Member postings for Mike B 1

ok so i'm retreating form the al320 after looking carefully at the stepped compound slide and its lack of T slots. otherwise a nice machine for my purposes. I don't have space (or $) for a separate mill and a small mill/drill would not replace my drill adequately. So back to 26mm spindle bore machines with slotted slides. So maybe back to the tu2506 with (or not) and back standing milling attachment or maybe an older cq6128 (250x270x26) which is heavier and more solid than the tu2506 but with the same bed width tho the downside being belts to change the speed and still a minimum speed of 125.

i did have a long chat to a retired tool maker who spoke positively about doing lots of milling on a lathe with various attachments to the cross slide so that just makes it more confusing.

when someone said there was not the perfect lathe i didn't think it would be this tricky! the search continues...

i'll tell them its a wood lathe Chris, don't want to be like facebook

I'm in New Zealand Chris - Central Auckland... are you a kiwi?

tomorrow i'll go and measure the thickness of the lower cross slide section. obvioulsy thicker is better for tapping a thread into. any estimates of a minimum thickness that you would feel comfortable with?

thanks Jason - points noted. there is a vertical slide as an accessory for the al320 on the webpage **LINK** but I'll go and have a careful look at it in the morning.

Jason / Howard - re the cross slide lacking tee slots, there are a number of videos of people drilling/tapping holes into the cross slide to mount the vertical slide.... is this a bad idea? eg this: **LINK**

thaiguzzi - in an ideal wold, yes. I get the point that milling would be compromised. but i am constrained by space and money. so i'm looking for a viable start (lathe first) and maybe upgrade milling options later.

cheers

thanks for the very helpful comments. i think i'm getting a clearer picture. in a couple of days i've got some time to head back around the various shops and kick the tyres some more. currently i'm drifting towards the al320 option tho will check the cross slide and the back for a mounting area or other options. i am constrained on space and money so there are gong to be trade-offs. a Bridgeport is probably always going to be out of my range. But with so many forums posts where people talk about their first lathe being too small I'd rather not have that to look forward to.

when i finally put my money down i'll report back on what and why.

cheers

i'm going round and round trying to decide on a first lathe. the initial goal with be parts related to vintage motorcycles and then whatever else comes along. Initially i was looking at the optimum tu-2506v (25x500 x26mm spindle bore) with a bolt-on BV20AF mill combo. but the minimum speed is 150 for threads and the few reviews I've read suggest milling combo machines end up being quite limited. And i think the quality may be a bit variable on these lathes.

today's idea is an AL-320 (320x600 x 38mm spindle bore)- much sturdier machine and 60rpm minimum speed - and add a vertical milling attachment to it. that overall costs about the same as the option above, for a much better lathe (I think). but the milling capability will be more limited.

so the question - is a vertical milling attachment on a larger sturdier lathe going to be a lot worse than a smaller lathe with the combo attachment.? is this trade-off worth it? truth is I have no immediate plans or specifications for the mill but a month ago i did and had to get someone else to do it for me.

in case you were wondering, the budget has been increased significantly at least twice. it cant go much higher as i still need tooling etc.

thanks for any comments you can make.

Mike

thanks for that info -eek, not sounding good for the 2506v, tho better to know while the money is in my wallet

Edited By Mike B 1 on 09/12/2018 09:17:00

thanks Jason.

3D printing is an interesting idea

also for the 40T spindle driving 30T, that 30T driving 65T keyed to an 45T driving a 85T on the screw then I get 0.0005mm error per turn, or 0.046%.... yes?

so i conclude... it can be done!

so why don't they print these threads on the label?

Thanks John. The TU-2506 has a 40 tooth spindle gear and 3mm pitch leadscrew. I can calculate combos that produce 26tpi (+/- .05%) so am assuming it will work. just not sure if I'm right and I'm left wondering if it is just maths why don't the manufacturers specify more thread possibilities on the label. maybe there is more to it?

Hello

This is a very noob question…. I’m intending to buy a lathe which I will eventually want to cut 26tpi threads (for vintage british motorcycles) and I’d like to understand change gears and thread cutting a bit better before buying.

In my budget and location (New Zealand) there are limited choices and most have a metric leadscrews. I’m eyeballing the optimum Tu-2506v, but it doesn’t specify 26tpi. I’ve read that an imperial leadscrew will cut imperial threads more accurately than a metric leadscrew will. But many with metric leadscrews also specify combinations for imperial threads (like the tu-2506). I assume it’s about maths and what % error I’m happy to live with, and not so critical when the threaded item is not too long. So…

1. is it true that if I can calculate the tpi or pitch from the given change gears then the machine will cut it, whether metric or imperial leadscrew? (assuming the gears will physically fit on to the banjo)

2. if so, what is a ‘reasonable’ % error on the pitch that I would want to live with? I’ve calculated the error at up to 0.3% from the change wheel combinations shown on the lathe I’m looking at (metric leadscrew-->imperial thread).

3. Is it thereby true if I buy (eg off ebay) some other change gears of other teeth number then I’ll get even more options? Any ‘gotchas’ on this?

Thanks for any help and clarify you can offer

Mike