Thicknessing Nylon

[Trigger]

Hi All,

I'm planning to make a cross cut sled for my Bosch GTS10 table saw. Like some other manufacturers Bosch don't use the standard 3/4'' mitre slot but some other curious T slot. Try as I might I've not been able to track down any mitre slot runners to fit so I want to make my own.

Wood doesn't seem a good idea as swelling will occur and they will wear quickly causing the sled to stick or slop about.

My question is this. Would something like nylon 66 square bar be suitable and could I carefully take it down to the desired size using my thicknesser without damaging the blades or is a table mounted router a better bet ?

Cheers
Trig

 

[tiler99]

I made a bar out of two pieces of steel bought from b&q. Fits nice but did have to use a belt sander to fine tune it.

 

[Woody Alan]

Hi

Have you thought of using a suitable size of ground flat stock from someone like www.cromwell.co.uk under the materials and mtce section then click materials and all should become clear, you may be lucky and find your exact size or one that requires a couple of careful passes with a draw file for a perfect fit. File a slot under the end and fit a washer to catch in the "T" of the slot and away you go.

Alan

 

[Bean]

Hi
Nylon or polyprop cuting board would make an excellent runner. But I would be caucious about thicknessing it. As this is usually done in a scaarfing machine, basically a horizontal bandsaw.

 

[Chris Knight]

Nylon turns well, I should think it would plane well too.

 

[OJ]

Hi,
What is the table itself made from?
If it's aluminium, then any steel is out really as it will always bind.
I think ground steel is OTT and possibly a bit hard for this application and will possibly wear the slot larger even on a steel bed over time. Well seasoned hardwood would be my preference, easy to work and likely to be from old stock so good reuse of materials.
Nylon isn't that dimensionally stable and is quite soft. Machining it is tricky, but it does cut well in the lathe. I'd guess that it will load your planer blades. The trouble is that with a router, planer etc, nylon will always try and weld the swarf back to the sheet. It is soft, so will tend to squash in the thicknesser rather than cut. That's why it's used in a nyloc nut. Tufnol of other man-made laminate would be suitable, but whatever you use, I would choose what I had around if possible to use resources sensibly. If your workshop is prone to damp, make sure that your chosen material isn't prone to changing shape with humidity otherwise it will stick in the winter and be loose in summer. A lot of plastics will do this.
Let us know how you get on. All the best, OJ

 

[ike]

I don't think you will harm your thicknesser. The worst that can happen is the shavings will stick to the blades.

Ike

 

[Trigger]

Thanks for the ideas everyone.

The bed is aluminium so I can understand the point about disimilar metals and wear.

The nylon option sound feasible to machine as some of you have commented but having done some research OJ's point about the material changing shape with moisture / temperature looks spot on.

I've got a piece of 1.2m x 50mm square teak thats been in my wood store for the last 8 years or so, so I think I'm going to try that for starters as there will be nil cost to me. If that proves problematic I think the Tufnol sugestion sounds good. I've successfully routed that in the past and I've got a 600mm x 600mm peice of 4mm left from another project I could maybe bond together with a good epoxy to my requred thickness and then router it to the correct width.

If none of the above work I'll sketch up the runner cross section and take it to a small engineering company and get aluminium bar milled up.

Thanks again for the advice and ideas

 

[woodbloke]

Trigger wrote:

1.2m x 50mm square teak

Unless you've got special blades in your P/T this is one timber I wouldn't plane as it will blunt blades HSS ordinaire in no time. When I was a college in the 70's and teak stuff was popular, this is the one timber that the machine shop refused to plane so as a consequence when you collected your bundle the next day there was a lot of hand planing to do - Rob

 

[Trigger]

Thanks Rob,

Looks like Tufnol or alternatively I've got some old american oak flooring that I could clean up and use.

Will it be okay to cut Tufnol on my bench saw or will that damage the blade ?

 

[Scrit]

As bean points out Nylon 66 is normally horizontally milled, as is UHMW-PE, but the difference is that UHMW-PE will machine through a planer thicknesser with considerably less risk of kickback than the Nylon 66. It has the same sort of friction characteristics as PTFE (Teflon) and from my experience is a heck of a lot safer/easier to saw to size than any of the nylons or Tufnol. If you want to know how tough PE is - I've machined the slides bearings (basically 900mm long L-sections, 50 x 60mm x 12mm thick) for dustbin compactor wagons out of 500 grade (softer than true UHMW-PE which is the 1000 grade); four of these slides will hold a 15 tonne compactor body and contents and go through about 3,000 to 4,000 compact and empty cycles before requiring replacement, normally because foreign matter (steel, etc) has gotten into the bearing bed and sheared away pieces of the plastic rather than wear failure or because the high tension steel bolts holding the L-sections have sheared. Not bad for 1/2in thick plastic......

If you are going for metal I'd have thought that brass or phosphor-bronze (both traditional bearing shell materials) would be more suitable than aluminium as well as having a lower coefficient of expansion. The best timber would have to be lignum vitae - traditionally used for shaft bearing blocks in steam ships

Scrit

 

[jasonB]

If you go the metal route then do not use aluminium in an alloy table as it will gaul and stick. You should always use different materials for bearing/sliding surfaces. The bearing bronzes will be hard to abtain in flat section but brass should bot be a problem. Bright mild steel will be OK on a table (thats what my kity has) ground gauge plate is OTT and you will have a job getting flat stock narrower than 2" and if you try to harden a long thin length it will nodoubt distort unless done by a pro.

You could try an off cut of corian which can be worked with a router. Or PTFE as scrit says

Jason

 

[Scrit]

You could try an off cut of corian which can be worked with a router.

Surely Corian is just an acrylic/polyurethane co-polymer? If that's the case then acrylic scrap from the local signwriter's skip might do as well, although it wouldn't be as hard wearing as the UHMW-PE and I suspect Corian wouldn't be, either

Scrit

 

[Trigger]

Thanks all I really appreciate the advice

Looks like I've got a couple of options here. I'm interested in the UHMW-PE after what you have said about it Scrit so I'll price this up and post my findings.

 

[ike]

Trig,

KISS. There is not much to worry about with mild steel sliding on ali. It'll be far stiffer and more precise than any plastic, and a general machine shop will skim a bit of cold-rolled bar to suit. To give you a similar lower friction to plastic material, just use a PTFE lube spray (less than 2 quid fron Screwfix). Job done.

cheers,

Ike