Maybe some more photos when you get the chance?

Edit: just posted this while Dobba was posting.

As no one making new Roadholder sliders no more and a JBW fan I've wondered if slider could have layer of JBW put in say with a paper tube to leave large hollow then remachine?

NORTON 850 - 1974

Item: FORK SLIDER (PINCH BOLT SIDE)
Part Number: 063318
Price: £148.00

OK are these sliders new production last decade or 40 yr old unsold unused left over items? If new production then best bargain going at price of fancy new tire so just wasting time to try to spiff up worn ones to somewhat better function. If one able to get satisfaction out of being a corrective machinist [as opposed to being a new custom part maker] then that's its own reward but not applicable to most of us non machinists. Am I mistaken that John's reboring this instant slider still leaves section too wallowed out so still not going to correct bush clearance along whole fork travel? If so what has been gained w/o JBW filling in? Did John leave out the part of making new bushes to fit the new bore ID?

Im sure John either makes new bushings or sleeves the old slider. If he can beat the retail price of a new one with a
margin worth it to him, then he is good to go.
Once he is set up to do this job he might be able to turn them out in short time so giving him a decent profit margin.

All new- we make a new batch or two of the variants every year. Also the featherbed ones (round section/Imperial threads). See http://www.andover-norton.co.uk/SI%20Forks.htm

Joe/Andover Norton

Alrighty ZDF that means someday we'll read of a completely all new parts Commando, cool. Just stem tagged frame remains to produce. I look up to the competent machinists just don't care to be one myself only a dumb pilot wearing out and breaking stuff they can fix so I can do it again. Oh yeah might consider having Bore Tech treat sliders bores.

Hi Peter,

Spot on with the bottom location/pin , the lathe as per most as a morse 3 in the spindle. a cut down drill is machined to 3/4 x 40 long ,tough material! , the slider is located onto this ensuring a central location .

The slider as to be clocked true at the seal end, then the bore is machined untill the wear is just left in . This needs to be done with a Long bar..the 25mmx300mm bar is not sturdy enough, so i am making a 35mm bar from hard steel, If the boring is not done the David Brown reamer will float into the wear zone. Nasty!!

The David Brown will adjust ,and follow a bore..excellent piece of kit.

dobba99 said:

Hello Rob
Interesting set up on your lathe. A few questions if I may, it is easy to see how you have trued the top of the slider (using the three screws) How have you set up the bottom of the slider? have/are you using the screw hole at the very bottom centralised on a close fitting pin held in the lathe spindle nose? for the coolant feed this pin must be hollow? Do you load the slider onto this pin,then fit over it, the steel tube holding the three screws?
I have never used one of the floating type of reamers (used plenty of the usual hand and machine reamers) how do you set the diameter you want to cut? Do you have to grind up a new tool bit to suit each required diameter?.
Please excuse me if the next bit sounds like I,m trying to teach my granny to suck eggs!
You mentioned that you want to have the reamer fastened to the tool post (so you can use the power feed)
On some of the lathes I have used in my career some of them have a additional Morse taper tool post that mounts on the cross slide dovetails (it actually lives there permantly, just pushed to the back of the saddle) and when required it is slid into position (against fitted stops so you don't have to bother aligning it) and locked into place, Drilling a hole with a 3" drill is childs play if the lathe is big enough!
Dean, Smith & Grace and Colchester are two of the makers that offered these items
Regards
Peter

Click to expand...

hi see above .
Finnish is not 100% yet! But there is bore burnishing rollers that will produce a chrome finish , or a honer with aluminum white stones.. The normal blue stones are iffy, But stand the slider up and 1/4 fill with kerosene will polish up the finish .

daveh said:

John - I will be interested to see your results. As you said, you will be making up a tool holder for the tool post, so perhaps we should wait to see how this goes?

How do you ensure the slider bore is parallel to the lathe bed and on centre?

What sort of finish can you achieve with the reamer? Maybe some more photos when you get the chance?

Edit: just posted this while Dobba was posting.

Click to expand...

New peek bush's and boring ,when tooled properly should be approx £160 a pair. But i need the stanchions or can provide British made for another £100,

Onder said:

Im sure John either makes new bushings or sleeves the old slider. If he can beat the retail price of a new one with a
margin worth it to him, then he is good to go.
Once he is set up to do this job he might be able to turn them out in short time so giving him a decent profit margin.

Click to expand...

So does it stand to reason then that external springs are heathier for our forks due to the absence of internal spring-shard grinding paste. External springs were recently being discussed in another post, and it seemed that the consensus was that external springs were not superior to internal springs, just owners' preference for appearances sake.

Well most manx or Tritons use external springs , but need good chrome stanchions,

L.E.N. said:

So does it stand to reason then that external springs are heathier for our forks due to the absence of internal spring-shard grinding paste. External springs were recently being discussed in another post, and it seemed that the consensus was that external springs were not superior to internal springs, just owners' preference for appearances sake.

Click to expand...

Hello John again
My first rule of boring deep holes in the lathe is to use the 'biggest boring bar you can get in the hole'
Regarding the 'spring against the stanchion' wear, will polishing the springs help at all? One of the 'tuning secrets' with air rifles is to install a low friction liner to stop the spring 'slowing down' too quickly. Has anyone tried a P.T.F.E. liner in the stanchion to combat the spring wear problem?
Regards
Peter

john robert bould said:

Hi Peter,

Spot on with the bottom location/pin , the lathe as per most as a morse 3 in the spindle. a cut down drill is machined to 3/4 x 40 long ,tough material! , the slider is located onto this ensuring a central location .

The slider as to be clocked true at the seal end, then the bore is machined untill the wear is just left in . This needs to be done with a Long bar..the 25mmx300mm bar is not sturdy enough, so i am making a 35mm bar from hard steel, If the boring is not done the David Brown reamer will float into the wear zone. Nasty!!

The David Brown will adjust ,and follow a bore..excellent piece of kit.

dobba99 said:

Hello Rob
Interesting set up on your lathe. A few questions if I may, it is easy to see how you have trued the top of the slider (using the three screws) How have you set up the bottom of the slider? have/are you using the screw hole at the very bottom centralised on a close fitting pin held in the lathe spindle nose? for the coolant feed this pin must be hollow? Do you load the slider onto this pin,then fit over it, the steel tube holding the three screws?
I have never used one of the floating type of reamers (used plenty of the usual hand and machine reamers) how do you set the diameter you want to cut? Do you have to grind up a new tool bit to suit each required diameter?.
Please excuse me if the next bit sounds like I,m trying to teach my granny to suck eggs!
You mentioned that you want to have the reamer fastened to the tool post (so you can use the power feed)
On some of the lathes I have used in my career some of them have a additional Morse taper tool post that mounts on the cross slide dovetails (it actually lives there permantly, just pushed to the back of the saddle) and when required it is slid into position (against fitted stops so you don't have to bother aligning it) and locked into place, Drilling a hole with a 3" drill is childs play if the lathe is big enough!
Dean, Smith & Grace and Colchester are two of the makers that offered these items
Regards
Peter

Click to expand...

Click to expand...

Have my forks apart (RE but they have a Norton front end) and there is obvious wear on the outside of the springs.
Your mention of a sleeve occurred to me. As the spring doesnt compress without "snaking" for want of a better word
would the sleeve also help with this?

I have worked on other things with springs (mostly aircraft stuff) And have found teflon sleeves on them. Never noticed any indication of spring wear, so might prove to be a good solution.

Rather than a sleeve why not coat the spring in teflon paint.

Teflon paint?
Please note the fork spring and application is harsh , when the spring can be ground away ..is paint really going to work?
I have the feeling this is a bit of Scottish humor :lol:

kommando said:

Rather than a sleeve why not coat the spring in teflon paint.

Click to expand...

I've thought of having the Titanium Oxide nano powder dry friction coat or nickle carbibe silica burnishing but realized as John says it'd be rubbed back to raw metal by time I got to end of drive way. I'd say a good part of the dampening action comes from spring friction in stancions. I learned the hard way brake fluid don't prevent rust so after months of Trixie set up for some serious let down her forks would compress some but stayed down till I sanded springs and stancions inside smooth again.